gm 4.3 to 350 motor swap?

Question

i have a 1990 GMC sierra and i need to know if the motor mounts on the 4.3 v6 are the same as the 350 ones or will i have to move them any thing helps thanks

Answer 1

the motor mounts are the same, all Chevy V8 (except the 307)motor mounts are the same as the 4.3 v6.
the 4.3 v6 really is just a 350 minus the 2 front cylinders, it doesnt sit any farther forward or backward, its just not as long.
and everything except the injectors will work.

people also need to realize that he is talking about a Fullsize truck with a V6, not the s-series Sonoma.

Answer 2

first of all - 350 Pontiac heads will in good shape a 4 hundred and 455 Pontiac V8. All Pontiac V8s the comparable dimensions. A small block GM is a chevrolet. 2nd - much less cc's interior the top provide you an greater compression ratio (CR) - greater cc's provide you much less CR. Then 1974 8:one million heads provides you with 8.seventy two:one million on a 4 hundred. The 4Xs 8:one million, the 6x's between 8:one million to eight.37:one million. The 4x heads pass concerning the comparable as or greater desirable than the 6x - some 4X are the small combustion chamber heads from a 4 hundred - some are great from a 455. The combustion chamber sizes between a 6X and 4x -7H (the 4 hundred) are rather close. seem for a 7H stamping on the top - that provides you great valves and small combustion chamber. examine previous subject concerns of severe overall performance Pontiac (HPP) for added info on that. My 4x's got here from a 1974 grand am (4 hundred cu in). cc the heads to ascertain - in the event that they're over a hundred cc's you have the 455 heads. in case you have the sturdy 4X - save your money. the main suitable 6X heads have is a ninety one cc Combustion chamber - the 4X-7H had 98cc. word - maximum 6X's had ninety 8 too - the ninety one's are greater stable to discover. In the two case you may mill them to get what you prefer. The 4x and 6X are a warm low $ setup for a 455. the 2nd element to ascertain is how your 350 heads will pass vs. the 4X's - a 10th of a factor of compression ratio won't propose plenty if the pass is down. examine the valve sizes - The intake is each so often smaller on the 350 heads than 4 hundred - the exhaust may be the comparable. Your 350 heads could be the two a 4C or 40 six casting. 40 six had the small intake valves (one million.ninety six) and 4C had the two.11s. in keeping with the hyperlink below the small valves easily pass greater desirable than the greater desirable (and 4X/6xs) - pass determine. sturdy good fortune - If it replaced into me - freshen up the 350s, examine they pass greater desirable than the 4Xs, port tournament the intake and exhaust, multi-attitude the seats, bolt them on with a sturdy set of headers and function relaxing. The valvetrains would be ok - yet whilst the heads are off - open up the pushrod holes - that provides you an selection later to run one million.sixty 5 rockers for greater carry and effectual era with out swapping cams. i did not try this and am kicking myself now.

Answer 3

they are different and you can buy the kit from many places online, do a google, you will need special headers too, find them online too,

or you could use 80-up style 305 and 350 manifolds you may have to dent the firewall a little to make the studs clear, get them from any 80-up chevy gmc truck under 1 ton, or from any 80-up 305 or 350 car, caprice, monte, cutlass, 82-up firebirdor camaro and so forth, they are the above spark plugs style manifolds, long straight narrow ones, car ones have two stud outlets, truck ones have three stud outlets, otherwise identical, if you need a pic of what im talking about then IM or email me

good luck

Answer 4

You will have to buy new mounts for the motor and the truck, the ones from the V6 are futher back in the truck due to the engine being shorter.

Answer 5

try a search engine. the whole 350 in an s-10 has been done many times.

Answer 6

they will be the same the difference in the engines is in either the legth of stoke or the piston diameter but not in the mounts