Hello everyone,
I’m putting together an evolution engine from a lot of mismatched parts and I would like to see if an experienced evolution builder could share some information, I have a case with the common male/male cylinder studs, and I picked up a set of early heads (1985) set up for the male/female cylinder studs, I didn’t realize the difference until I had the valve job done that the holes in the head were smaller ID for the early studs. I’m wondering if I retrofit to the early studs that fit the heads? I’ve been told that the studs can be prone to pulling threads, so I don’t want to disturb them if I don’t have to, and I’m assuming the current ones are a better design than the early ones. Can I bore the early heads bolt holes to accommodate the current studs, is the depth to the top of the heads the same? I’m not having much luck finding evolution specialists, I really appreciate any advice I could get.

You could bore them but I wouldn’t bother. Those early heads were junk. Find some later heads & you’ll be better off.
I own an 85 FLHTC. The original heads are door stops. Work good there.

1992 were the head breathers, so I’m OK there.

so you are saying the older stud/bolt set up is the same length as the newer one? I won’t have the newer head bolts bottom out on the studs or not be long enough to catch the threads?

What studs do you have on your 85? The older ones?
If someone has replaced the studs and bolts on an 85, and just drilled the holes bigger, I would have the answer before I stick more money in it.

Most people have been telling me not to bother with any Harley engine, boat anchors, every single one, but that’s not sharing any knowledge, so I’m sick of hearing that.