mrobvious34

Hey guys i have a 77 trans am that was my first car and im looking at droping a new motor in it but i cant decide and what motor. I am thinking LS1 (4L60 or t56 depending on my budget) or rebuild the 400 with a 700r4 swap. The ls1 has the dependablilty, and modern restorod style but the 400 would be more true to its roots. What do you guys think?

this is the car

mrobvious34

this is the inside and under the hood too

OldSchoolFormula

If its an original 400 car I can see the debate. With a set of KRE heads, a roller cam and one of the new Holley/FAST/MSD fuel injection kits the old 400 would run pretty damn well and would be great with a T56 or a 700r4/200r4.

Tough spot to be in.

LXinMS

iTrader: (58)

I'd leave well enough alone.

Find an old tore up car to hack on.

turbinesurgeon

Same, I would leave that one be. Besides, "If" you decided to sell it, you would be off to a good start funding an LS1 swap on an "old tore up car"

bronx_peanut

I swapped mine and love it. Your Trans Am is really nice though.

Black00Z

Tough choice, but I say keep it original.

VandykeT/A

What heads are all ready on the 400? They don't look like the old 6xs. If you plan to ride it alot or want to make big power I'd drop in a LS but if its going to be a every now and then car stay 400. Those 400s like fuel lol.

95camarslo

I think you should stay with the 400 and rebuild it. You can make good power out of it, but you will use more fuel! The 400 just looks a lot better under the hood than an LS.

Cecil07

I have been pondering the same thing... but... mines not number matching... and a 77 clone... so... i think the LQ4 is going in...but with a 700r4 that i have had built for the 455 already in place...hoping the seat of the pants feel is the same...

Doug G

If you car is numbers matching....save the take-off parts for later in life.

2nd Gen Fl 'bird

iTrader: (13)

This^^ exactly. You don't see too many that are that "intact". Super clean car. I think you would eventually regret it, especially since it was you first car.

nobreaks254

iTrader: (50)

keep the poncho in it.

Goldhawg

iTrader: (7)

Easy choice....swap in LSx power! But the real answer is do what you want to do, not what you think others would want. As for future resale, I can't imagine a nicely done conversion wouldn't be at least as valuable as an original. While you don't see that many T/A's anymore, they weren't exactly limited production, and w/factory power levels were not all that desireable (IMHO). You decide!

Rick Speed

iTrader: (55)

I would swap in a LS and keep all the original parts incase you ever sell it

murphinator

iTrader: (2)

I am in the same spot with my TA kind of - yours is a much more original car so I can see it being a painful decision for you.

mine is an 81 that was a turbo car with a 72 nose so its a mongril but really rust free , the 400 in mine is of unknown origin and I just listed the complete engine with headers ,high rise , edelbrock intake and turbo 400 locally on CL as well as the turbo wheels & tires.

I am going year one 17" billet honeycombs and likely something LSX , my thought on that is I could pull the 400 and nowadays you can buy aftermarket crank & rods for about the same price as aftermarket crank & rods for a sbc now that eagle & scat are making stuff , it would be a lot stronger than even the best stock castings and make plenty of power but at the end of the day its still going to be a heavy **** fuel pig of an engine so I said screw it and listed the drivetrain knowing once the engine bay is empty i will commit to buying up the necessary goodies to bring the car into the 21st century engine wise

good luck making your decision , just keep everything so you could go back if you regret it allthough I doubt you would

Black&White

If you're never planning on selling it then do what you will enjoy most. If you want to have a better driver then definitely go with an LSX, although I'd do a 402 stroker so at least you're in the right ballpark on cubes. If it's not the original 400 then it's easy, LSX swap. But if you rarely drive it and it's matching numbers I'd probably leave the 400 where it is.

mrobvious34

just going thru my old threads and forgot about this one. Since so may years have passed since i originally posted, i thought i would update. The car is not a number matching car, if it was i would have left the original motor. VandykeT/A asked about the heads on the old motor, you are correct they are not the 6X, they were 1970 #16 heads. I did not go with an LS but rather kept the Pontiac a Pontiac. I ended up with a Butler Performance 468, full roller, with edelbrock aluminium cnc ported heads, ceramic dougs headers, torker intake, and an msd ready to run distributor