4-bolt main bearing caps '66 942 block

[Steven S.]

Could someone confirm for me that the "334" caps are the correct number that would have been installed on the '66 4-bolt 427 blocks?

Thanks!
Steve

[Joe L.]

Re: 4-bolt main bearing caps '66 942 block

Could someone confirm for me that the "334" caps are the correct number that would have been installed on the '66 4-bolt 427 blocks?

Thanks!
Steve

Steve-----


No, I don't think the "334" caps are original to any 1966 big block. However, they are certainly usable for any 66 427. The "334" is a derivative of the part number for these caps which is GM #14015334. They are a heavy duty, nodular iron, SERVICE-only cap released about 1979 and they're still available from GM for about 26 bucks each, GM list.

As purchased from GM, these caps are "unfinished" with extra material so that they can be fitted to any block, but this must be done by a competent machine shop.

A photos is shown below:

[Steven S.]

Re: 4-bolt main bearing caps '66 942 block

Hmmm, well I'm certainly glad I asked, for some reason I thought those were the correct caps.

Does anyone know what if any markings would be on original '66 BB 4-bolt caps?

Thanks Joe, you are the best!

Steve

[Joe L.]

Re: 4-bolt main bearing caps '66 942 block

Hmmm, well I'm certainly glad I asked, for some reason I thought those were the correct caps.

Does anyone know what if any markings would be on original '66 BB 4-bolt caps?

Thanks Joe, you are the best!

Steve

Steve-----


I wouldn't be too concerned about this. While they're not original to a 1966 block, they are equal to or better than those originally installed. No one is ever going to see them after the engine is in the car. Even if they could see them, about 99% of the folks wouldn't even know they're not original.

A bigger factor here is that if you found these on a block, it might be an indication that the block was not originally a 4 bolt block. Functionally speaking, even that's not a problem since a converted 2 to 4 bolt block is just as good as a block that was originally 4 bolt. However, there might be some other aspects of "originality" regarding such a block that might be a problem.

If one is going to convert a 2 bolt to a 4 bolt block with stock-type caps, then these 14015334 caps are THE ones to use. Since they are "unfinished", one is guaranteed they can be machined and fitted to the block. With a USED set of 4 bolt caps taken from another engine, there's no guarantee there's enough "meat" in all the areas necessary to fit them to another block. There usually is, but there's no guarantee. Plus, the caps will be NEW.

Unfortunately, there is no Gen IV 4 bolt REAR main cap available from GM.

[Steven S.]

Re: 4-bolt main bearing caps '66 942 block

Thanks Joe, I am currently evaluating a 942 block that has the 334 caps, that was my reason for asking. So far signs are pointing to this block being a converted 2-bolt.

Thanks,
Steve