sbf valve guides

Machineshops used to knurl the guides when slightly worn. I'm sure some still offer this. The knurling doesn't last as long as new guides, but was a cheaper alternative, especially if you're just building a weekend warrior and not a daily driver. My 1964-70 Motor Repair Manual gives valve guide clearances of .001" for the intakes and .002 to .0027 for the exhaust. It doesn't specify whether that's open or closed. more likely it's closed I'd think. Small block stem diameter is listed as .3416 to .3423 (intake) & .3406-.3413 (exhaust) I'm assuming the gaskets you're talking about are the umbrella seals, these work to a certain extent, better than nothing but less than PC type seals. The umbrellas get old and brittle at some point and find their way into the crankcase and oil pump eventually.

The motor book just list those specs, I'd assume that anthing smaller in diameter needs to be replaced. As for those bronze guides, new guides are usually longer than needed so they'll fit a wider variety of applications. Once they're installed the machinist can trim the tops. As for loose guides and oil consumption, that's the least that can happen. I'd be more worried about dropping a valve head with the sloppy guides.

I don't know what heads you have but aside from the stem lengths, all the SBF 1.78/1.45 valves are interchageable as to fuel types. The Pre April 66 heads had shorter valve stems than the post april 66 heads. Then the next change was I think made in late 77 when the switch to pedestal rockers was made. Then the E6SE heads had even shorter valve stems than the E7TE's.