RAMM said

The problem with the Pro-Comp/Speedmaster stuff--(at least in the SBC/SBF heads) that I've personally seen more than once--Is the guides seem to be made out of wax. Ok a hard wax. The guides are shot in a few hundred km's . The worst part is the OD of the guide is not a common or nominal size like .502" I think they are some dumb proprietary size like .544"-.545" like Brodix. So if they are shot you have to order some GOOD guides from Brodix at about $25-$30 a guide. Have they changed the guide material since? I do not know--maybe? Hopefully. J.Rob

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PRH said

The guides absolutely used to be junk.

The oddball OD sizing is like .506-.507.

I repaired a set of BBM heads that came off a mud truck....... maybe 50 miles worth of use?
Roller cam combo........ some of the intake guides had .009” clearance....... but all 16 were too loose to leave as they were.

Several years ago I had some Patriot SBC heads in the shop that had a few wasted guides.
That was the first time I encountered the oddball .506 OD thing.

I ended up reinstalling the used guide with some loctite...... and put a liner in it, and the few others that were quite big.
They were pretty soft, and didn’t ream for the liner that easily.

The .545 Brodix size isn’t really that uncommon.
Edelbrock uses that size in certain heads(BBM RPM for one).

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