Well, I'm probably way out of my league here, but here's my 2 cents. I'm not the high tech guy that some of you are and that's fine. I am old school hot rodder. That means you install it, drive it, and if it's not your cup of tea (or Beer)you Changeit.I have always believed that a Hotrod should first be a safe vehicle, look great, sound fantastic, then be accomadating to all of your needs. Just through doing alot of different things in my past 36 years of driving, here's what I found out to work pretty well.
Any Inline six is going to give you enough torque to pull a hole shot on most new cars. Even my stock 216 & tranny with a 3:90 rear was decent. My new car, which is a Master 85 Business Coupe was 2849 lbs in stock form. By removing the stock rear, torque tube, tranny, motor,front seat, and front end, I got rid of approx. 1,300 lbs of bulk(I actaully weighed these components, just curious). I replaced those components with a 1970 292,T-5, alum drive shaft, stock 10 bolt nova rear, Dakota buckets, Mustang ll IFS. I added back approx. 750lbs more in components. That's a true savings of 550lbs!
Guy's, you don't need computers to know that loss of weight and increase of horsepower and torque = huge gains!
Now I have a 1984 Camero Z-28 T-5 with a low first gear and fairly low 2nd. Third you can wind out a bit and forth is 1:1. 5th is 0:76 so I get very nice off the line grunt and a cruising speed of 70 MPH at 2200 rpm's! I've never checked the milage but I didn't do all of this stuff for good gas milage. You want good gas milage, buy a horse!