Help on 408 build

PRH said
Well, unless the heads have been milled substantially, it’s not 13:1.
Typical stroker flat top piston, zero deck clearance, .040 gasket.......even with the heads as small as 60cc works out to only 12.14:1.
(13:1 would require a 54.5cc head)
If you added 10cc worth of gasket(19cc total) it would drop to 10.83.
That’s if the heads were as small as 60cc.
If the heads were a more “normal” 65cc, it would drop to 10.28.
69cc, it would drop to 9.89.

Zero deck, 5cc pistons, the .098” Cometic gaskets, 64cc heads...... puts it at 10.08.

Add some cam duration and you’ll be a lot closer to pump gas operation(might need octane boost for WOT operation).

My suggestion is pull a head off and get some measurements before you order any parts.

Your right on that. I quickly just pulled that number from my last stroker build where the piston was .010 above the deck and it had 55cc chamber. But it has 230-240 cranking compression. That’s way above the 180 psi pump gas limit. And for the guy who’s motor pings at 9.5 to 1 something is very wrong. My street 360 has 11.14 to 1 and doesn’t detonate at all even with a 100 shot of nitrous. Mopar small blocks have a very good chamber design that is very tolerant to detonation. Putting better heads on a motor is not a “half *** jerk off” solution. It’s killing two birds with one stone.