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-   -   Keep my old SBC 350 or ditch it and get a Vortec? (http://67-72chevytrucks.com/vboard/showthread.php?t=797540)

WyattTX 12-02-2019 11:32 PM

Keep my old SBC 350 or ditch it and get a Vortec?
 
I'm thinking of rebuilding my 350 SBC, but I'm told a Vortec is a better engine.

If I bought a Vortec long block, how many of the old SBC parts can be carried over? I'd also like to use a Q jet on either one. Will the Vortec with a Q jet perform that much better, or should I just rebuild the engine already have? Thanks.

truckster 12-03-2019 12:44 AM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
There will be a night and day difference with the Vortec. In addition to about 100 HP, you'll have the advantage of an engine that will easily go over 250,000 miles, no break-in worries with a roller cam, and a one-piece rear main seal that will keep you leak-free for many miles. The Quadrajet is an excellent choice if you're going to remain carbed.

Some new parts you'll need:

Intake manifold
Flex plate or flywheel
Electric fuel pump
Melonized distributor gear

You'll also need to either change the front cover or get a plug for the sensor hole.

On my build I also change the cam to the GM 14097395 HT383/Ramjet 350 cam. With that combination it should easily put out 330 HP and around 400 ft-lbs of torque.

WyattTX 12-03-2019 01:30 AM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Thanks, what kind of Electric fuel pump would you recommend? Is the Bosch 044 a good choice?

truckster 12-03-2019 11:28 AM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Quote:

Originally Posted by WyattTX (Post 8636590)
Thanks, what kind of Electric fuel pump would you recommend? Is the Bosch 044 a good choice?

Bosch makes great products, but you could get a good pump for a lot less. I've used Carter pumps that lasted a long time, and I've read good reviews about the Airtex pump that's available on Amazon for around $32 right now:

https://www.amazon.com/Airtex-E8016S...=fsclp_pl_dp_8

Ziegelsteinfaust 12-03-2019 12:12 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
If your rebuilding the Vortec you can have the push rod hole drilled out, and install a new cam with the pump lobe.

The Vortec with the roller cam will not be susceptible to low or no zinc oils of today like a flat tappet engine would be. Although you can change that in a gen 1 too.

Any engine rebuilt today from about the 50's on. Has a good chance if driven alot as in a daily driver. To make it well past 200,000 miles. Old engines were not the issue, but the oil offering very little protection to today's oils was. Earlier babbet bearings I have very little knowledge on. A friend I knew daily drove a flat head V8 1955 F1 for 12 years, and roughly 175,000 miles. Using the best oil he could get 10-20 years ago. Yes it needed alot of maintenance, but it didn't burn much oil. He took it everywhere mind you quite slowly, but he did do it. Even with the 5 speed OD he said 65-70mph was its comfort zone with the gears he had in the back. Which still allowed the truck to be a easy driver, and haul stuff.

truckster 12-03-2019 01:49 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Quote:

Originally Posted by Ziegelsteinfaust (Post 8636782)
If your rebuilding the Vortec you can have the push rod hole drilled out, and install a new cam with the pump lobe.

That's actually one of the reasons I went with the HT383 cam - it has a pump lobe, and my Vortec is a rebuild of a block that had a mechanical fuel pump provision.

If you're looking for a crate motor, the push rod hole won't be drilled, but if you're looking to rebuild one you might find one with a block-off plate - if you do, it's been drilled. You'll need a bronze-tipped pushrod for a mechanical fuel pump - brass tip goes to the cam lobe.

For what it's worth, if I were starting over I would probably go with a crate engine.

Tom 12-03-2019 06:44 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Quote:

Originally Posted by truckster (Post 8636570)
In addition to about 100 HP,

Ummm no. Maybe 50hp extra. Heads = about 40 and the roller cam maybe 10. Otherwise its a standard small block 350 like all the old ones.

Dead Parrot 12-03-2019 08:16 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
If your existing block is in good shape, you can add vortec heads + cam + new lifters + new intake. Let's you keep your existing mechanical fuel pump with no extra machining required since you said you wanted to keep the Qjet.

