Hot Rods Pontiac 389 transmission options

So I just picked up this 389 out of a '65 Grand Prix for everyone's favorite price. I was curious what my best bet would be for a transmission. It's going in a '27 T sedan. I'm not sure if I want an automatic or to shift gears myself. Any suggestions??
Thanks -Andrew

 

If three pedals are in your plan and trying to stay "period" Pontiac, the Muncie or Borg Warner T-10 four speed would be my choice.

 

A '65 Pontiac will have what is considered to be the regular, normal BOP pattern. Any garden variety transmission that came behind a Buick, Olds, Pontiac or Cadillac will bolt to it. That includes auto and manual.

No matter what tranny you go with, you will love that little Pontiac.

-Abone.

 

A 65 389 will bolt up to a 200-4R. Thats what I'd go with.

Gary

 

Your member profile does not indicate your sexual "identity".
I always say play it safe & go manual

 

You have to be certain that your block has the provision for the starter to bolt to the engine block

 

Yes, double check that. A 1965 block SHOULD have starter bolts in the block, but doesn't necessarily mean does.

-Abone.

 

My understanding is that essentially all of the 64 blocks are drilled for the block mounted starter, so if yours is a 65 for sure, should be no issue.

 

The '64 I parted out had the ear and holes. 65 up are standard BOP and I'd be shocked to find one that exists without a block mounted starter.

 

As I previously posted a 65 and up 389 is a bolt on.

Gary

 

Don't be a vagina, use a manual transmission.

 

Its my understanding that the 55 thru 60 all use the same bellhousing. and the 61 thru 64 use a different type . and those are all bell housing mounted starters. and the 65 and later use the BOP and is a block mounted starter. pictured is a 56 flywheel and bellhousingl

 

Yep, 65 and use BOP.

 

55-60 will accept the same bell housings but the 55-57 bell housing is not the same as the 58-60 and is not really desirable as it will not accept modern transmissions like the Muncie, t-10, modern 5/6 speeds, etc.

 

It has to be drilled. The starter didn't bolt to the THM 400. We know that much.

 

Since the super hydro (jetaway) for the big cars was done in the 64 model year, there should be no 65 blocks that aren't drilled & tapped for the starter.

 

Yes however the 56 gears & tailhousing can be installed in a 38 buick case and use the top floor shift.https://www.jalopyjournal.com/forum...ars-tail-housing.1095970/page-2#post-12518374

 

Thats why my 60 Bubbletop has a 1965 rebuilt and .030 over 389 as its a bolt up to a 200-4R out of a Grand National. $1600.00 later for a rebuild and its good to go. 75 MPH @ 1800 rpm's sure helps the gas mileage.

Gary

 

Just to be clear in my mind... Are you saying the 55-57 bell is the one that is "not really desirable as it will not accept modern transmissions like....."?

If so, then is it because the "trans side/back side" has a different bolt pattern or is it weaker or both?

 

The trans back side only accepts the Pontiac trans. Its not weaker than the other. However the 55 thru 57 GMC truck Pontiac bell does accept the 318 Muncie and later GM transmissions.

 

Now I really confused. Sorry.

I guess what I looking to know is this: Which year range of bell housing accepts the "...Muncie, T-10, modern 5/6 speeds, etc."?

AND

When you say "55-57 GMC truck Pontiac bell". Is the truck bell different then the passenger car bell for manual trans?

Thanks...I just want to make this crystal clear in my thick head.

PS: Sorry, don't mean to hijack the thread....

 

1955 thru 59 GMC trucks Used Pontiac V 8 engines. and the ones that where standard shift used the 318 Muncie 3 speed or the SM 420 granny four speed. Those truck bells will accept Muncie ,Saginaw , t10 and other later GM transmissions. The truck bell has two mounting pads one on each side.

 

Since you have a 65 motor, why all this discussion about the earlier bellhousings? Just get a 65 or later bellhousing from a v8 tempest, lemans, or gto and be done with it. The 55 thru 64 bellhousings either won't work with your 65 at all or at least have issues of some kind. The 65 and later V8 bellhousings eliminate all that crap.

 

Why all this discussion? Well others that are not the OP ask questions in a attempt to be more knowledgeable. Its certainly not taking any nickle's out of anyone's pockets to discuss all the variables.

 

Thanks Old Wolf... twice over!

 

Ok, fair enough. Just as a final comment, the only bellhousing that will bolt up directly to the 55-60 blocks and accept the later modern transmissions is the 58-60 bellhousing (car) and the mumber cast on that bellhousing is 528820. Dont know about the GMC GMC bellhousing interchange. I do know the stock fork for those is different than for cars. Rocky is up on the GMC stuff as I believe he used that bellhousing on his coupe build. The 56-57 Pontiac std trans is ok for putzing around but will not take the abuse of a performance Pontiac V8.

 

I reciently sold a 55GMC pickup. It has a factory 287 Pontiac engine and a 318 Muncie three speed trans.

 

some of the early gto 's used ford top loaders 3speed?

 

GTOs with 3 speeds? Never seen one.

 

you guys were puttting all this info on mid '50s trannys and bellhousings on here for me! I needed that info and here it is at the right time