What GM create engine to buy for 3/4 ton 72 C20

[Chilly178]

Hello, a few months ago the 350 in my C20 started knocking. Instead of rebuilding it I am looking at the small block create engines by GM. http://www.chevrolet.com/performance/crate-engines Specifically the SP350/357 looks pretty good with the Vortec heads and hydraulic roller cam,
little expensive though.http://www.gmperformancemotor.com/parts/19367082.html anyone have any experience with these and know if it works with mechanical fuel pumps? And what parts do I need when buying a deluxe engine, also would this engine work with my current "thin belt" setup and pulleys? Or do I need a whole different serpentine system. I plan on keeping the same SM465 and Eaton no slip rear end. What crate engines are you guys using? Or am I better off rebuilding mine? Thanks.

[52napco]

Rebuild yours with a mild rv cam... I bought a 350 crate back in the summer and it's a bit disappointing...wish I would have built mine instead.

[JMC1965]

Mine went kaboom and I just installed ATK HP32-C with the FITech EFI. Truck is a 67 C20.

Pretty happy so far (only 1 month in though so I’m still taking it easy)

http://www.high-performance-engines....ors-s/2195.htm

[truckster]

If you want a crate 350, the L31 Vortec is an excellent choice. You'll need an intake manifold and electric fuel pump, but you'll get a one-piece rear main seal, a roller cam, and the best-flowing heads GM ever produced for the SBC. It should be good for around 300 HP, but the usable torque curve is much broader than that 290 HP engine you're looking at.

[garyd1961]

Originally Posted by truckster

If you want a crate 350, the L31 Vortec is an excellent choice. You'll need an intake manifold and electric fuel pump, but you'll get a one-piece rear main seal, a roller cam, and the best-flowing heads GM ever produced for the SBC. It should be good for around 300 HP, but the usable torque curve is much broader than that 290 HP engine you're looking at.

This^. I have had mine for about a year now and couldn't be happier with it. Mine is in a 1970 c10 long bed and it will get down the road. I have a Summit Stage 1 intake, Holley 4 barrel and headers with 2 1/2 inch exhaust.
ETA- The center bolt valve covers like the one piece rear main seal don't leak like the old style does. I didn't like the center bolt valve covers at first but now I prefer them over the old valve covers. No need to tell me yours don't leak because everyone knows they leak sooner or later, usually sooner.

[mike16]

look carefully at where the usefull HP begins max's out and where torque begins and peaks.

wow those 290 hp crate motors are outreageous in price.

[Chilly178]

Yeah that's retail I think here is a different website.
http://www.gmperformancemotor.com/parts/19355659.html

[kwmech]

You could build from your 350 a 383 and still have money left over from that crate price

[6T7 C10]

I am about a month away from firing up my L31-R GM long block crate engine. It has been fun doing it and I would do it again. You will need an electric fuel pump as it is not drilled for a mechanical pump. I went this route for its simplicity, historical reference and bolt in ability versus a LS swap (nothing against LS swaps as that is on my bucket list). I gathered a HEI ignition, low profile dual plane manifold, small four barrel carb, serpentine belt system and ram's horn exhaust manifolds. Just for fun I put in .015" Fel-Pro head gaskets, 1.52:1 full roller rockers and painted the entire engine Chevy orange.

I think it would be a good choice for your C20 as that is what was in C20's in the 90's and the best GM had to offer in mass for the small block. Any mods and torque converter stall should be done with low end torque in mind.

[FirstOwner69]

In 2010 or 2011, I bought a 350HO Deluxe for my '69 C20. At that time, it was rated at 330HP with a Holley 670CFM carb. It is a Vortec head engine with a flat tappet cam. The Deluxe engines do not include a belt drive setup, serpentine or V-belt. When I bought mine, it included everything else except a fuel pump. I believe the current version does not include a fuel pump or water pump (mine had a long water pump). The flexplate on mine was a 153 tooth. I needed a 168 tooth. I'm using a short water pump. I'm also running ram horn manifolds which require different plug wires than those supplied with the engine.

To answer your questions...
- This engine uses a mechanical fuel pump like your original engine.
- The original alternator and power steering and brackets bolted right on. However, the front and rear top A/C brackets that attach to the heads did not due to the different style intake manifold used with Vortec heads. I fabricated brackets based on some brackets used in earlier/different SBC applications.
- If your current engine still has a points distributer, you'll need to set up the truck for HEI.

