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91 grand prix 3.1 to 3.8 swap

91gpse

91gpse

New member
ok heres the deal... im putting a buick 231 series 1 3.8 into my 91 grand prix se. for those that dont know thats the carbbed version of the gtp motor.... i have the 4t60 trans and just was wondering how i should go about the swap? i mean im going backwards with the technology lol. from fuel injected to carbbed. like will it even fit? i know im gonna need to get a new oil pan or modify the one i have. but like the bell housing bolt pattern, will it line up? and will i need to reinforce it? i mean the 3.8 i have has a cast iron block and the stock 3.1 has an aluminum block. were talking around 150lbs heavier lol. also would i need to change my fuel pump to a lower pressure one? i think that just about covers everything. oh and i know it wont fit under the hood.... i got that planned out already.... can you say cut off wheel and welder? lol

also... the reason i decided to do a carbbed 3.8 is cuz everyone wants a gtp motor nowadays i wanted to do something that was different.... plus i had the motor already.... and it only has 64k miles on it and its from 1980 lol i planned on building a buick t type with it but never found one in a decent shape and bought the grand prix instead.... i know its quite the undertaking but im up for the task... besides how many people on here have a grand national motor in their grand prix? lol
 


I think the bell housing are different from that 1980 model 3800 verses the later 3800. I bet that 4T60 won't bolt up to it without some sort of adapter.
 
ive been thinking about that... the 3.8 i have is made for a rwd so there is a good possibility it wont fit... but i wont know till i get it out of the car and measure.
 
me and a few friends of mine came up with an idea and i wanted to get an opinion of it.... ok i got a full rwd drivetrain for the 3.8 so..... we came up with the crazy idea of putting it in the grand prix and make it a rwd... i know itll be a alot... and i mean alot... of work but i have the means and the time so why not since i got everything already......

plus... itll alow me to drop the engine down and not have to do major surgury to the hood and have the valve covers sticking out of the hood....
 
ok something came up.... i may have to sell the car in the next month.... if youd be interested theres pics of it on my profile it needs a new motor thats it.... well cam if youd be interested in rebuilding..... has 234k miles on it bodys pretty good shape just a bit of rust and a couple dents.... i would like to get $800 if i could.... but its either sell it or get it towed.... damn city laws saying you cant let a car sit at your own house for a period of time..... im hoping to stash it somewhere but hopes not high.... owner tows it themselves... if your interested p.m. me.
 


91gpse said:
ok something came up.... i may have to sell the car in the next month.... if youd be interested theres pics of it on my profile it needs a new motor thats it.... well cam if youd be interested in rebuilding..... has 234k miles on it bodys pretty good shape just a bit of rust and a couple dents.... i would like to get $800 if i could.... but its either sell it or get it towed.... damn city laws saying you cant let a car sit at your own house for a period of time..... im hoping to stash it somewhere but hopes not high.... owner tows it themselves... if your interested p.m. me.
Click to expand...

ok so i managed to come up with enough money to tow it to a friend of mines house and were keeping it in his garage for the winter.... im keeping it till at least spring then if i decide to keep it ill probably start work on the conversion....
 
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