more slant6 hp!
Sorry if I'm butting in as I've not seen any other threads about what you've done to the car. Not wanting to squash your hopes of hp with bolt ons, but I would advise maximising what you have so far. Make sure the valves are set right, timing and advance right, carb right, tune up right with quality parts etc. Once you have done that then I'd consider going from there with bolt ons. Just my opinion and you know what they say about them!!!!
Congrats on your car and the slant. I was going to go V8 in ours, but looks like the slant is there to stay for a while.
Cheers