4.3 to 5.7

[thrasher88]

ive been thinkin of swapin in vortec 350(l31) in to 05 silverado anyone done this swap? i heard it was pretty straight forward and didnt require a different wiring harness. i know the 6.0 would be alot better but i could pick up l31 for alot less and put a few goodies on it for less than the 6.0

[thrasher88]

?? ive heard that it is the easiest swap for the nbs. i know that gm still uses the l31 in mexico. not worried bout steppin back in time the 4.3 has been the same for a long time.

[thrasher88]

i would love to use 6.0 but they are way over priced where i live and hard to find. two grand for a motor with no wiring harness or accesories.

[DBYRD]

where do u live? i paid $1700 for mine with wiring harness and all accessories with 60k miles on it... the only 5.7's id consider are the ls1 and ls6. ur not even talking about a lt1 here, the 4.3 would be just as powerful with a lil effort if u just want a small upgrade cam the 4.3 or turbo it...

[thrasher88]

i already have a custom tune and open exhaust and no cats. i dont think the 4.3 can ever give me the power i want for a resonable price.

[ff_jeff]

Here is my 2 cents... instead of swapping in the old L31, save up money and wait until you have enough to buy a newer motor... Not to mention it will never pass emissions. Law says you cant have a Motor that is older than the vehicle installed in place of its existing Motor unless it came from the factory like that. Then it would need to pass the smog sniffer. wich it never will if its modded. The only way I would ever put a LT1 or older L31 in a newer vehicle is if it was specifically a race vehicle and never saw the street. And the motor I would put in would be completley race prepped for lots of spray or lots of boost.

[ChevyLee]

i just did a 4.3 to 6.0 swap.

i have seen some nasty 4.3's
they are strong motors stock. i would go with a lsx motor, they are about the same price as a vortec 5.7

keep looking you can get them anywhere from 500-2k depends on the mileage and who is selling it.

[thrasher88]

the reason i was thinkin the l31 is because i can pick one up for 350-500 and could do a 383 and cam for about the the same or less than a 6.0. im gonna keep lookin for a 6.0 for now may even consider a 5.3 since they are probally more of them available.

[ff_jeff]

good idea, But better to save the Duckets for a better idea...

[thrasher88]

yea im gonna call the local junk yards tommorow and see what they want for a 5.3. and on another note i tore the rear end out of my truck yesterday i think its the ring and pinion what would be a good ratio for 33-35's i have a 5spd and 33's and 5spd now. but will prolly do a v8 swap in a couple weeks. im thinkin 4.56 or 4.88