I am very satisfied with this engine and would buy it again. It performs well and runs great. A lot peppier than the original engine which is in storage. There is a hesitation when the engine is cold. I'm pretty sure all I need to do to fix that is do some tweaking to the Holley.

I did not buy mine at Summit Racing, but here's a link to it on their website.
https://www.summitracing.com/parts/n...SABEgLVZfD_BwE

[jocko]

I have a personal "thing" about center-bolt valve cover hold downs, I have no idea why... While there are a few dual-valve cover hold down bolt and "old" intake manifold dual drilled heads out there, most of those vortec heads are for big inch small blocks (and pricey). As for aluminum options, I would rather have cast iron than aluminum on a daily driver personally.

While I'd like a 1 piece rear main seal because the 2-piece tend to eventually dribble on the floor, I've noticed they also require a neutral balancer, but externally balanced flexplate. Which I find a bit odd, but they do according to most of the info I've read on these.

Since what I REALLY want to do is just replace my stock (1x replaced) 350 with a stock GM 350 - and since I kind of prefer the GM new engines that haven't been over-bored, i.e. stock with the above criteria of perimeter bolt valve cover cyl heads and 2-piece rear main seals (all internally balanced), that leaves the 195, 260, and 290 hp GM crates.

Weird little nuances to these engines... I've yet to figure out the difference between the 195 and 260 hp engines... Both have the anemic cams (.383/.401 int/exh) but have 8.5:1 compression, whereas the 290 hp engine has a better cam (.450/.460) but 8.0:1 compression. One step forward and one step back.

While I really hate to crack open a brand new crate to upgrade the cam, that seems like the best option - the 195 or 260 hp crate with a subsequent buyer-installed cam upgrade. Nothing wild, but nothing dead like what it comes with either. That would yield a bit more potential in at least an 8.5:1 engine over the 290 hp's 8.0:1 I'd think. Anyway, speaking of thinking, I think perhaps I'll just continue my search for a stock 72 engine and rebuild it. Maybe make it a 383. Don't mind building them, I do enjoy that part of a resto. And even though I've rebuilt several, I probably still can't match the reliability and somewhat less mistake prone build of a good ol GM mfgr'ed engine. That's why I've been leaning toward a crate. My truck isn't numbers matching and it's not that important to me (although I WISH it was ). I do prefer them to at least look stock, thus my aversion to center hold down bolts on the valve covers I guess I don't see the 260 hp engine at GM or Summit anymore, only Jegs.

I DO wish they (GM perf parts) made a crate GEN 1 sbc with about 9-9.2:1 compression and a decent cam. To get that, ya gotta go with vortec these days it seems.

Perhaps a 383 vortec with the perimeter bolt adapters for the valve covers... Hmmm. Those are quite a bit more pricey than the Gen 1s, but great little stump pullers.

Anyway - does anyone know the difference in the details of the 195 and 260 hp GM Gen 1 crate engines? Thanks!

[davischevy]

Originally Posted by jocko

I have a personal "thing" about center-bolt valve cover hold downs, I have no idea why... While there are a few dual-valve cover hold down bolt and "old" intake manifold dual drilled heads out there, most of those vortec heads are for big inch small blocks (and pricey). As for aluminum options, I would rather have cast iron than aluminum on a daily driver personally.

While I'd like a 1 piece rear main seal because the 2-piece tend to eventually dribble on the floor, I've noticed they also require a neutral balancer, but externally balanced flexplate. Which I find a bit odd, but they do according to most of the info I've read on these.

Since what I REALLY want to do is just replace my stock (1x replaced) 350 with a stock GM 350 - and since I kind of prefer the GM new engines that haven't been over-bored, i.e. stock with the above criteria of perimeter bolt valve cover cyl heads and 2-piece rear main seals (all internally balanced), that leaves the 195, 260, and 290 hp GM crates.

Weird little nuances to these engines... I've yet to figure out the difference between the 195 and 260 hp engines... Both have the anemic cams (.383/.401 int/exh) but have 8.5:1 compression, whereas the 290 hp engine has a better cam (.450/.460) but 8.0:1 compression. One step forward and one step back.

While I really hate to crack open a brand new crate to upgrade the cam, that seems like the best option - the 195 or 260 hp crate with a subsequent buyer-installed cam upgrade. Nothing wild, but nothing dead like what it comes with either. That would yield a bit more potential in at least an 8.5:1 engine over the 290 hp's 8.0:1 I'd think. Anyway, speaking of thinking, I think perhaps I'll just continue my search for a stock 72 engine and rebuild it. Maybe make it a 383. Don't mind building them, I do enjoy that part of a resto. And even though I've rebuilt several, I probably still can't match the reliability and somewhat less mistake prone build of a good ol GM mfgr'ed engine. That's why I've been leaning toward a crate. My truck isn't numbers matching and it's not that important to me (although I WISH it was ). I do prefer them to at least look stock, thus my aversion to center hold down bolts on the valve covers I guess I don't see the 260 hp engine at GM or Summit anymore, only Jegs.

