Pontiac 400 or 455 build help

[rocket dawg]

Sorry guys, the 301 trans wont accept a 400/403 or the 455. I tried this years ago. I had a spun bearing in my 79 301 4bbl. T/A ( 155 amazing HP!) wow. So my options were another boat anchor 301 to which nobody made any aftermarket parts for or a 400 or 455 and get another transmission. I just happen to have a healthy 400 SBC on a dolly in the back room so I needed a turbo 350 from a donor camaro with some other parts --- A/C brackets, motor mount etc.. My friend had a 400 pontiac he wanted to sell me, it needed a rebuild, so we compared the 301 to the 400 and they are different. I pulled the 301 trans and even tried to slide it to the 400 and its a no go. At the time there were no adapters and I dont believe anyone has ever made one but I havent explored that. The 301 had a turbo 350 trans but a one of a kind bolt pattern. The cross member for the 301 trans will work on other transmissions and so will the drive shaft.

 

[hoppin5478]

Sorry guys, the 301 trans wont accept a 400/403 or the 455. I tried this years ago. I had a spun bearing in my 79 301 4bbl. T/A ( 155 amazing HP!) wow. So my options were another boat anchor 301 to which nobody made any aftermarket parts for or a 400 or 455 and get another transmission. I just happen to have a healthy 400 SBC on a dolly in the back room so I needed a turbo 350 from a donor camaro with some other parts --- A/C brackets, motor mount etc.. My friend had a 400 pontiac he wanted to sell me, it needed a rebuild, so we compared the 301 to the 400 and they are different. I pulled the 301 trans and even tried to slide it to the 400 and its a no go. At the time there were no adapters and I dont believe anyone has ever made one but I havent explored that. The 301 had a turbo 350 trans but a one of a kind bolt pattern. The cross member for the 301 trans will work on other transmissions and so will the drive shaft.

Thanks for the heads up, I have no direct experience with the 301 and was going off what I could find on the internet (we know how reliable that can be) and my experience with other various Buick and Pontiac motors from the 70's and 80's. I have never run in to anything on those motors they wasn't BOP or the dual bolt pattern. I have some left over TA parts and a 400 I want to throw on an affordable base model firebird (likely a 301 car) so ill know to stay clear of the 301 tranny, or at least plan on swapping it out when looking for a donor car. It looks like some of the 301's, starting in 80, came with a th200c as well which weren't super durable.

 

[Damon]

rocket dawg- so what bolt pattern is it? Chevy? It seems unlikely GM would have designed a completely separate bolt pattern just for the much-unloved 301, also making the transmissions that bolt to the back of them one-off designs as well.

 

[rocket dawg]

I was mis informed. According to other sites it will bolt up to a 400 Pontiac. The engine we tried to mate it with must have been something other than what I was told.( 389?) I'm going off memory and quite a few years ago. Some of the mounting bracket differ from 301 to 400 i.e p/s and alt. Had I known this, I may have dropped a Pontiac 400 or 455 in my car. But I pitched the trans ( still good) and engine ( not good) and went with the bowtie. Sorry for the wrong info, I'm mad at myself for not doing enough research back in the day. I'm happy with the 406 in the car, but getting the shaker on and the hood to close with a semi high rise intake was a chore. The 301 2 bbl resembled a quadrajet but the back 2 barrels were missing. weird. The 301 was a lightweight economy engine built for the energy crunch of the eighties. I drove it for years and it had a hard time getting out of its own way (2.73 gears) but 23.9 mpg best on highway--- uhmmm but the speed limit was 55 back then..

 

[Damon]

Appreciate the update. When you suffer from early-onset old-age like I do it's nice to get the occasional confirmation you haven't lost all your marbles just yet.

That carb you're talking about is the Rochester DualJet. Some early ones were even cast with the full secondary stuff from the QuadraJet still there, but it was just solid aluminum- no secondary throttle plates or air valves up top! Within a year or so they turned it into it's own 2-bbl variant of the QJet which was, as you observed, the front 2 barrels of a QJet with the secondary stuff sort of lopped off the back side and using a weird semi-trapezoidal shaped air cleaner flange.

Now THERE is a carburetor I wish I could forget! Sadly, when you get old only the useless trivia stays. All useful information is systematically purged. It's like my Grandmother once told me..... wait, what the hell was it she told me?? Ah, **** it. Must not have been important.

 

[Cataldo]

My buddy just fired up his new 455. It is 9.8-10:1 with ported big valve heads and a stout hydraulic roller cam in it from Howards. It sounds great and runs wonderful, he is tickled pink about it.

We are expecting 425 hp and 500+ lb ft.