This may upset some of you but I have to ask.

I am wanting to put a 454 into my '69 Firebird. I am wondering if this would be a direct bolt in or if I would have to modify the engine mounts. Do I have to modify anything else for this big block to fit?

Have any of you had experience with this that can help me?

A monster 455 will fit better!!

Steve

You will have to replace your frame mounts for Camaro mounts. I think that's all except for the obvious things like you will need a Chevy tranny or bell housing, exhaust manifolds/headers ect.
Jim

Starter wiring will change sides also.

Steve

You'll need a camaro engine harness because the alternator is also on the ohter side of the motor - I think.

Q

Pontiac transmissions/bell housings will bolt onto Chevy engines, but Chevy transmissions won't bolt onto Pontiacs.

I don't know where you got that one Amervo but it's totally wrong. Pontiac transmissions do NOT bolt on Chevy engines unless you have the super rare multi bolt pattern on yor bell housing.
Jim

Don't forget the new emblems.

Cheap shot - I know. Sorry

- Jake

Jim

the Pontiac transmissions/bell housings will bolt to the chevy but only with the four lower bolts the two uppers will not. I know its not right but I have seen a few of them driving around. Me I would not do it.

DruggNet
you can always use an adapter, thats what I did till I got my Chevy trans, and as far as the wring goes you can undo the wire loom and move the starter and Alt. wires to fit, you might have to lengthen them, cant remember its been 25 years since i did mine. Also I see your around San Deigo. I'm in San Bernardino and can come down and help you if you need it. I have a SBC in mine. and if you need a Chevy TH-400 I might part with one of mine. you can send me an E-Mail at firebird69racer@yahoo.com

Wade

I appreciate you setting me straight on this bolt pattern point. Having said that, I have cobbled a lot of things over the years but have never even thought of installing a trans with bolts missing. I want to put my adivce/comments in the context that they were given. When someone asks for advice I believe they should get the correct advice and not advice that is dangerous or just plain wrong. I believe bolting a Pontiac trans with four bolts to a 454 is just asking for trouble that's why I butted in with my rough comment. A Pontiac transmission was not designed to be bolted to a Chevy engine period. Of course, if you have the correct adapter plate you might get by.
Jim