I DO wish they (GM perf parts) made a crate GEN 1 sbc with about 9-9.2:1 compression and a decent cam. To get that, ya gotta go with vortec these days it seems.

Perhaps a 383 vortec with the perimeter bolt adapters for the valve covers... Hmmm. Those are quite a bit more pricey than the Gen 1s, but great little stump pullers.

Anyway - does anyone know the difference in the details of the 195 and 260 hp GM Gen 1 crate engines? Thanks!

I have no idea about the differences in the 195 and 260 crate engines.

I too have a negative vibe about center valve cover hold downs. The after market vortec heads we used on the Blazer were dual bolt pattern, so we used original valve covers. We had to redo the exhaust and oil filler tube because of the angle of the heads. The rear AC compressor brace wouldn't work either.

The 290 crate motor we used on the K10 worked great as an install. I had all the same emotions about the engines you mentioned. It has a nice lumpy idle and works well. It's not the torq monster we would like but is fine for pulling the boat and atv's.

[geezer#99]

THe only difference Jocko is the 260 hp one is because of a 4bbl (holley or eddy) and headers and likely intake.. THey assume you'll outfit the 195 hp one with a stock intake, carb (quadrajet or 2gc) and single exhaust.
http://www.jegs.com/p/Chevrolet-Perf...67244/10002/-1
At least that crate has a cam that's matched closer to it's compression ratio.
The 290 hp engine has a mismatched cam with it's low compression. Look at this chart to see a relationship between cams and compression ratios.
http://www.crankshaftcoalition.com/w..._compatibility

[jocko]

Originally Posted by geezer#99

THe only difference Jocko is the 260 hp one is because of a 4bbl (holley or eddy) and headers and likely intake.. THey assume you'll outfit the 195 hp one with a stock intake, carb (quadrajet or 2gc) and single exhaust.
http://www.jegs.com/p/Chevrolet-Perf...67244/10002/-1
At least that crate has a cam that's matched closer to it's compression ratio.
The 290 hp engine has a mismatched cam with it's low compression. Look at this chart to see a relationship between cams and compression ratios.
http://www.crankshaftcoalition.com/w..._compatibility

Thx Geezer, so the engines being sold are identical, just advertised differently based on what the buyer adds on - thanks, appreciate the info. Yeah, the compression ratio/cam combo on the 290 horse motor baffles me. I think the 195/260 with a cam improvement may be the way to go (for me) I’d rather change the cam than pistons, ha.

Anyone have any additional info on the internal/external balanced 1 piece rear seal approach? There are a lot of 383 crates floating around ought there so it can’t be that big of an issue - I just haven’t looked into it much yet. I guess I’m only used to internally balanced engines, even though GM has had fully external balanced engines around for decades. I’m guessing it’s just not really a big deal. And if that’s the case then maybe a 383 in sheep’s clothing (stock valve covers with perimeter hold down adapters) is what I am really seeking. If I didn’t care about the bone stock look, I wouldn’t care about the vortec valve cover look.

[67ChevyRedneck]

Originally Posted by geezer#99

THe only difference Jocko is the 260 hp one is because of a 4bbl (holley or eddy) and headers and likely intake.. THey assume you'll outfit the 195 hp one with a stock intake, carb (quadrajet or 2gc) and single exhaust.
http://www.jegs.com/p/Chevrolet-Perf...67244/10002/-1
At least that crate has a cam that's matched closer to it's compression ratio.
The 290 hp engine has a mismatched cam with it's low compression. Look at this chart to see a relationship between cams and compression ratios.
http://www.crankshaftcoalition.com/w..._compatibility

I've read a lot of these threads before and a lot of people have been happier with the lower HP version because it appears the "performance version" wasn't optimized for performance at all and has most of it's usable HP in high rpm range. I want my power down low. It's a 4K lb brick.

[jocko]

Originally Posted by 67ChevyRedneck

I've read a lot of these threads before and a lot of people have been happier with the lower HP version because it appears the "performance version" wasn't optimized for performance at all and has most of it's usable HP in high rpm range. I want my power down low. It's a 4K lb brick.

