Flywheel bolts I have bought are all shallow height heads. My last problem was finding right length and then no one has lock strips now. I was told to use inner star washers on them and Locktite Red. I did that, and still holding after two years. Expect to pay about $2 or more for each bolt! I once did a Jeep 4 cylinder that book said to buy new ones and they wanted $8 a peice at dealer! What's with that? $40 dollars or more for set? They say old ones stretch when torked, and can't reuse. I've re-used them for years on everything else I built. I DiD re-use the Jeep ones and used locktight on them.
I wouldn't use the "Hardware store" type myself, but whatever. On the flywheel...don't 292's have own type as balanced diff and diff bolt pattern than 250's had? Maybe that's whay diff holes size, so you don't mix up? You could drill the smaller holes out on flywheel to match 1/2" holes in crank maybe, I wouldn't bore or redrill the crank if mine. Would have to be apart for that anyway. I would modify flywheel or find right one for your crank. Better check with Inliners site to see if they interchange. Would think they should know. Or, maybe Clifford's shoud be able to help. They do only small engines.
