will it mount up?

[73redblaze]

so my bro-in-law has a 68 firebird with a 350/th350. he blew the motor and its been sitting for about 2 years now. well hes birthday is coming up so i figured i buy him another cheap engine for it. (hes lazy). I was going to get him a cheap Chevy 350 but after talking to him he says he REALLY wants to stick with a Pontiac motor. so after further investigation I found him a 1979 402 out of another firebird. I don’t know how big of a PITA it will be to swap over. I asked the guy for specs on the 402 so i will be posting them soon. what all will i need to change? and is the 402 considered a bb or a sb? if its a sb can i still use his headers, carb, ext? Thanks guys

 

[toomany]

{I re-read the post, so ignore my first sentence or two}

I'm not up to speed on my 1st gen Firebird motors (if it's stock). Does it have a Chevy 350 or a Pontiac (or Olds, Buick) 350? If it's a Chevy 350 then his transmission will not bolt up to the Pontiac 402. If it's a Pontiac motor in there already then it will bolt up to the transmission. I'm guessing that the motor mounts will be in the same place too (could be wrong on this though). Unless he has a dual bolt pattern transmission...then it won't matter what motor he goes with, it'll bolt to most any GM v8.

So to sum it up. Buick, Olds, Pontiac, Cadilliac motors share the same bellhousing pattern. Commonly refered to as BOP. Chevy's (SBC and BBC) have their own pattern. There are adapter plates to allow one style to be used with the other.

 

[onetonjimmy]

No such animal as a 402 pontiac unless the owner possibly had the 400 honed out slightly ( or 389 bored a lot) and is now calling it a 402. Could be a chevy bbc (aka 396 depending on the year of the motor) Regarding motor mounts- it really depends on what motor/year because pontiac made some blocks with a "universal" application and others would not fit unless you used an aftermarket adapter. all pontiac blocks except the 265/301 are dimensionally the same so his acc. would work.only exception would be the old 389/421 and pre '64 stuff but all that stuff is pretty rare nowadays.

 

[GMC1977]

with old pontiac motors there is no difference between big block and small block. if you took a tape measure and measured around the block they would come out to the same meauserment. and the 402 would be a .10 or .20 bored over pontiac 400. ( veryy nice motor and verrrry rare)

 

[73redblaze]

yea shes a pontiac 400 slightly bored over from what he says. I e-mailed him asking for the block and head #'s. no reply yet but i know him personaly so i could always just drop by.