[ponyakr]

Originally Posted by louis1

Im looking at putting in a 455 motor in a 78 Firebird who has its original 231 V6 (i think its a Buick )motor in it, will this swap be problematic ?

Im expecting to have to put in a bigger radiator, stiffer springs.

What should i do for motor mounts?

thanks,

Louis

It's just work. I swapped in a 455, where a 305 sbc was, in an '80 Bird. The motor mounts have to be moved to a different set of holes. Don't know if they are the same, or not, They're cheap. So might as well go with new ones, anyhow.

You'll need the motor mount brackets that bolt to the block. They MUST be for a '75-'81 Bird with a Pontiac V8. Originals have gone up to a ridiculous price. Many have been on Ebay for $150 & more. An area guy who sells stuff on Ebay says he has been able to sell every set he can find for at least $100.

They recently began to sell repros, for just over $100. So, you can probably find a used set from somebody on this forum for less than $100.

https://www.firebirdcentral.com/75_8...p/enc-2212.htm

The clamshell frame mounts come in all price ranges. These are probably the cheapest Chinese mounts, which is what I bought. Better quality mounts are sold.

https://www.rockauto.com/en/parts/an...tor+mount,5552

https://www.summitracing.com/parts/a...model/firebird

DS mount upper bolts are real hard to get to. I bought a tap, threaded the holes, & screwed in oversize bolts. If I had it to do over, I'd probably cut a hole in the frame, so I could install nuts on stock size bolts. Would only take a hole big enuff to get a box end 9/16 wrench thru. For some of the bolts, you can use long extensions to install 'em from the bottom.

Here are some posts from my thread about bolting in the mounts. Some of this info might help you.

http://forums.maxperformanceinc.com/...8&postcount=26

http://forums.maxperformanceinc.com/...0&postcount=29

http://forums.maxperformanceinc.com/...4&postcount=30

http://forums.maxperformanceinc.com/...3&postcount=31

http://forums.maxperformanceinc.com/...9&postcount=32

http://forums.maxperformanceinc.com/...7&postcount=33

http://forums.maxperformanceinc.com/...9&postcount=34

http://forums.maxperformanceinc.com/...0&postcount=35

http://forums.maxperformanceinc.com/...6&postcount=36

http://forums.maxperformanceinc.com/...5&postcount=37

http://forums.maxperformanceinc.com/...2&postcount=39

http://forums.maxperformanceinc.com/...7&postcount=40

http://forums.maxperformanceinc.com/...4&postcount=41

http://forums.maxperformanceinc.com/...3&postcount=42

http://forums.maxperformanceinc.com/...0&postcount=43

http://forums.maxperformanceinc.com/...6&postcount=44

http://forums.maxperformanceinc.com/...8&postcount=45