TKO 500 in a classic

I don't think you can lower the engine enough to get it right. I put a tko 600 in my 67 GT with FE. I really did not want to cut the tunnel and tried not to but I could only get the angle to 6 degrees with the darkhorse cross member, any closer and it would hit. The correct angle should be about 3. If you need to see a difference just cut a 2x4 to the length of the engine and tranny and set it at 6 degrees. I thought it really looked stupid setting in there like that.
My hooker headers hit the steering box and idler arm. They also set about 2 inches lower at the collector. I don't think I could have ever got the correct pinion angle to prevent wheel hop. So I made the decision to cut the tunnel and fab my own cross member.

I can send you some photos if you like. John

Yeh an FE would be tough, however I was just thinking with a 302W or even 351W. You probably would need custom headers though.

With a 65-70, you do need to modify the tunnel to fit a tremec at the original 3 degrees spec. The 69/70 do have more room than earlier ones, but I still had to cut mine.

Many folks have not cut their tunnels, and use the commercially available cross-members to hang the engine/trans low enough that it doesn't hit. I guess it wouldn't hurt to try to install the engine/trans and observe the angle. These cars do vary from one to the next. My darkhorse cross member wasn't even close, holding the drivetrain at about 7 degrees IIRC. I made my own crossmember to get back to 3, which required the sawzall.