I'm currently putting together a parts list for a 383 stroker I'm building. I've got a late model 1-piece, 4-bolt roller block that I'm going with. I'll be using fully forged internals, and I'd like to be able to transplant my investment into an aftermarket block if need be some time in the distant future.

I'll need a 2-piece crank if I ever go with an aftermarket block, so I plan on purchasing a main seal adapter and using a 2-piece crank from the get-go. Are there any serious disadvantages to doing this? I'll be running an automatic transmission, so will I just need a flexplate for a 2-piece crank?

Thanks,
Bryan

 

The price is about the only disadvantage. What are you planning on doing with an aftermarket block that a stock block won't do for you?

 

A stock block will work fine for my application, but if I go for a big turbo down the road I'd prefer the peace of mind an aftermarket block would give. Determining what a stock block can handle with good internals seems to be, at best, a wild guess. I've heard estimates ranging from 600hp on up to 950hp. I'd rather not try and find out how far mine would go before the caps started walking and the cylinders started cracking. Granted, that's a lot of power, but well within the realm of forced induction.

 

Oh my... and what is this crank going to be made out of? Unobtanium? Think a bit about what you posted and what context you are speaking of. If you think you are going to be transfering that crank in a forced induction ~1,000 hp application that requires an aftermerket block you either are spending WAY too much on the crank for the current app. or are huffin' the crack far too much.

In either case, think it through a bit, talk it over with someone who has built a motor or three before and then come back and read your post again in context. Build the motor you are going to now, and when you want to build the next one, build that. No two-fers in this.

 

No, I don't intend on hitting the 1000hp mark any time in this millenium. But with the rest of the driveline addressed, I honestly don't think that half of that is out of the question. Much more than that and I think I'd be concerned about the longevity of a stock block. I originally intended on going with a cast steel crank such as a scat 9000, however my machinist claimed that they were somewhat soft, and that journal wear tended to be an issue amongst the ones that came into his shop.

Although a crank is just a small part of the picture cost-wise, if I went 4340, I wouldn't mind spending $150 now for a main seal adapter so I wouldn't have to buy one again down the road. I just don't know of anyone who has used an adapter before, and if there would be any issues with doing such a thing.

If I'm not making any sense, please excuse me. I'd rather ask questions and be called crazy now than to build the engine wrong and be called crazy afterwards.

Thanks for your help,
Bryan

 

I bought a seal adapter from CAT for about $25.
Still haven't used it.

Someone told me that he heard of a rear seal adapter failing in a racing application. If one of those things started backing out while in use, the oil press would instantly drop. But I have a feeling that an adapter would stay put if you were careful installing it and kept your RPMs below the point where wierd harmonics start taking place.

I'm not sure about any of the details on why the part failed. The bolts that hold the 1pc seal retainer in place could back out just as easily as they could with the 2pc adapter.

Those higher priced adapters cost as much as a cast crank, almost. I couldn't see getting a Milodon one for that reason. I talked to a guy at SDPC once about the GM part, and that guy seemed reasonably confident in the service record of the part.