Mopar used to sell a cut-to-length kit that you could assemble yourself. My 367 has one of those in it. It comes in handy if you need to swap to thinner gaskets, just take 'em apart and trim as required.
But; did you know, on a 3.91x3.31 teener, in a streeter;
60779s will drop your Scr to around 8.85 with stock flat-tops .057 in the hole. Almost any performance cam you run with that will have a soft bottom end. The 340 cam for instance, will drop your cylinder pressure to less than 135psi@800ft elevation, worse as you go up. This is a direct low-rpm torque loss, and will require a hi-stall to overcome. In the meantime, your fuel-economy will tank. Have you taken steps to overcome that?
Those aluminum heads are nice,(I run them on a 367) but for best results, the pressure needs to get up to around 185psi. At the low Dcr of 7:1 that the 340 cam would make, it's gonna take quite a bit of rpm to wake then up, say 4000 with that 340 cam. Which with say 3.23s, will begin to come in around 40mph with an automatic in first gear.The cure for this might be 4.10s, to bring 4000 down to ~31mph; still quite a wait. 'Course if she's spinning, none of this matters...... but spinning is the slow way to anywhere.
Below 3000 to 3300rpm, if not spinning, it's gonna feel like a tired stock 318.
To get to 185 psi with the 340 cam, would require ~11.2 Scr. Which with a stock 318 swept of 652cc comes to a total chamber volume of 64cc, requiring a much smaller head volume. In fact, you can't get to 64cc with flat-top pistons down at .057 (11.2cc), with any heads period. So the first order,IMO, is to get the pistons up to zero-ish, then with the .039 gasket(8.8cc), you would need 55.2cc heads..
To use your 63cc heads you would need 8cc pop-ups on those zero-deck pistons...... The Q is already at gasket thickness of .039, so that's gonna take a funky custom reverse-dome piston to achieve. Or some combination of dome and head-milling.
Do you have to run 185psi?
No,of course not.
But the V/P index at185psi is 138, just enough to have fun with, with say a 2800TC and 3.91s.
Read about VP here; V/P Index Calculation
So if she makes only 170 psi, you might as well have stuck with iron heads at say 160psi. They might make the same power, better low-rpm torque, and; 160psi is way easier and cheaper to achieve.
A better idea IMO,in order to use a 340 cam,, is to start with small-chamber iron heads, and or forgo the Mopar 340 cam all-together. There's lotsa "better" less pressure-hungry performance cams out there; I used probably one of the worst examples I could have, just to drive the point home, and because that's what everybody seems to want to do.
