motor swap ?'s

EMPIRE231 · July 27, 2004

I have a 90 chevy 1500 w/ 4.3V6 & auto trans. is it difficult/pricey is it to swap to a 350 w/ turbo 400 trans? what all would be needed. I'm guessing new engine/trans mounts...and most likely I'll want solid mounts. other than that...would my current AC/ power steering stuff work?

also...would the turbo 400 trans be the ideal transmision? It'll be for an offroad desert truck geared pretty high...probably 5.15's or so. and the motor would be built to around 375-450HP.

thanks in advance

OUMike · July 27, 2004

Empire,

This is an interesting topic. I think you'll find a lot of helpful information if you look in the archives. I maybe wrong about this but I would emagine that a 4L60-E (the tranny that should be in your truck now) is tougher than the Turbo 400 you mentioned. Good luck, and keep us posted..

99-2door · July 27, 2004

I maybe wrong about this but I would emagine that a 4L60-E (the tranny that should be in your truck now) is tougher than the Turbo 400 you mentioned.

Don't think so. The TH-400 was designed to sit behind big blocks and engines with high HP and torque numbers. The 4L60e is notorious for being a little weak, especially the extra crappy V6 version. Most people believe even the TH-350 is stronger than the 4L60e.

The 4L80e is the replacement for the TH-400, used in HD applications.

Besides, a 90 has a 700r4 not a 4L60e.

Chris97K1500 · July 27, 2004

Yeah, I'd agree with 99-2door. When you ever see a project vehicle using a GM big block, they always use a 400 turbo Automatic. Project Copperhead on TRUCKS! used a Turbo 400 with a 572 cubic inch Crate BB from GM, which makes over 600 rwhp and torque. My cousin did this exact upgrade from a 3.4 to a 5.7 a few years back, I'm not sure you have to get different motor mounts, you do if it's an S10, but you can find them at advanceadapters.com if needed. (probably not needed) Chris

OUMike · July 27, 2004

Ah...well I stand corrected. So say, one wanted to swap with a standard MPI V8 (5700 maybe) with an older tranny. Would their be any percaustions one would wanna take while doing this?

99-2door · July 27, 2004

The V-6 motor mounts are different. At least there is a plate they sit on that moves them forward. The plate bolts to the frame, just remove it and bolt on the v8 mounts.

EMPIRE231 · July 27, 2004

most likely I would need to fab up some solid engine mounts due to the abuse that it will be seeing. so would my AC/STEERING stuff still work w/ the 350? what year 350 should I be looking for, because I kinda want it to be smog friendly . should I step up to the turbo 400...becuase some people say that a decently built 700r4 should be able to handle that much power?

Thanks for all the help so far...and I will definantly keep you guys updated.

99-2door · July 27, 2004

most likely I would need to fab up some solid engine mounts due to the abuse that it will be seeing. so would my AC/STEERING stuff still work w/ the 350? what year 350 should I be looking for, because I kinda want it to be smog friendly . should I step up to the turbo 400...becuase some people say that a decently built 700r4 should be able to handle that much power?

Thanks for all the help so far...and I will definantly keep you guys updated.

so you are building a racing truck, but you want to leave the AC and smog legal?

EMPIRE231 · July 27, 2004

lol...yeah. well I did say "kinda smog friendly" and that's becuase the class Iwill most likely race is 1450/sportsman...which requires you to have a valid registration. soo...I know one legality is that the motor should be of the same year model or newer...we dont need to worry about the other stuff . oh and about the AC....wouldn't it be nice to be doing 80mph + through the desert without breaking a sweat? the truck will be a race truck...but also a play truck during regular desert trips...so it would add to the pimp/bling factor

99-2door · July 27, 2004

lol...yeah. well I did say "kinda smog friendly" and that's becuase the class Iwill most likely race is 1450/sportsman...which requires you to have a valid registration. soo...I know one legality is that the motor should be of the same year model or newer...we dont need to worry about the other stuff . oh and about the AC....wouldn't it be nice to be doing 80mph + through the desert without breaking a sweat? the truck will be a race truck...but also a play truck during regular desert trips...so it would add to the pimp/bling factor

Might be cool, probably be a little taxing on the cooling system during a race, not to mention the added weight. I would think to have the truck competitive you would need to strip everything not necessary for the race or registration.

I was just wondering what kind of end goal you had in mind. Are you planning on driving this truck on the street?

EMPIRE231 · July 27, 2004

the truck would rarely be drivin on the street...but sometimes it will be...just for fun or sometimes in the desert you could take the highway back to camp. most likely during a race I would remove the belt for the AC (depending on how bad of an effect it'll have on the truck). but while I'm just playing around I would want the AC, just in case, also for prerunning the course. but the truck will be a trailer queen on the way to the desert/race. the truck will be completly caged (engine/cab/bed), all sheet metal from the firewall forward will be removed and a tubular core support will be built into the engine cage. most likely the frame from the cab-back will be hacked off, due to the 4 link suspension and the bed cage will incorperate the fuel cell, spares, shock towers, etc., all carpet/headliner/interior will be removed...race seats and 5 point harnesses will be built into the cab cage...and I'm debating between a full custom aluminum dash...or just running the stock one w/ some modifications done to it w/ all the guages built into it....

sorry for the long post, but that's kinda a rough breakdown....I'm just trying to figure out the drivetrain