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?

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Let’s keep it cheap to start with and then add on all the bling later. To be honest, I’d rather start this money spending on best bang for the buck with the ability to add other options later. So, it would be IMO that money well spent now instead of later for the best results for now and later would be in the drive train area.

The A-500 series OD would be costly though a huge bennifit overall later. Coupled with the 3.55’s, this would equal a 2.45 final drive feel ratio. Finding a non lock up converter can be a pain but at least at that point, converters are cheaper than lock up converters.

Engine wise, a decent mileage cam with some power would be in the 210 - 216 intake duration @.050 range. Add a LD4B or Performer or on the very cheap a OE iron 4bbl. intake, 600 Holley/AFB and headers w/a 2-1/2 exhaust.
Keep the stock heads stock for now.
Use a good ignition system and IMO, you’ll be in good shape with a mid 13 second car that gets good mileage when at cruise.