In reply to yupididit :
Good point, the newest L31 from a junkyard is (edit) 24 years old now. A iron block SBC is certainly a robust engine, but i doubt there's a 24+ year old example that i'd pull out of a junkyard and slap in a truck without a thorough rebuild. You can still get L31 longblocks, but they ain't exactly cheap... https://www.gmperformancemotor.com/parts/19432780.html So, the cost differential between an L30 to L31 swap and a L30 - LS 5.3 swap is probably minimal, possibly in favor of the LS swap if you can find the mythical $500 5.3 in a junkyard..
Jegs makes the bite a bit easier but still..ATK Crate L31 from JEGS
I get the allure of the 350. It's a true bolt-in. I can find running 350s for $250 and add $150 worth of gaskets and it drops in. The LS might be $500, but until you add flexplate adapters, motor mounts, radiator hoses, electric fans or a belt fan kit, and exhaust, it adds up fast. It's not so much of the cost of the motor, it's the conversion.
In reply to Curtis73 (Forum Supporter) :
Certainly there can be a little more cost, but if he was asking about a supercharger surely he can budget for an additional $200 for some motor mounts and hoses (you can leave the stock clutch fan).
And i am a firm believer that the 5.3 will be better in every metric than a re-gasketed SBC of minimum 24 years old.
In reply to Curtis73 (Forum Supporter) :
You'd get nickle and dimed with either option. But what end result do you think would bring the best driving experience?
yupididit said:
In reply to Curtis73 (Forum Supporter) :
You'd get nickle and dimed with either option. But what end result do you think would bring the best driving experience?
Honestly, I think that's up to the individual. I can tune a Qjet to be darn near EFI-like, and the satisfaction that I would get of knowing I don't have 3 miles of wire and 30 sensors to rely on can be a real nice way to sleep at night.
Having said that, I'm dropping an LS in my 67 LeMans instead of a hotted-up 455 because the LS A) has more potential, and B) weighs 250 lbs less.
My daily drivers for about 10 years were malaise-era cars that I did cheap head swaps and I had zero regrets that it had a Qjet and 1970s tech. I never felt the need to LS swap, or even EFI swap any of them.
Just personal taste.
NOHOME
MegaDork
8/15/24 11:15 p.m.
My only caveat when it comes to engine swaps is that "your first engine swap will teach you how to do it properly the next time."
For clarity, what are the requirements leading to this engine modification? Is he wanting to replace a "tired" engine because it's losing power, and therefore would be satisfied with a stock-level rebuild restoring original power? Or is he trying to hot-rod it, and make a 30 y/o full size truck drive like a sports car?
In reply to budget_bandit :
From reading the first post, a bit of both!
If one were to freshen up the stock engine, and change the gear ratio, (and not tell him what was done ) the guy would probably be happy enough.
But, that's just my take, based on what the op wrote.
No Time said:
If it's not burning oil or giving others signs it's on its last legs, I'd do the following to improve seat of the pants performance on a budget:
- Acceleration: swap the rear for one with lower gears. It's amazing what making a jump from 2.73:1 to something in the 3.40- 3.73 range will do for seat of the pants performance and burnouts.
- Sound: install a dual outlet chambered or flow through muffler and dual tailpipes. You could also go retro with a glass pack and Y to split to dual outlet. Leave the intermediate pipe factory sized to maintain velocity and not lose low end torque.
- Feel: install a Transgo shift improver kit. Follow steps to produce firm shifts and maintain lockup. The lack of slip when in 3rd or 4th will give the feeling of more performance because of the direct relationship between pressing the gas pedal, engine sound, and acceleration when done in conjunction with the gears and exhaust.
If he's set on swapping the engine, finding a 350 vortex will be the most straightforward and least frustrating option.
Having read through again, this makes an awful lot of sense. It might be enough to give him the driving experience he is looking for without getting into the engine at all. If he wants more power later on, he'd need it all anyway, so neither the effort nor money would be wasted. And they are not really contingent on which direction he went with the engine.
In reply to DarkMonohue :
One benefit of that approach is not need to pull the engine or trans, so each part could be done separately in a weekend or less.
Even the Transgo kit can be done without pulling the trans. You can just drop the pan and valve body to install the parts (Vaseline will keep the check balls in place during reassembly).
