Help me get into the 12's for cheap
I totally agree with "doogie" that horsepower isn't everything.....But with that said, being a street/driver type car, you'll need some extra power to make up for some of the deficiencies versus a race type setup. I'm guessing your 73' in full street trim will weigh close to 3500lbs with you in it. With a perfect race combo & gearing, 320/330hp could get you in the 12's pretty easy. If it was me looking to do what you want, I'd shoot for 350/360hp to cover for the car being in street trim and having 3.55's.
I'd forget the teen at this point.....yes it can do it, but the extra cubes & 3.58" stroke, just make it so much easier. I agree the LA360 may be your best option form a cost standpoint. With a appropriate regrind, cleaned up heads, a Eddy RPM intake, a 750ish carb, along with a stout matching converter, as "doogie" said, and some sticky tires, I think you can get there.
Depending on the outcome from that, a little chassis tuning could be helpful? That really depends on how far towards racing you decide to go.
Good Luck! it's gonna be a lot of fun. :thumleft: