I bought my 84' Firebird about 2 and a half years ago as my first car, it came with a 400 sbc, 700r4, and a 10 bolt rear end. Since I was still in high school when I bought it I beat the snot out of that poor 400. And it still runs with no major issues, I just get the feeling that its not long for this world. So i'm at a cross road with my engine situation. Would it be at all worth it to build the 400? Or should I just slap in a 350 and call it a day? In a perfect world I would put a Pontiac engine back in it, since thats what it was born with. But I can't seem to find a reasonably priced poncho 400 anywhere. What should I do?

 

Is it consuming oil at all? Smoking on starts? Does it compression test ok on all cyl? Might not need rebuilt

But if you did, have the block inspected. If its a virgin block and in good shape it is likely worth building. If its been built before then cyl walls might be thin. If its already .030 over you will want to sonic check it and see if it cleans up with .010 more bored/honed out. If not and it has to go more it will get thin. Wont know for sure until they sonic check it

 

It smokes, leaks and burns oil. its done that since the day I bought it. My only issue with rebuilding the 400 is finding a good set of cylinder heads with the steam holes already drilled.

 

The way a stock 400 fails, is the crank. It breaks at the front of the #1 rod journal, or under that counterweight. It's a harmonic vibration type of problem.

Yes I've broken some that way.

Definitely check the block and all that; no sense pouring money into something and in the end discovering it won't take it after the money is all spent. But, PLAN ON getting a new crank.

No, your 84 car was NOT "born with" a Pontiac engine. Unless it was a 4-cyl. And you won't get anything any better out of a Pontiac 400 (relic from the 60s) than a small Chevy 400, except aggravation and hassle and expense getting it to fit. Stick with the thing it was "born with", if that was a V8; which is, a Chevy (GM) small block. All around, a better deal than the 60s Pontiac size.

It takes me around 10 minutes a head to drill steam holes. ANY SBC head. Totally not an issue. No need to find some that already have em. But you're probably faster than me anyway; you wouldn't even notice the seconds it takes. Build what you want, get the heads you want, drill em. It's worth it.

 

I ran the VIN, it came with the Iron duke.

 

I have a 400 I just swapped into my camaro. The Brodix heads I put on (ik200) do not require the steam holes be drilled. You just modify the head gasket a little to get the existing hole to meet up with the hole in the head.

 

 

I would guess it is because it is a PITA to fit, you would have to custom make the motor mounts, headers, trans mount, torque arm relocation mount. Find a proper transmission and a bunch of other things. In the end you would spend thousands to gain virtually nothing. There is no logical reason to do a Pontiac 400 swap. These cars all came with chevy motors with the exception of the Pontiac 2.5L 4cyl or Buick 3.8L turbo so not even an originality thing.