ARP # 662-1007 bolts
M10 X1.5 Unfortunately, these are sold in blister packs of five! You need six. I also bought some 3/8" washers too, but can't find the part #.
Any grade 8 3/8" washer will work fine. I have a bunch of .120" thick 3/8" washers should you have difficulty finding some. I also have a spare 662-1007 bolt or two since I had to buy two packs. PM me if you want to purchase these from me.
I couldn't find the right length studs, so bolts were used. Maybe you'll have better luck than me finding studs.
The last engine I assembled I found the 4 bolt mains tightened up a bit too much when final torquing the outer bolts to the block. Everything was registered correctly but a little too tight for me. Took block/crank back in to machinist and everything was found to be in spec. The journals just had to be opened up by honing to the high side of spec. Just giving you a little heads up for your machinist when the time comes for machining.
This was the first time this happened on the three blocks I've added 4 bolt main to.