Did I do ok on this?

My 68 Formula S weighs in at 3450 me not in it. That's a lil porky for a 340 never mind a 318. You can make any combo work, just by using the right combo of stall and gears. But with smaller engines, you may not be happy with the sacrifices you have to make.
If you start with a bigger engine, there are fewer sacrifices that you HAVE to make, and they become options.
For example; a 360LA falls together at about 10.7 Scr with 63cc chambers. Very little machining required.
BTW,
my combo already sports a few lightweight pieces; Like alloy; heads/intake/4-speed trans case/wheels, a mini-starter, no spare, and no rear seat.
The heavy stuff is; the exhaust system; TTIs and dual full-length 3" pipes with 3in/3out dynomax muffs, a GVod, power-steering, PDB, and a real battery.
The bonus is, the weight distribution is down to about 52% front heavy.