It is my belief, for these cars anyway, that the only important measure of performance is pounds per horsepower. This measurement gives you direct real world comparisons to other vehicles and does not get you trapped in the "I need 500 horse power" game.
If your replica weighs 2400 pounds and produces 375 horse power then you have a lbs/hp of 6.4
6.4 lbs/hp is the ratio of the new Z06 vette (500 h.p.) which weighs in at 3170 lbs.
I have been telling customers who want very fast Cobras that handle well to consider this fact. Trying to control 500 - 600 horse power in a very light car is tedious. You will also have a more usable ride, which gets good mileage, with less mechanical trouble at lower horse power. Just my .02
--Mike / Turn Ten Racing, Inc.