360 Advice Needed - Autocross / Street Engine Build
A bit of a different type sleeper build...
I respect that. That's totally cool.
If you're willing to make a custom heat shield then think real seriously about custom headers - even with shorties. This way you can make them real performance pieces and fit your car specificly. In terms of performance, this means good match to the ports at the tops, the right size primary and then possibly a step up, and a nicely merged collector if there is room. By that I mean that the tubes taper together at a nice angle, not the high dollar fancy merges. If the primaries are pinched together in the center as Headers By Ed recommends, a bonus is little less space taken up.
The Magnum Muscle cam looked more promising to than the others. See what you come up with compression and octane after you've confirmed the head cc's. Maybe a different cam will work better with the limited octane fuel.
As far as your autocross goals, you can compete at least some modern stuff with just the basics - some oil control in the pan, springs, front sway bar , decent shocks, and of course a sticky tire. As you probably know, even within SCCA, competion within a class will vary from region to region.
Street Prepared: Softest PAX, but if there are competitors with National level cars (and skills) in the region, its another ball of wax. Besides, the aluminum heads don't count as 'bolt on' modification, so nix that.
Street Mod: You can easily fit in. This was a fun class around here for a while. Then it got really tough to keep up with - in fact I couldn't, although always finished decent. Regionally now its not as competitive or as populated. I still run here when I show up and always do moderately well.
C Prepared: You could fit in here too. Some of us call cars like ours CP lite 'cause they're no where nearly as developed as Sandburg's 'cuda never mind Meier's and Stagnaro's cars. Again depends on local interest. Philly region rarely has any CP cars. In NNJ, before the advent of SM, we had a great group CP (lites).
CAM: Check this out for a possibility. The rules are evolving, as are the cars.
There also may be various vintage and 'street tire' classes offered. Since you're going to bigger diameter wheels, you could run those 200 TW tires. I took a look and was not impressed with the low temperature limitations and high cost (compared to R-comps).
But do have something in mind so you can have some fun competition.
