The bolts for the 340 caps are much longer and will not work on these caps without spacers,
318 bolt on the top,
340 bolt on the bottom.
340 bolt has washers to show the difference. These caps are usable on a 340 just weaker and would be good for a driver but not a High Horse power engine.
You will need to use the 340 bolts with the spacers/washers to fit the windage tray. Or find the very rare 318 windage tray main cap bolts as pictured on the top.
Just some info for the buyer and seller.