Anyone that uses alum main caps in a RB, can you you tell me who to purchace them from and how involved is it to install them. Is this something that a good machine shop can do?
Thanks,
Brian

I bought a set of the 440 Source aluminum main caps and ARP main studs from them, my local automotive and industrail machine shop(Southward in Eugene OR) did the fitting and align hone on the 440 block my customer provided, they made the comment that they went on fine and machined well. They where inmpressed enough to ask where I got them from I'm assuming that they will buy them direct for future builds they do from now on

I bought the BCR aluminum caps along with the Girdle and main studs. As stated above the engine will have to be aligned honed to fit the caps. Any engine machine shop with the equipment can do the work. With the girdle the block pan rail has to be machined flat along with the caps .

What about fitting the new caps to the block registers? Any machine work required for that or do they fit out of the box? I realize that it has to be align honed after installation.
Any options other than BRC and 440 source?

Thanks,
Brian

I think Best Machine offers caps too

Best Machine no longer sells the main caps for rb 440. He laughed about not knowing how to turn the advertisment off on the Moparts webpage as I spoke with them on Wednesday. Ordered Mancini caps so I'll see how things go for the new motor going together.

we make the bcr caps and girdle kits and ours don't need any register modification and should tap down in with a slight interference fit, just like factory caps.

Bought some from Mancinni a few years ago, nice quality stuff. You still want to have it line bored to make sure everything is perfect.

Most all of the caps I've seen, come for the b-engine, and then require extra machining to get to the RB size main.

And don't forget about the thrust. That surface will need to be addressed as well. I have used both 440 and BCR caps. Make sure you get 12-pt nuts for the studs. Hex stuff is really tight.

I was told they need to be align bored, not align honed, during installation. Align boring keeps the radius consistent, but align honing can change the radius from the crank centerline due to the differences how the hone removes material from the harder iron (block) side and the softer cap (alum) side.

FWIW, I like the BCRs, and didn't know Best stopped making theirs. I know one person who broke a Best cap, but don't know all the details to indicate where the issue was.

yes the caps need to be align bored and yes they come in the 383/400 journal size. its not a problem to remove extra material. on most engine the #4 cap has the most stress due to its position in the firing order. that cap cracks. we use 6061 aluminum that's made in the USA for our caps. these are plenty strong and more ductile than a 7075 aluminum counterpart. feel free to call with any questions we're always available to get you some answers. sometimes out in the shop and don't hear the phone ring. so leave a message.