Technical Jimmy 302s and Hydramatics?

Hi all.
I have a 1948 Poncho with the 239 flat six backed by a Hydramatic.

I fell into a killer deal on a fully rebuilt 302 inliner.

Its a ways out, but when the time comes will the 302 bolt up to the Pontiac tranny? This 302 has a massive bellhousing and flywheel. What are the chances of the pontiac parts swapping over?

My $500 fully rebuilt Jimmy Six

 

I have a hydro adaptor starter and flywheel from a 235.
Don’t know if that will help
The hydro experts know

Might want to add gmc to the thread title
I thought you were asking about a ford V8

 

Looks like you might have a military 302. They used hydramatics. Look for a mechanical fuel pump. If there's no place for one it's military. They used electric.It looks like you have the 24 volt sealed ignition too.....probably the military 302.
I'm told the chevy bell housings from 216 , 235 , 261 will fit but not sure about the Poncho flat 6

 

Army truck stuff is different from the block back - nothing there you want, anyway. You really want to use a '52 - '55 dual range trans, as the '48 single range has drawbacks. '53 - '59 GMC or '54 - '59 Chev 6 hydro parts are what you need, preferably '55 up for open driveshaft & 12 volts. And get all of it - linkage is a bitch ....
As a matter of fact, it's going to take a GMC flywheel/torus to make this work. The Pontiac torus bowl won't fit the GMC flywheel.
Bear in mind, many other HAMBers know more about this than I ...

 

This will be interesting to see how this turns out. When I was in high school in the fifties, I'll bet half of the early fifties Pontiac's I knew of had Oldsmobile's/Hydramatics in them.

 

I read that 70% of all Pontiacs in 1948 were Hydramatic equipped

 

A lot of GMC 6 pickups had hydros stock 55-56. Not sure on the ones up thru 59. 270 would be the best because the later ones had the 6 hole flange. A search should find one removed for a SBC-BBC.

 

Hillbilly:
Not surprising. Pontiac production was sold long before the dealers received the car, so why not load every car with accessories ? First 3 years after the war, everything every maker produced was going to be sold. Dealers further profited by adding more upon arrival. In the '60s & '70s, these cars had no interest - I stripped half a dozen costing anywhere from $25 for runners to some " haul the damn thing off - what the hell you want with that thing ? " ones. Just about every one had B-31 backup lights, Guide fogs, that beautiful Guide 600? chrome turn signal switch, several heaters, the radio that fits Chev & GMC pickups, rear window wiper, emergency brake warning whistle ... and all those bumper guards. I don't remember but one that wasn't an 8 cyl. hydro ... most died of overheating or trans failure - both are from neglect.

 

Good point. Thanks

 

cool....not sure what the trucks were running behind the poncho's.....

 

They [55 and 56] were running a Pontiac 287/316 V/8 with dual range hydramatics or manual transmissions.

 

Pics of the car for the bump.

 

I think i found my dual range trans

 

save that bumper and trim too!

 

Ive started the search for the parts i need. I have some questions.

Am i looking for a flexplate or a heavy flywheel? My pontiac has a flywheel, but I've seen dished flexplates online

It looks like i will need to use 2 bellhousings. One on the block (likely from a 235) Then a second one to the tranny (hopefully can use the one from the Olds if i get it) Am i correct?

 

Like this?

 

Maybe? Hoping someone else will chime in

 

Are ya getting all of that parts car?
That front bumper and grill looks cool

 

Im working on it. Someone told me to get it out of there, but as it turns out it wasnt on their property...

Rear bumper is there and in good shape. Motor is intact and has clean oil in it. Rear end present also. It could have all i need accept the GMC parts

 

Can someone tell me if this will work? It is from a 1957 step van.

 

It is a Hydramatic Torus cover & adapter, but I have no idea if it would fit your 302. One thing is that the starter for the one you show, (if you were using that Chevy 6 engine in that pic), needs to be from a Hydramatic, and from a 6 cly Chevy/GMC.

I sold 58 Postal Van Hydro stuff from a 235 on Ebay years ago, and the people who send me questions, said a 283 V8 hydro starter is not the same as a 235 6 Hydro.

.

 

GMC parts and Chevrolet parts won't mix. The GMC flywheel flange bolt pattern is much bigger & torus bowl has 18 bolts vs. 30 some on other hydros.
Chev V8 starter has 3 bolt flange, 6 uses same starter as PG 6 car ...

 

I took some measurements today.

30 bolt holes for the torus. 145 tooth flywheel. 14.5 inches across.

The military engine plate has an opening of 15 3/4". The only reason i measured it all today is because the more i walk past it the more normal it looks compared to other bells ive been seeing.

 

http://topclassiccarsforsale.com/gm...-hydramatic-automatic-1-ton-truck-248-54.html
Here’s ya one in Missouri

 

http://www.2040-parts.com/gmc-248-f...s-cover-trans-mount-plate-very-rare-i1433735/

 

Dang. For those prices i could put a 700r4 behind this thing.. not "traditional" by any means though.

At some point you gotta step back ask yourself if its worth doing

 

Yep

 

I have a 6 cyl. to hydro adapter, 168 tooth flywheel 14" in dia. and flatpan dual range hydro out of a 56' Chevy pickup. Will any of this help you?

Art

 

Thanks for the offer Art. Im slowly going through all the steps now figuring this out.

I was just under my Pontiac and measured up the flexplate. It is the same tooth count, and same 30 hole torus mount pattern. I cannot be 100% certain until i pull it out bit it also looks to be the same 14.5" diameter... my electrical guy says it is possible to convert the 24v starter down to 12v if i had to.

Finding a dual range hydro isnt going to be all that hard. What was worrying me was finding the 30 bolt torus. Until now anyways.

Next question; are the torus the same between the early ones and the dual range trannys?

 

Is this an open tailshaft version?