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Does anyone know if a 1956 V8 Twin-Ultra trans will bolt up to a 1954 straight eight block?? Will the 1954 bellhousing bolt up to the V8 trans? Will the starter be properly aligned if I do that? Someone out there must have tried this already and I hope they read this forum

I always thought the bellhousings were completely different.

The closest thing you are going to get to a 'Twin' on a '54 block would be a 'Gear Start' I would imagine.

There are not very many 'Gear Start' trannies out there as they were really protoype trnasmissions installed at the very end of the '54 production run. My Clipper does have one of the them. You can spot them easily in a '54 by the dipstick visible under the hood on the drivers side, or the fact it has two drive indents (one before and one after the 'D') on the shift selector.

I think a trip thru the parts books is in order. If a '54 gearstart transmission has the same bellhousing part number and flex plate as a 55 Twin, I think you would have reasonably high confidence they'd interchange at the front end. Might still have to do a little checking to see if the driveshaft numbers are also the same.

Just checked, bell housing and driveshaft numbers are different. Doesn't mean they won't bolt up but certainly something is different.

I know that Sierra Grove Packards, who makes the TorqueFlight conversion adapaters for the Packards has two different kits. One for the 54 and prior, and another for the 55/56. So I would imagine that they are very much different.

Eric may be able to give more detail as I know he has owned '53s and '56s.

The difference is the size of the converters, the pre-'54 (I can't honestly say about the Gear Start, never seen one) converters are a larger diameter than the V8's, it won't even go into the extended bell of the V8. I tried to put an Ultramatic off of a '51 behind my 320, nope, no go. Also, the straight eight flywheels are too big for V8's on the automatic side, and too small for V8's on the manual side. The 1954 Gear Start may the exception, though. It may be possible that the bellhousing and front pump assembly will bolt up to a '55 or '56 Ultramatic. I couldn't tell you without seeing them side by side. I never did try my '53 Ultramatic, I just assumed it was the same as the '51 tranny I found behind a running 288 in a local junkyard that I grabbed.

I thank all of you for your input. I guess the first thing is to see if a 55-56 torque convertor will bolt up to a 54 flexplate, and if a 55-56 bell housing will bolt up to a straight-8 block.

Big Kev mentioned that Sierra Grove Packards has kits for prior 54. You mean the straight 8's, right? I'd be interested in any contact information on that. Thanks

If you're looking for transmission adaptations to straight eights, follow me closely on my hopefully new project, or catch me in the chat and I'll explain more.