GASoline71 12-03-2019 08:34 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Vortec 350's were available from 1996 to 1999. Unless you're talking about drinking LS Kool-aid.

Gary

WyattTX 12-04-2019 12:31 AM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Quote:

Originally Posted by Dead Parrot (Post 8636996)
If your existing block is in good shape, you can add vortec heads + cam + new lifters + new intake. Let's you keep your existing mechanical fuel pump with no extra machining required since you said you wanted to keep the Qjet.

This seems like the best approach, since I wouldn't be utilizing fuel injection. I'll keep it in mind. Thanks for the suggestions, everyone.

biketopia 12-04-2019 08:50 AM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
I'd use the vortec block, like stated before you get the one piece rear main, unless you have an 86 up block now. You can also use your current timing cover. Go with the factory roller block either have it machined for the push rod or just go with an electric pump. A vortec headed SBC and a LT1/4 hot cam is a pretty potent little combo 400ish HP. I had a set up like that in my Camaro, changed out the springs and used a different retainer but it worked great until I over heated it from my own neglect and roasted the engine.

Tom 12-04-2019 07:18 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Adding a roller cam to an a old block is WAY more expensive then using a new block and an electric fuel pump.

sweetk30 12-04-2019 09:36 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
plowed snow for years in my last k30 with tbi 350 and was happy .

new k30 with new gm long block L31 vortec 350 and edelbrock pro flo 4 efi = :metal::metal::metal:

burn less fuel / more power / super happy .

same axles and driveline under new k30 over old k30 .

bolted up my tbi era full serp belt drive no problems .

Rick Bollinger 12-04-2019 11:45 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
I am freshening up my 350 4 bolt with the elderbrock top end kit with aluminum heads. Kit number https://www.summitracing.com/parts/edl-2038 . I caught it on sale for 1400 and change with a free carb. Selling the carb takes the price down to around $1000.00. Machine shop is going to rebuild my lower end assemble the engine and break in run and dyno for around $1500.00 So for around $2500.00 a new street able 350 with around 350 hp. I could have gotten a rebuilt vortec for that but I knew what I had to rebuild. No knocks or hot runs since I have owned it so there's that piece of mind. Adding a Fi Tech efi should be ready to see the country when done.

b454rat 12-05-2019 11:31 AM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Vortecs went to 02 in vans. I thought roller cam was good for like 50 horse? Didn't think it was only 10. Either way Vortecs make more power than a traditional 350. But like mentioned it's cheaper to go with electric fuel pump than to go retro roller kit. Last time I looked into it (20 years ago) was a grand....

vince1 12-05-2019 01:20 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
After all the disassembly and cleaning, I put rings bearings, seals, timing and cam set in a 350. Later I phoned a Chev dealer up here for a price on a 350 long block. They quoted me $5700 plus taxes for their cheapest one and then I thought I had made the right decision in repairing the old one. On further reflection though I sure would have saved a lot of time by buying new. On the upside overhauling a SBC is no longer on my bucket list.

garyd1961 12-05-2019 06:15 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
I gave around $2100 for my brand new block and all GM crate Vortec about 3 years ago.
I thought I saw the same motor online for $2700 (HD version) a couple days ago and the 2 bolt version for a little over 2 grand. Of course that doesn't Include the extra stuff like intake and flexplate or installation.

Tom 12-05-2019 07:58 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Quote:

Originally Posted by b454rat (Post 8637888)
I thought roller cam was good for like 50 horse? Didn't think it was only 10.

The factory vortec cam is only 191/196@050", its puny.
Flat vs roller doesn't mean anything unless you compare specs. Sure, an aftermarket big ass roller cam could get you 50hp. But not a stock truck cam. Not a stock cam from anything actually.

WyattTX 12-06-2019 12:49 AM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
These are all solid ideas. Once I decide something I'll post. Thanks for the input, gentlemen.

rpmerf 12-06-2019 08:55 AM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Some thoughts, not sure how much of it matters.

