I’m replacing the side cover gasket on my 1934 Master engine that was replaced by the previous owner. Currently it is held on with 1\4 20 hex head bolts (all matching with a L head mark) but there is also a set of slotted stove bolts that came with the car. Which is correct? Thanks in advance. Mike

The 1/4-20 round-head screws.

The slotted stove bolts ae the correct fasteners. The same for the oil pan That is why they are called "Stovebolt Sixes".

Thanks, I was questioning it because L head mark hex head bolts are used in certain applications on later Chevrolets. I think the Corvette suppliers actually sell them as reproductions. I thought it odd that they all matched on the 34 side cover. How they ended up there I’ll never know. Thanks again. Mike