Tired Straight-6, upgrade to V8?
 

This 292 struggles on grades, and I don’t mean steep grades, just rolling hills. And it gets a bit warm when cruising on the freeway. It just seems like it’s had it’s day. Not sure if I should look for a GMC V6 305 or something like a 283 or 350.

It’s a 63 C20, 292, 1bbl; T5 5-speed.

Re: Tired Straight-6, upgrade to V8?
 

There will be a lot of cats that will say to keep the inline... but, you'll never have as much fun with an inline as you will with a V8. Can an inline make power like a 350 V8... sure... but you'll spend a lot of cash doing it. A 350 is easy to work on, and super easy to build power with. No brainer to me.

I'd ditch that T-5 as well...

Gary

Re: Tired Straight-6, upgrade to V8?
 

If it struggles on grades are you in o/d 5th gear.
If so shift down.
Get the motor back into it’s designed most efficient power rpm.
Swapping to a 350 likely won’t be the wonder cure you’re looking for.

Re: Tired Straight-6, upgrade to V8?
 

What trans would you go with?

Re: Tired Straight-6, upgrade to V8?
 

The rear is geared at 4:10 right now, however, I am planning on converting it to 3:42. It tops out at 65mph, @2300 rpm. Even if I shift down to 4th it still lags and slows down.
The motor just doesn’t have any power.

Re: Tired Straight-6, upgrade to V8?
 

If you need it to work like a truck, an SM465.

If you wanna play in it like a muscle car, an M-20/21 or a Super T-10

If you want OD, a T-56 or a TKO

Gary

Re: Tired Straight-6, upgrade to V8?
 

It's amazing what a rebuild and another camshaft will do along with an HEI. I would also look into a carburetor change to a 2bbl. Either the dual jet rochester or a motocraft 2100 2bl.

Another edit: Since you're running the T5 already I would not waste the money on a gear change. The 4.10s in 5th gear equate to a 3.23 ratio.

Re: Tired Straight-6, upgrade to V8?
 

I have a lot more fun with my L6 292 than I do with the 350, but the former is built and the latter is a stock crate motor.
My 292 is the original engine, rebuilt with .030-over Badger pistons, Crane 260H cam, Rhoads lifters, oversize intake valves [1.84''], GM HEI, Offy intake, Edlebrock 1404 [500 CFM] 4 Barrel carb, Clifford headers. SM465 4-Speed, N-type crossover exhaust, 12-Bolt 3.73 rear, 235/85/16 tires on 6x16 whitespoke wheels.

GMC V6s were audacious engines, but parts are scarce, and there was never a HI-Perf aftermarket.
Everybody and their cousin has a V8.
Your truck, your choice.

Re: Tired Straight-6, upgrade to V8?
 

If you're going to swap, swap in a v8, not the GMC v6. It's heavy and doesn't rev high at all. Makes a ton of torque though.

I enjoy my little 283, but I have no clue what, if anything, has been done to it internally.
I have dreams to build a 292 powered truck one day though.

If you do choose to go v8, you'll need to swap out the passenger side frame stand from the 292 specific to the v8/230/250 inline 6 frame stand. I've got a set for the v8 that I'll trade you for the 292 set if that's the direction you choose.

Re: Tired Straight-6, upgrade to V8?
 

I have the side motor mount/frame stands for the V8, it came with my fron crossmember when I installed disc brakes.

Re: Tired Straight-6, upgrade to V8?
 

I’m going to stick with my T5 for now; not looking to do burnouts or drive it hard. It’s just a cruiser. Besides, my Ranchero transmission is getting rebuilt, so no dinero.

Re: Tired Straight-6, upgrade to V8?
 

I can't remember, did you do a compression test on the 292?

Re: Tired Straight-6, upgrade to V8?
 

Yes, long time ago - everything checked out ok.

I’m wondering if I should try and advance the timing a bit. Maybe that would help with keeping the temp down.

Re: Tired Straight-6, upgrade to V8?
 

