351C Rebuild suggestions
For a while my '73 Mach 1 would lose oil pressure after about 30 minutes of driving. It had 5 p.s.i. at idle in gear at one point. Last night, I pulled it around front and it had 60 p.s.i. I got down to 20 after about 15 minutes of running. This morning, I started it up to drive it to work and the gauge was reading 5 p.s.i. It then, dropped to 0 if I revved it up. The engine in the car, as far as I know, is original. It is a 2v Cleveland with an edelbrock intake and Holley 4 barrel carb.
I picked up a 4v Cleveland engine a few months that back that I was planning on building for my '70 Mustang. The engine is rough and I only have the heads, intake, and crank. I don't think the crank is any good. I'm wondering if I should rebuild the engine that is in the '73 and be done with it, or rebuild the '73 block and put the 4v heads on it, or just build the 4v block and swap the engines out. This also leaves me with what I should do with the '70. I have no problem keeping the 302 in the '70 but it vibrates badly and needs a rebuild as well. I could put the 2v Cleveland in the '70 if I build the 4v for the '73. The '70 also has a T-5 and I don't think it would live behind the Cleveland.
All this being said, once I start building the 4v, what would be the best all around performance build? If goes in the '73, I want it to be comfortable to drive yet be fun at the track. The car has a C6 and 2.75 open. If it goes in the '70 it doesn't have to be as tame, but I would still like it to be streetable. This car has T-5 from an '04 mustang V6 and 3.50 equa-lock.
Sorry for this long winded loaded question and thanks in advance for the advice!
1970 Mustang Coupe, 302, T-5
1973 Mustang Mach 1, 351C 4V, C6
1998 Mustang GT, 4.6, T-45
2001 F-250 lariat, 7.3
2015 Escape 1.6 ecoboost
2019 Mustang GT, 5.0, MT82