Power rating for the 1970 350 LS9 found in C/K 10-30 trucks
Compression Ratio: 9.0:1
Gross Horsepower: 255@4600 RPM
Gross Torque: 355@3000 RPM

Now I'm pretty sure I've seen that the net horsepower was 195. This would be the number they went with after 1971.

Specs on the L31 5.7L Vortec 96-02:
Compression Ratio: 9.4:1
255 hp @ 4600 rpm
330 ft-lbs. @ 2800 rpm

The Vortec heads have 64cc combustion chambers. The 1970 heads have 76cc heads. This should change the compression ratio to about 10.2:1. That alone should give you some HP.

The Vortec heads have a relatively low limit on lift. I forget what it is, something like .450 before you hit spring bind. Stock cam has about .428 lift on the exhaust, so there isn't much room without modifying the heads.

biketopia 12-06-2019 09:53 AM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
You can toss on a set of LS1/LS6 factory behive springs and a retainer from crane with no modifications to the head and be good to go. The hot cam has lift of 525/525 with a 1.6 rocker. It's a fun little combo and very very streetable. I picked up a set of used take of springs when I did my swap, but I think you can get a set new for like 70 bucks. Here's a good thread I found when I was doing my vortec motor, https://www.thirdgen.org/forums/tech...ortec-lt4.html

Tom 12-06-2019 06:42 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Quote:

Originally Posted by rpmerf (Post 8638354)
The Vortec heads have a relatively low limit on lift. I forget what it is, something like .450 before you hit spring bind. Stock cam has about .428 lift on the exhaust, so there isn't much room without modifying the heads.

Spring bind isen't the issue, the factory springs will go .480" without issue. Its the retainer to casting boss clearance that is an issue. GM sells these heads stock with cams that go to .480" but tons of people claim issues with as little as .450" lift.

garyd1961 12-06-2019 08:30 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Forget hp, torque is what you want and at 375 ft-lbs at around 3000 rpm on the vortec delivers. The roller cam will open and close the valve a lot quicker than a flat tappet cam. It has a steeper incline and this makes more power than a flat tappet with the same lift.
The old 195 hp motor had something like 396/401 lift. The L31 has 414/428 lift. With the valves opening faster this adds quite a bit more power.
The Vortec heads are GM's cast iron version of their Corvette Fast Burn heads. They burn the fuel faster and more efficiently than the old type heads. That's why you don't need as much total timing with the vortecs. The heads also out flow any factory sbc heads ever produced.
One thing most people don't mention is the L31 uses low tension piston rings which put much less wear on the cylinder walls.
Personally I wouldn't waste my time on the old flat tappet motors. Chevy went to a roller cam for a reason.

68c10owner 12-07-2019 02:20 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
Stock Vortec 350 was 255hp. TBI was 210hp, think carbed 250 was about 170hp.

You could add vortec heads to your shortblock and even add a roller cam but I agree that the retro fit roller cams are expensive. Its the lifters actually that are expensive.

Personally I would rather use a late 80s-early 90s block over the vortec block. Some are actually drilled for the fuel pump but as mentioned can easily be fixed by the machine shop. Using a oem roller block allows the use of oem roller lifters. They do have limitations but for a street performance engine they will be fine. If you decided to use a mechanical fuel pump with a roller cam you will need a special fuel pump pushrod.

6T7 C10 12-07-2019 08:55 PM

Re: Keep my old SBC 350 or ditch it and get a Vortec?
 
1 Attachment(s)
I agree with the previous posters on the L31 benefits. I went the Vortec crate route to keep it classic with a touch of modern when I ditched the 250-6. Your carburetor would work fine on a Vortec specific intake manifold. I am using a spectra fuel pump SP1130 along the frame rail. Timing chain cover w/o the hole and yes to the mellonized distributor gear on the HEI distributor. Your accessory brackets will bolt up to the block and heads just like before. The only go fast goodies I have in it are the FelPro 1094 .015 head gaskets and 1.52:1 full roller rockers and it runs fine. Any questions please ask.


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