Fuel injection or aluminum heads

73duster513 said

I have a 1972 stock 318 other than eddy 4 barrel and intake with stock manifolds
Does not smoke at all
727 transmission
8 1/4 suregrip rearend 3.23 gear
I would like more power and reliability I drive on the street and highway mostly I want to be able to jump on the highway and run 70 mph for 2 to 3 hours without having the rpm tapped out for that long hence why I have 3.23 gear
Parts I already have to put on it
Purple cam 410/425. 211/218 @ .50
110 c-line
Msd 6la with distributor and blaster coil
And a set of long tube headers (unknown manufacturer)
I have roughly $2500 to spend as for now

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What do you think efi would accomplish? Compared to a well tuned carb, you won't save enough gas to pay for the efi. I went from 10-12mpg to 12-13mpg on average.

Aluminum heads could help or hurt your combo. A 72 vintage 318 likely doesn't gave enough compression to make the juice worth the squeeze.

If you HAD to choose one, I'd suggest the efi since I don't think heads will gain you anything unless the future plan is to upgrade significantly. But a significantly racey 318 would absolutely suck for 3 hrs at a time on the highway. Build a truck motor, which can still benefit from a larger head, and you'd be better off. But those heads aren't going to improve all that much in your typical highway rpm range and rebuilding the engine into a stump puller seems like a lot of work compared to what you're asking.

I think as recommended above, a better converter would probably yield more smiles per mile and not tank your mpgs either.