1967 Lemans Convertible BBC/TH400 Swap

[gcwryan]

So long story short, my dad has had the car since he was 16, (51 now) It's been sitting since I was in diapers (26 years ago)
Old setup was pulled back in the day, in 2008 he got a freshly built 396 BBC/TH400 setup to swap into the car.
Life got in the way and fast forward to now we're finally wanting to get it going. I've been doing some research on here
but can't find much info. I guess I'm just asking for any tips/setups for Motor Mounts/Transmission cross member/Driveshaft length.
We're trying to to just get the new setup mounted in the car for now and go from there. I just haven't found much info searching around.
So any help would be appreciated!

[b-man]

You should able to use reproduction BB Chevelle frame stands and engine mounts along with Chevelle headers.

The trans crossmember that Pontiac used for the TH400 is in the correct location. The driveshaft from a ‘67 GTO which was the only Pontiac A-body in 1967 to come with the optional TH400 is what you need.

Dimensionally the Chevy and Buick/Olds/Pontiac (BOP) short tail shaft TH400s are the same other than the bellhousing bolt pattern.

Keep in mind the fuel line along the frame is on the opposite side on Pontiacs and the battery tray is as well compared to a Chevelle. In fact the wiring harness needs a lot of work to go from a Pontiac V8 to a Chevy V8, pretty much everything is on the opposite side.

Good luck with your project. If this was my car I’d seriously consider selling the BBC and buying a Pontiac 400 or 455 that’s 100% a bolt-in proposition, getting that Chevy engine in place and playing with all the things necessary to make everything work can nickel and dime you to death.

Just because you already have it doesn’t mean you have to use it. :)

[gcwryan]

You should able to use reproduction BB Chevelle frame stands and engine mounts along with Chevelle headers.

The trans crossmember that Pontiac used for the TH400 is in the correct location. The driveshaft from a ‘67 GTO which was the only Pontiac A-body in 1967 to come with the optional TH400 is what you need.

Dimensionally the Chevy and Buick/Olds/Pontiac (BOP) short tail shaft TH400s are the same other than the bellhousing bolt pattern.

Keep in mind the fuel line along the frame is on the opposite side on Pontiacs and the battery tray is as well compared to a Chevelle. In fact the wiring harness needs a lot of work to go from a Pontiac V8 to a Chevy V8, pretty much everything is on the opposite side.

Good luck with your project. If this was my car I’d seriously consider selling the BBC and buying a Pontiac 400 or 455 that’s 100% a bolt-in proposition, getting that Chevy engine in place and playing with all the things necessary to make everything work can nickel and dime you to death.

Just because you already have it doesn’t mean you have to use it. :)

Alright Thanks for the info so far brother. I'll use this crossmember, I believe i've read multiple places for the 67 gto driveshaft it's 59.375" center to center. So that's what I'm thinking I'll need. Yes we have the fuel lines/battery tray moved around already. Still need to mess with some wiring. My dads is 100% wanting to go with the BBC/Th400, he bought it freshly built from his buddy who retired from engine building and he doesn't really want to try to sell this setup and find a reputable shop for a new build.

[b-man]

All good.

My LS3/4L70E swap into my ‘64 Tempest was/is a royal pain. I wanted a lightweight V8 engine with EFI and an overdrive automatic and that was really the only economically feasible route to get that. Sometimes wish I would have left the original 215 (Chevy based) six cylinder in it but……430 hp beats 140 hp any day and both consume about the same amount of fuel doing that.

Good luck. :thumbup:

[gcwryan]

All good.

My LS3/4L70E swap into my ‘64 Tempest was/is a royal pain. I wanted a lightweight V8 engine with EFI and an overdrive automatic and that was really the only economically feasible route to get that. Sometimes wish I would have left the original 215 (Chevy based) six cylinder in it but……430 hp beats 140 hp any day and both consume about the same amount of fuel doing that.

Good luck. :thumbup:

Hell yeah man sounds like a fun little cruiser.
Here’s my 2006 GTO. My buddy built it at his shop.
408 stroker, 2650 supercharger, th400 and a SRA swap!

[b-man]

Beast!