318 REBUILD IN 67 BARRACUDA
I have considered aluminum heads and I could paint them so they look more original but my head guy said it wasn't going to be that expensive to put in larger valves
You don't need big valves in a 318 streeter, for one thing.
And to make best use of premium fuel, you will need a final cranking cylinder pressure of around 160 psi, but to stay out of detonation with iron heads, no more than ~165psi.
The thing with alloy heads is, that you can run the pressure up to, in the range of 185 to 200psi. I run 180psi on 87E10.
Pressure is power, specifically at low-rpm. Which is what a longer-period cam always gives up.
Plus, when the bug for more power bites, the alloys will bolt right on to the biggest of small blocks; and you won't be stuck with the useless open chamber big-valve heads that you spent good money on.
IMO, with a 318streeter, you can sacrifice whatever you want to, so long as it ain't pressure.
Without the pressure, and WITH a bigger than stock cam; you will need a higher than stock stall and quite a bit more than 2.76 gears. I'll guess a 2800 and 3.23s at a minimum, up to 3.91s preferred..
The point is this; that altho the buy-in for the bigger cam is relatively small, the loss of pressure will end up costing more money.
But the even-bigger picture is that NONE of this makes any sense at all, breathing thru 273 logs and a single exhaust. If your engine has to pump it's own exhaust out, that costs power. And gas money
BTW-1
The Second generation Barracuda is the heaviest of the A-bodies of it's era. And that, on a 108" wheelbase, go figure. The folding rear seat is a tank, and the buckets/console is more fat. The heavy back glass is at least in the right spot.
To it's advantage are the very roomy rear wheel-wells. With a little work I installed 325/50-15s into mine; on alloy wheels of course cuz they weigh about half of the same-sized steel wheels.
Happy Hot-Rodding
