Will a 455 bolt directly to a 350 turbo tranny?

Hi everyone. I need to know if a 455 will bolt directly to a turbo 350 tranny? My gs350 motor said ker-ker-kerplunk. The crank broke and went through the block. So now i have two 350s that need to be fixed. :ball: As the saying goes.....When in Rome..........I figure if im changing the motor, i might as well go with a big boy. :3gears: :TU: Anyway, if its not a direct bolt what kind of mods will i need. And perhaps someone might know where i can find a 455 on this sight? Or maybe someone has one for sale? And what is the expexcted price range? Thanx

 

will bolt up but you will need big block engine mounts. hope this helps

 

350 to 455

Sure will if it is a BOP 350 transmission. If its a chevy pattern only the two bottom holes (one on each side) will bolt up.

 

Yea both are buick parts. Buick 455 and buick 350 turbo tranny. Can I use the motor mounts from the GSX? and if so, will the tranny hold up with such a big engine or will it be an upcoming problem?

 

The TH350 is on the weak side if mated to a 455, but can hold up if not abused.

 

The GSX mounts will work fine, as long as it is a big block car. A GSX could be ordered with a sbb.

 

so what i understand is that i can mount the 455 to the th350 as long as i have big block engine mounts. anything alse i might need to do? Thanx

 

You will need the actual rubber mount that bolts to the block, you will also need the frame pads that mount to the frame for a big block. TA Performance sells both.
The fan shroud is different from the 350 to the 455.
The exhaust will need to be modified.
Throttle cable might be an issue as well as the starter wires might be a touch on the short side.
I would also recomend a new starter. The one from the 350 will work but may be a tad on the weak side.

 

What will i have to do on the exhaust? will the headers be off or just the shape of the piping?

 

Actually I believe the motor mounts are different also, even though they appear to be the same. I have a 350 turbo behind my 455, which is about 390 HP and it's lasted five years so far. Granted it's not a daily driver, but when I do drive it, I'm always driving it hard.

 

Check out George N.'s Buick Performance site - it has pretty much exactly the information you're looking for! :TU:
http://www.buickperformance.com/conversi.htm

 

Swap

I put a 455 Buick in a 350 GS last year. Used TA frame mounts and the engine mounts that were on the 455. New exhaust all the way back. Make sure your flex plate is drilled for 11" and 13" converters. The 350 Turbo in my Buick is doing just fine behind the 455. Starter locations on both engines are the same so the wires are not an issue. Its a fairly easy swap go for it. :TU:
Bob Harris