[Rocky 389]

Back in the 70s I was running a '59, 389 in my 57 Chieftain, 2 door sedan and I pulled a rocker stud. I ended up with a kit that included a dedicated drill bit and an oversize stud. I used it and set the new stud with enclosed stud setter goop. Worked ok but I was always worried it would come loose again.
My latest build is a 57 block bored .125" to 370 cu in. I used 73-74 GTO [350] heads because they were like 96CCs, a good way to loose some compression from using old Jahns pop-up pistons. They also have hard valve seats, 7/16ths screw-in-studs [big block chevy pieces] and factory push rod guide plates. Had to grind a little from the bottoms of the valve retainers to clear the PC intake seals with a .90 valve lift Lunati cam. It all works great. I tapped and blocked the oil passage in the block deck...just a little insurance. I went with the reverse cooling block and front cover, made a pair of adapters under the '57 coolant elbows to direct coolant into the late heads. Mine uses a 59 manual bell housing, flywheel etc etc with a 11.75" clutch and a muncie M-21 4 speed. If your car only weighs 1800 lbs I wouldn't hesitate to use a saginaw 4 speed.
My stock '74 rockers oil just fine from the pushrods. I honestly don't remember what pushrods I used but I turned the engine by hand and watched the valves cycle....no weird angles or anything. I have about 10,000 miles on so far. I love it! Runs cool and strong.
Oh, and if you do score a 58-60 bell housing, be sure to get the manual trans starter too. It's shallower than the automatic starter. Mine is in my trusty old 34 ford coupe.