I'm in the midst of a rebuild on the 324 in my 1956 88 due a nasty case of rod knock. After tearing everything down, we discovered the crankshaft is damaged, so I'm looking at sourcing a replacement.

A user on one of the forums here has a crankshaft from a '55, but I wanted to get opinions on the compatibility of that crankshaft with my engine. The other question was whether it matters if my car has the Jetaway transmission, so I wanted to confirm that, but in looking at the transmission, I don't see the badge with the identifying numbers I've seen described elsewhere, so I'm not 100% on that. My car does have park, and I've seen people who say that if it has park, it's a Jetaway, but I didn't know if that's definitive.

Here are some photos of the transmission stamps, which I'm not sure correspond to the numbers I've seen describing the transmission type, but hopefully someone here can help identify it.

I appreciate if anyone can confirm the transmission type and offer an opinion on the compatibility of the crankshaft with my engine.

I'm working with a highly recommend rebuild guy on this who has done many successful rebuilds for people I know over the years, but I wanted to tap into the knowledge base here of people highly familiar with this particular engine.

 

'54 thru '56 exc. "O" HydraMatic, and '56 manual trans and "R" HydraMatic used the same crank, #567443, which included the pilot bushing and retainer.

'56 w/"O" HydraMatic used crank #567943.

Since you've got a Jetaway, which I'm assuming is an "O" HydraMatic since it is not used prior to '56, you'll need another '56 "O" crank, according to the part book. Whether a '54/'55 crank can be made to work, I don't know.

I thought the ID tag was on the side with the linkage.

 

Is your crankshaft not re-grindable ? That would be my first choice. Buying something used is just taking a gamble.

 

From what I can see looking at the transmission, I can’t locate the tag, so based upon what I’ve described are you saying it is definitely a Jetaway?

My engine guy does a lot of machine work in his shop and said it might be possible to repair, but he suggested that it may need to be replaced, so I’m looking at that option right now. I’ll clarify with him that it’s the best choice next time we talk.

Thanks to you both for your input.

 

If your car has Park (P) on the shift indicator, it is a Jetaway. In 1956, the Super 88 and the 98 both used the new Jetaway. The regular 88 continued to use the slantpan hydra-matic.

 

I do have park. Just wasn’t sure if that was definitive. I always thought I had the regular 88, but I’m starting to wonder if it’s actually a Super 88. I have the 4 barrel carb as well. I don’t have power steering or brakes, or some of the trim items I’ve seen mentioned from the Super 88 like the padded dash. I do have chrome trim around the windows and vinyl headliner with chrome bows.

Still not sure if the crank from the ‘55 is going to work, but I’m going to go back to my guy and revisit the idea of repair before I try something that may not work.

 

Pretty sure you have a Super 88. The Super 88 had the same engine as the 98 with the 4 barrel carb. The trim was a little nicer. Power brakes and steering were options and many did not have them. Padded dash was also an option.

 

That sounds right. Thanks.

 

If you post the body style from the Fisher Body data plate we can tell you what you've got.

 

Here's the tag with those details.

 

56-3639SD = Super 88. Base 88 would just be a 56-3639.

 

Thanks everyone for the helpful information. I've learned a few things on this thread, which led to some other searching, so I wanted to add a few things here in case it's helpful to anyone in the future. If I have stated anything inaccurate here, please correct.

Now that I've learned I have a Super 88 and not a base model, it's clear that I have the Jetaway transmission. So the main difference that I can tell from the '55 camshaft and the '56 is the presence of a bushing on the '55 that allows for the interface with the older style slant pan transmission. Since the camshaft on the '56 bolts to a flex plate, not directly to the flywheel, that bushing doesn't interfere with anything, so no modifications should be required. Modifications for the reverse would be required, that is to pair a crankshaft for a '56 with the Jetaway in a '55 with the older tranny, specifically to bore the crankshaft to accept the busing

For these reasons, I don't see any reason why the crankshaft from the '55 wouldn't work in my engine. Unfortunately, we have approached several machine shops about repairing the current crankshaft, but they've declined. I'm not sure exactly why, but if it can't be repaired, it seems like putting the '55 crank in my engine is a good alternative.

I appreciate the helpful input in sort this out, and I've misstated or left anything out that's important, please add to this.

Attaching a few images that could also be useful for those looking at similar projects.



'56 crankshaft flange



'55 crankshaft flange



'56 Super 88 flywheel



'56-'60 Jetaway flywheel assembly



'55 engine internals

 

If they can't grind your crankshaft, I doubt I would take any other work to them ! ! !
Since you don't at least have the state you live in, in your profile, we are not able to suggest people from an area near you.

 

Sorry, about that. I'm in Rochester, NY. I just added my location to my profile. If you have suggestions of machine shops who do this work in my area, I'd appreciate it very much!