I had a pair I stored for 15 yrs, off a running truck.... took them in, cracks off the I take seat toward the chamber/plug more in between valves. Never leaked coolant.. but it's a time bomb. And the seats can burn out with a crack across them. I stored garbage for 15 yrs. Lol. Every set since has been cracked, I can see it in the yard, dont even need to pay for them. Last one I sent through the windshield of the van I was so irritated . 714 might be a better casting
Chambers are overrated till you get to mountain tops of power making, then they can be a holy grail...but that's miles beyond what 302 head guys are doing. ..and that's the WORNG chamber shape.