4.3L to LS1 swap.....help/advice needed

firestorm91tt · March 6, 2005

Hello,

Newbie here looking for some senior insight in regards to doing a engine/tranny swap (4.3L stock set up to LS1).

I have a 1994 GMC Sierra SL with 225,XXX miles. The stock 4.3L engine and automatic tranny are beat. Needless to say she is tired and a new engine/tranny install would be nice. I have access to getting several stock LS1 engine and tranny combos to include all accessories, ECM, harness etc.

My question is how much of a PITA is it to swap out the stock engine/tranny for a LS1 set up. Is there any difficulties in dropping in a new set up. What is all involved as far as possibly modding brackets, wiring etc. I really dont have a clue as to what what all would be neccessary for the swap. I do know that a bigger radiator and electric fans will need to be added if I go the LS1 route. Will new motor mounts be needed....and are header clearence an issue.

Is there any links that show a LS1 swap with pics and dialogue that may help me along the way during my install. I would like to research this project as much as I can before I actually purchase an engine/tranny.

firestorm91tt · March 10, 2005

TTT

Cool Zr2 · March 10, 2005

A 94 truck..... well, it won't be hard at all if your handy, but........ I personally don't think it will be worth the investment. But there is an exception, if the truck was a show truck or was in better than mint shape.

If I were you, I would just put in a 350 tbi, and a new trans, very cheap and, to me, a better idea.

But that JMO

scooter70 · March 17, 2005

LS1 swaps are cool. Check out the Hybrids & Conversions section at LS1Tech.com. You might consider a 5.3 or 6.0 as they're cheaper and more plentiful. The swap is exactly the same, regardless of which motor you get.

-Matt

My LS1 Powered 1970 Corvette

99Silver6.0 · March 17, 2005

You need to get in touch with Allen Nelson. He runs Nelson Performance. Hes got an OBS Silverado with an LS1 in it. Its been done but im not sure how much fun teh process is. I think Allens actually in the process of putting a 6.0 with an STS in his truck now. Look for him on his board, his name on there is farmtruc

LS1Truck.com