The real problem with small block Mopars is the valvetrain. They have kittywhumpass pushrod/rocker arm angles and suffer a lot of valvetrain issues at high RPM.
Pretty much all the small blocks had valve train issues, the mopars in particular. Ford had them too, not as bad. Chevrolet had issues but they also had more things available to fix them. Used to fit something called a jo-mar stud girdle on the Chevies. Totally different units but they made one for small blocks and large blocks.
I put timing gears on top and bottom, no chain. With a little offset bushing which went over the pin aligning the cam gear it was possible to time the cam gear off of the crank gear. By being able to adjust the entire valve timing assembly in one place it was possible to time an engine for low end torque or high end screaming or a moderate setting in between.
In the big block Chevy line up I favored the 427, the NASCAR mystery motor from the early sixties. They released it on the street after a year or two, first shrinking it down to "just" 396CI. Just the way things worked out I spent most of my big block time with 454's. I don't exactly like 454's from a technical standpoint but no question that they can be built to run and hold together.
I planned to build a Ford Pinto with a big block Chevy in it, kind of a superspeedway Modified, modified enough to be street legal. A big big block, maybe 508 or bigger, a rock crusher Muncie, and a superspeedway quick change, Halliburton, Winters, or whatever can hold up to that kind of horsepower.
I also leaned towards a dual engine street rod to top 1000CI when I was younger. Have it set up where I could time the engines to run as one which should have a wicked thump, or 180 degrees off from each other which should make it purr like a luxury vehicle of old. It would be running as a sixteen cylinder where with the two engines firing together it would seem to be a monster V8.
Just a few ideas for a Sunday afternoon grocery getter or something to cruise the park!
Hu