Thanks Jesse - I recall reading the same on here and that's why I dug into some of the details on my own. Great info on this forum - and some of the sites, Jegs, Summit, GM, etc all have helpful info if you piece it together by looked at them all. If I go with a pre-vortec, I will likely go with the 195/260 block.

[68Stepbed]

For a 3/4 ton, I'd get this hoss!!
http://www.jegs.com/p/Chevrolet-Perf...69813/10002/-1

[truckster]

A 1-piece rear main seal requires a different flywheel or flexplate (different center diameter) and that will be balanced for the 1-piece seal crankshaft - it has a weight on it and it's indexed with a pin so you can't put it on wrong. It's really no big deal.

I can't imagine why you'd want to go with a flat tappet cam when you can get the L31 Vortec with a roller cam and better heads for less money - by the time you add the intake manifold and fuel pump you'll still be money ahead. Read through the forums and you'll find a lot of people who complain about wiped cams, but not a single one with a roller cam. Plus the roller generally has a better profile because it opens and closes quicker.

You can get adapters for perimeter bolt valve covers for Vortec heads, but I like having valve covers that don't leak.

[jocko]

Originally Posted by truckster

A 1-piece rear main seal requires a different flywheel or flexplate (different center diameter) and that will be balanced for the 1-piece seal crankshaft - it has a weight on it and it's indexed with a pin so you can't put it on wrong. It's really no big deal.

I can't imagine why you'd want to go with a flat tappet cam when you can get the L31 Vortec with a roller cam and better heads for less money - by the time you add the intake manifold and fuel pump you'll still be money ahead. Read through the forums and you'll find a lot of people who complain about wiped cams, but not a single one with a roller cam. Plus the roller generally has a better profile because it opens and closes quicker.

You can get adapters for perimeter bolt valve covers for Vortec heads, but I like having valve covers that don't leak.

Copy on the flexplate, didn't realize they came with an index, so that solves that, thank you. But I don't think you can put a pre-Vortec intake manifold on the L31 can you?

[truckster]

Originally Posted by jocko

Copy on the flexplate, didn't realize they came with an index, so that solves that, thank you. But I don't think you can put a pre-Vortec intake manifold on the L31 can you?

Nope, that's why I said he'd need a new intake. The Vortec heads use an intake with 8 bolts, and the bolts are vertical rather than angled into the head.

[jocko]

Thanks Truckster, yes, familiar with the vortec manifold vertical bolts - that's part of my dilemma, wanting to use an original manifold. Missed where you said he'd need a manifold, sorry about that. All on the same sheet of music.

350/357 aside - if I go away from a Gen 1 head config, I'd either go with the L31 or a 383, your point is a good one. In that case it comes down to money, and if tight, L31 a great option.

[Chilly178]

Thank you everyone for the feedback! I think I have made up my mind and will go with the L31-R. Some questions I have is what parts I need to make this engine work in the 72. My engine mounts currently in the truck look nasty any suggestions on mounts? Will this bolt up to the SM465 with no issues with the correct(?) flywheel? Another question I have is how the serpentine system would work. My truck doen't have power steering or AC and I intend to keep it that way. It uses a old school simple thin belt setup that only goes to the alternator. Can I keep this simple setup and same alternator or I need to buy a serpentine kit for the L31-R? If I do have to buy a kit do they all come with power steering and AC provisions? What do I do with it? Also I would need a water pump, intake manifold for carb, new carb, exhaust manifold/headers?, HEI distributor, electronic fuel pump, air cleaner, and plugs and wires. Any suggestions or anything I'm missing for this. Also will the starter thats in the 350 in the truck now work with L31-R? Will the radiator be the same? Any additional wiring needed? I also saw somewhere you have to plug a hole in the block for a sensor? Any mods I should make to the L31-R before it goes on for more hp/ torque? Thanks

[truckster]

Originally Posted by Chilly178

Thank you everyone for the feedback! I think I have made up my mind and will go with the L31-R. Some questions I have is what parts I need to make this engine work in the 72. My engine mounts currently in the truck look nasty any suggestions on mounts? Will this bolt up to the SM465 with no issues with the correct(?) flywheel? Another question I have is how the serpentine system would work. My truck doen't have power steering or AC and I intend to keep it that way. It uses a old school simple thin belt setup that only goes to the alternator. Can I keep this simple setup and same alternator or I need to buy a serpentine kit for the L31-R? If I do have to buy a kit do they all come with power steering and AC provisions? What do I do with it? Also I would need a water pump, intake manifold for carb, new carb, exhaust manifold/headers?, HEI distributor, electronic fuel pump, air cleaner, and plugs and wires. Any suggestions or anything I'm missing for this. Also will the starter thats in the 350 in the truck now work with L31-R? Will the radiator be the same? Any additional wiring needed? I also saw somewhere you have to plug a hole in the block for a sensor? Any mods I should make to the L31-R before it goes on for more hp/ torque? Thanks

