BBC lifter bores

I have a Donovan D500 BBC aluminum block that I want to bore the lifter bores for the .904" lifters.
I talked to Donovan but they are too busy with building their new blocks that they don't do and repairs or modifications anymore. They said just to ream the current .842 bore to .904" and don't use bushings but my local guy said he won't do them unless he installs the bushings with his BHJ correcting setup. They worked fine with no bushings before. What's your ideas? Also their is a shop making just a reamer to go from the .842" to .904" that I thought might be good due to the fact that this block probably doesn't need to have them done on a correction style fixture like the BHJ because it was probably done on a CNC when built by Donovan.

 

You could have a tool grinding shop cut the end of the reamer down to the .842 to act like a pilot, if your doing it by hand.

But, it would be much better to either get it up in a mill or use the BHJ fixture to make sure you have the hole straight and round , not all wobbled out ! IMO

 

There is no reason to put bushings in, in fact a lot of times the bushing just weakens the lifter area of the block due to the extra material removed. I usually only install bushings for repairs or key way lifters. You do want to have somebody do it that has a cnc or a fixture. In a alum block you generally want to have about .0015 clearance, would be really hard to hold the tolerance with a reamer.

 

Mac - We CNC bore the STD BBC lifter bores to the .904 size without using lifter bore sleeves. If you are interested please call or e-mail me
519-451-3890 / rob@atchisonracing.com

Atchison Machine Service
located in London, Ontario

 

Sounds good Rob I will do that. Thank you