Horsepower with mileage options

Penstarpurist said
Okay guys, here is what I'm wondering. My son and I are bench building options for his bone stock 1971 Plymouth valiant. Current set up is 318 2bbl 904 stock. He loves the car, but has been wanting to give it some pep but wants to retain drivablility and gain some gas mileage. So he is thinking aluminum heads, aluminum 2bbl intake manifold (yes, I said 2bbl aluminum) he says they exist. Dual exhaust and mild cam. Gear change out back. I think that the way to go would be keep the iron heads, stock 340 cam, 4bbl intake either stock steel or aluminum, and carb to match, dual exhaust and a set if 355's out back. Put all the stock parts on the shelf to put back stock if ever wanted. What do you guys think?

Whatever you do; do not put 74 plus cc heads on that 318 with a 340 cam, and 3.23 gears or less, with the stock TC. I did that once back in about 1980,and it was a total waste of time. The Dcr was so low that, (I didn't know about Dcr/VP back then), that 73 Swinger felt like it weighed 5000 pounds. But it had pretty good passing power at 75mph.......... in second gear!Eventually I put a 2800TC on it and it was still doggy down low. Finally I put 3.91s in the back, and that sorta woke her up. But gas mileage? Fugedabowdit!
I still have that engine, now returned to stock, but with a TQ on top. That was my winter engine for 5 in a row. It goes really good with 4.30s and double overdrive, and studded tires.