aluminium head questions

Gear is a 4.10 w/ 27" tires. I have a 3.55 I can swap in for street driving if the 4.10 gets annoying (and it does above 55 mph). Car weighs 3400. I'd like to get into the mid to high 11's. 550hp would be awesome but I'd be happy w/ anything over 500.

I can spin the tires at 20 mph or so but not much above that.

I've got the vacuum outboard carbs and the only tunning I've done on them (besides idle mixture) is change the vacuum springs to get rid of the bog it had off then line. It runs good but I'm sure there's more there for someone that knows what they're doing. I've contemplated adding the Promax metering plates but wasn't sure if it was worth it or not.

I'm talking to Modern Cylinder Head about CNCing the MP heads. They have a program for the Eddy's and this is the same head.