My block came out of a 4 speed truck. You're welcome to the flywheel, clutch disc, and pressure plate if you want them for the cost of shipping (PM me if you want pics). Stock engine mounts work fine - you can still get a set through most auto parts stores. The bolt pattern on the Vortec heads is slightly different, but you should have no problem making your alternator bracket work. You will need a new manifold - the Edelbrock 2116 if you're running the Quadrajet carb. The same water pump your stock engine has will work with the L31 (but get a new one). If you don't already have an HEI distributor, I would definitely make that upgrade (whatever engine you get). I'm using rams horns manifolds - you should have no problem with your stock manifolds as long as they're in good shape. Your starter and radiator should be fine (as long as they're in good shape). Your temperature sending unit will not fit in the head, but user A1971Blazer does a really nice job of turning them down on a CNC lathe to the correct thread size. You'll need to install an electric fuel pump, and I would recommend you put it on a relay tied into an oil pressure switch so it cuts off if there's an accident. I bumped up my cam just a bit to the Ramjet 350/HT 383 cam, primarily because my block was drilled for a mechanical fuel pump and the stock cam didn't have a fuel pump lobe, but the HT 383 cam should give me a nice boost in torque and a little more HP.

[jocko]

A little more info on the GM crates. Note that the L31 we've been talking about that lists for just a hair over $2000 is the base L31 - but it also has a slightly more expensive brother (I assume this is the L31R some have referenced - it's specified for 3/4 ton and up, whereas the base L31 is considered a 1/2 ton replacement). Anyway, L31R = L31 HD (same engine, just different terminology depending on where you're looking). From what I can see it has the exact same specs, but you get 4 bolt mains for your extra $200. If I were to go the GM crate with vortec heads budget route - either of the L31s is hard to beat bang-for-the-buck-wise. The HT383 has some impressive numbers (but an equally impressive price - more than double an L31).

Here they are:
L31 https://sdparts.com/i-19928727-gm-en...te-engine.html

L31 HD https://sdparts.com/i-19928425-gm-en...te-engine.html

HT 383 https://sdparts.com/i-19928346-chevr...SABEgKvj_D_BwE

Some interesting notes:
- The L31s have a hyd roller cam/383 has a hyd flat tappet
- 383 has a forged crank/L31s are cast
- L31s require electric fuel pump (as mentioned above)
- 383 includes manifold and ext balanced flexplate (not sure if L31s include a flexplate)
- 383 and L31 HD are 4 bolt mains, L31 is not.
- L31 CR=9.3:1 / 383 CR=9.1:1 (MUCH better than the 195/290 hp crates' 8.5/8.0:1 CRs)
- Both have decent lift cams, 383 is more aggressive, thus the hp delta..

Bottom line, I'm not building a race truck - but the extra 100 ft-lbs of torque of the 383 sure would be nice. However, very best bang for the buck imho is the L31 HD.
I think a set of center-to-perimeter bolt valve cover adapters may be in order... Anyway, just wanted to share. Hadn't heard of the L31 HD before - and I'd spring for the extra $200 to get 4-bolt mains personally, whether I needed them or not. I believe that $200 also gets you some upgraded exh valves and cyl head improvements (although I'm not sure what those improvements are). If, when the time rolls around and I happen to have won a small lottery, I might spring for the 383, but if it were gonna happen tomorrow, I'd go with the L31 HD. Significant improvement over the original 350 and for about the price of the Gen 1 195 or 290 hp GM crates. I guess maybe I can live with a vortec manifold bolt pattern and externally balanced flexplate after all!

EDIT: Note in the table below for the HT383 cam - it is a mis-print. HT 383 has a hyd roller, not a hyd flat tappet cam.

[davischevy]

I have the L31 in my 55 Chevy 210 2 dr. It is a very capable, smooth running little engine, but is a little anemic. It does fine, but the response to the go pedal is a little light to suit me.

The roller cam was the biggest factor in the purchase of the L31, but if I were to do it again, I would gladly pay for more torque and HP.

You can build a 383 cheaper than that HT383 and have a roller cam. I love the 383 we have in the Blazer.