A V8 can get 20mp and have over 350hp with an overdrive transmission. The modern internal combustion engine has matured a long way since the L6's. I'm in favor of junking the old reliable and going modern. But that's just me.
Do what you enjoy and can afford.
Cheers

Re: Tired Straight-6, upgrade to V8?
 

I would, it does help with overheating and also helps with performance. I dont know how much advance a 6 will tolerate but after a lot of reading about small block timing, (initial, mechanical, vacuum etc) I nailed it on my 283 and wow it really helped.

Re: Tired Straight-6, upgrade to V8?
 

My old 67 and 65 both had hei’ s and I had them at 14 initial. I live at sea level.
If you live at higher elevation then your motor might tolerate a bit more than that.

Re: Tired Straight-6, upgrade to V8?
 

T5 is fine unless you put something with torque in there. 350 or above will shorten its life considerably. Perfect trans for the 292, or a 283 v8 though.

Personally, I'd put a V8 in it just for the exhaust noise. Anything can make decent "around town, not hod rod" amount of power.

Re: Tired Straight-6, upgrade to V8?
 

I have a lot of love for 283's but if your not happy with a 292, a 283 won't be the ticket either. 283's can be spirited and fun in a half-ton shorty, but when saddled with the extra mass of a 3/4 ton long bed it won't be the same. Sometimes, when I have a heavy passenger, my stock truck's 283 can feel it.

An HEI is a great distributor and I put them in every Chevy I've ever had. The aftermarket supports them well with different counter weights and springs, adjustable vacuum advances, coils etc.
Getting mine dialed in right required a degreed balancer tape, (a dial back timing light works too) which let me know my total advance, my tach and a helper to let me know at what rpm it was "all in". My total advance was low so I changed my initial timing from 12 to 16 (a huge increase from the factory spec of 4 degrees) which still kept my total advance at a tolerable level. In my case I knew I had taken it too far when the motor pinged upon lugging it a bit off idle with the clutch. (Other engines have pinged upon short shifting under heavier throttle)

Geezer has previously posted an excellent article on the subject and it was very helpful along with the advice he and other "distributor doctor's" gave me right here on this site. The expression "timing is everything" holds true in life and engines. I wouldn't give up on that motor without really trying to optimize an HEI for it.

Re: Tired Straight-6, upgrade to V8?
 

I have a new stock distributor with Pertronix conversion installed right now. Would I need something like this?
https://www.summitracing.com/parts/sum-850043

Guess I could try advancing the timing first, then maybe a 2bbl carb.

Re: Tired Straight-6, upgrade to V8?
 

http://www.crankshaftcoalition.com/w...nition_advance the article that Geezer posted.

https://www.crankshaftcoalition.com/..._a_timing_tape make a balancer tape.

https://www.crankshaftcoalition.com/...g_for_movement check the hub on your balancer for slippage.

Re: Tired Straight-6, upgrade to V8?
 

That's a nice one but Ive had good luck with buying more economical HEI's from my local parts store. As for advancing your existing distributor, where is your timing now? It would be nice to know the "all in" amount and at what RPM so as to have a base to start from.

Re: Tired Straight-6, upgrade to V8?
 

I'll have to check; if I remember correctly I am at about 10 degrees BTDC.

Re: Tired Straight-6, upgrade to V8?
 

As you can see the original set up on my V8 was a bit vague. It didnt even have any real numbers on it.. The timing tape was way cheaper than a dial back light, it's got all the info I needed, and it looks cool too 😎.

Re: Tired Straight-6, upgrade to V8?
 

Ultimately, that motor likes 16 degrees on the crank, the mechanical advance adds another 14 all in by 2000rpm. That puts my total at 30 which is still a couple degrees lower than other folks run, but like I said adding more to the crank made it ping off idle. The only way to get more up top was to modify my distributor which wasn't important enough for me to do it.. As a side note...my vacuum advance pulls another 22 degrees when I'm at even throttle.

Re: Tired Straight-6, upgrade to V8?
 

Summit has balancer tapes for a variety of different diameter balancers. https://www.summitracing.com/parts/m...hoCY4YQAvD_BwE