327 main bearing caps

[Kenneth F.]

I have a 327 block that did not have the main caps when I bought it. I since found out that caps off other blocks did not necessarily have the same center line when originally machined, and might not have enough material to line bore on another block. Does someone manufacture bearing caps that have enough metal to solve this problem?

Ken

[Edward J.]

Re: 327 main bearing caps

Ken, Is the machinist telling you that you that there is not enough left on the caps to line bore the block?

[Kenneth F.]

Re: 327 main bearing caps

Edward, I did not take this block to the shop, after hearing another NCRS member say a machinist would not line bore his block with mismatched, caps that did not align. I do not know how much of an alignment problem there was on the block I was told about. The bores between my caps and block are staggered about .025. The donor 870 block is about 6 months earlier than the 870 block I am trying to save.

Ken

[Scott M.]

Re: 327 main bearing caps

I don't see how there is a problem, they shave the caps and then line hone to the block. The caps would have to be pretty screwed up and very thin for them not to work. Only one company makes small journal aftermarket billet caps, Pro-Gram Engineering and they cost a bundle.

[Larry B.]

Re: 327 main bearing caps

Ken The date of the blockhas nothing to do with the cap alignment.The caps can be cut down so they can be line bored but .025 shift is hard to deal with as you can't put material on the overlap side .You just need to try more caps until you find a set that fits closer.I have a bunch of caps and run a CNC machine that will line bore which is more accurate than line hone.Line hones will not touch the Pro Gram caps.The other thing you need to consider with doner is the rear seal and the thrust.If I can be of any help let me know.

[Jack H.]

Re: 327 main bearing caps

I agree with Scott that there should not be a problem unless something is seriously wrong. When caps are mismatched you absolutely DO need to have the block align bored/honed, but I've seen/heard of this being done successfully many times.

In addition to Pro-Gram Engineering, I'm pretty sure that Milodon still makes aftermarket billet caps that add 2 splayed bolts per cap, i.e. transforming an old small journal 327 into a 4-bolt main block. I looked into this on a drag car engine I built years ago, but ended up going with a newer 350 4-bolt main block instead. Last time I checked, places like Jeg's and Summit had these kits for a couple hundred bucks. Kit included drill guide, etc. so theoretically only an align bore/hone would be needed to be done by machine shop, although I'd probably have them handle the extra hole work too.

I'm sure there are some OEM main caps out there too from cracked blocks that have since been scrapped...may even have a set myself come to think about it.

[Kenneth F.]

Re: 327 main bearing caps

Edward, Scott, Larry, and Jack, I appreciate your sharing this great information about the main bearings on my block. I will look into these options, and probably first try to find someone with the same alignment situation, exchanging bearing caps.

Thank you,

Ken