Chris10an

iTrader: (1)

Is a 1978 Pontiac 400 engine an GM engine? Is it a smallblock/bigblock?
Is it possible to bolt an transmission from this engine over to an LS1 engine?
I know it is a own forum for Pontiac, but I'm not a Pontiac enthusiast, I'm sure someone on our own forum know

Najania

Yes it is a gm engine. but not a chevy..

It's actually called a mid block since they have no small or bigblocks in the pontiac division.

And it is not possible to directly transfer the transmission from that engine to a ls1.

cambirdracing

iTrader: (4)

^^^ correct. pontiac's had one external dimension excluding the 265/301 (we don't consider those to be anything) on all v-8's. You can use the tranny BUT you need to buy an adapter plate, depending on the tranny. The bottom holes are the only two that line up. You can take a 455 crank and turn down the mains and bore the 400 block .030 over and have you a 455 in the 400 block. And the best part is that no one will ever know.

EPP

iTrader: (22)

http://www.exoticperformanceplus.com...html?item=1331
Lunati camshaft for Pontiac engines.

http://www.exoticperformanceplus.com...html?item=1650
Holley mechanical fuel pump.

Just in case you decide to keep the Pontiac engine, the above items are at a deep discount. Bob

DarkJuggalo

iTrader: (6)

most people consider it a small block, i had a buddy with a 400 all worked up in a 86 iroc, and that sucker was evil. they make gobs and gobs of torque, go with a th400 behind that, he tried the 700r4 and after having it rebuilt the 3rd time he stepped up to a th400

cambirdracing

iTrader: (4)

NO they don't, you are thinking of a Chevy engine. Well, then again, Pontiac are in a class of there own.

ici8uup

the only problem with chrises mill is that poor 78 smogger prolly has 6.5.1 compression at sea level lol mill .60 offf the heads and wake it up a bit for the price of head gaskets

cambirdracing

iTrader: (4)

They came with either 7.8 or 8.1 depending on the head.

retardedpenguin

iTrader: (2)

78 Blocks are no good for performance if it is a 557..

baalic

iTrader: (8)

I had a chevy 400 in my old Nova, and they do make HUGE amounts of torque. Mine had head work done, an aggressive cam, true dual's, edeilbroch 750 4bbl and Edeilbroch intake to list a couple mods.... Guy we bought the car from had it dynoed around 450 to the wheels for hp but not sure on the torque, but at least 400+....... It was a fun little Nova but it didn't feel as fast as my LS1 because without drag radials, all you would do is peel out, even from about 60 if you punched it.... Thanks to the Stall and the Race built TH350...LOL

demonpixel

iTrader: (19)

There is no such thing as a small block Pontiac. The Pontiac 350, 400, and 455 are all based off of the same block.

I have a Pontiac 400 in my 72 Firebird. I can't stand that damn engine. I'm building a carbed LS1 for it now.

The Pontiac TH350/TH040 transmissions are a BOP style transmission. They will not directly bolt up to an sbc/LS1. Summit makes an adapter plate that is supposed to allow you to bolt it up though. I just got one so I'll find out how well it works in the next few weeks.

Jetfan73

i have a 78 Formula restore and want to put a LS1 in it. I know about the tranny plate but can anyone tell me about changing the motor mounts
Thanks

cambirdracing

iTrader: (4)

78 Formula's are harder to come by. You would be doing it a disservice by putting a "Corporate" engine in it. plus if you put a LS in it, it's technically not "restoring" it.

Bob@BruteSpeed

iTrader: (16)

You should be able to find LS1 mounts for 2nd gen Camaro's (F Body) as the LS1 swap is becoming increasingly popular. The 2nd gen Camaro (1970-1981) motor mounts will bolt right to your subframe. Bob

violent_celerity

the chevy 400 and pontiac 400 are completely different motors.. almost all SBC's make alot of torque.

F-Body Lover

keep it poncho

samsdad

iTrader: (1)

Keep it Pontiac.
I've had several Pontiac 400 v-8's they are torque monsters. If GM hadn't stopped building the "Pontiac" engines around 80 they would have evolved to an even better motor. Just look at the SD455's. LS motors are great too, I want to put one in my 2000 v6 Convertible.
Samsdad

retardedpenguin

iTrader: (2)

Mine was a 78' 400 but it was a W72 engine. It had a nice cam, headers and mild head work. It would hang with my 99 Trans Am and I beat an 05+ GT easily. Sucker hauled ***.