I'm currently working on a 71 Chevelle I've had for years. About 20 years ago, I built a 396 (402) with 4-bolt mains, hydraulic tappet cam, forged pistons, iron heads (094's, I think), Comp roller rockers, Holley strip dominator intake with a 750 on top; around 425 horses.
Transmission was a turbo 400, manually shifted, reverse pattern; rear was a 12-bolt 4.56 posi.
I'm going from the ground up again, and am considering this a mild pro-touring effort. I want to keep the "GM-ness" about the car. Keeping the factory frame, and it's currently getting all factory welds ground and re-welded (never seen such bad welds on a frame!), and will add the Hellwig kit to box in the center rails. Using the ABC pieces to box in the rear frame. Planning on Global west suspension front a back with coil-overs. I do NOT want to lower the car much below stock height, if at all.
Transmission will be a 4L80E, and rear will be a Moser 12-bolt, probably with 3.55 gears.
I need opinions on engine selection. This build demands a BBC in my eyes. I originally was going to re-gasket the 396, as it has less than 500 miles on it. I had also put a Holley dual sync distributor and Terminator throttle body on it just prior to project start. However, I've been pondering going the route of Chevrolet Performance parts engines, and have been looking at the 427/480 L88 or the ZZ502/502.
I would really like to do the 427 based on my experience with them in the past. I like the internal balancing. I would use the dual sync distributor and Terminator on top instead of the supplied HEI and carb. However, it's $11.5K - that's a HUGE cost! The 502 is about $8600, no intake, carb, or distributor. Still a lot of money, but seems more sensible.
I'm open to reworking the 396 as well, perhaps some aluminum heads and a hydraulic roller cam for sure. I'm interested in hearing opinions.