Stock teener pistons TDC at .080" to .100" below the deck. Thats a serious loss in compression. This is compounded with heads designed for a bigger bore engine along with the associated valves for a bigger engine. To make a teener run, you need pistons that change direction at the deck, or a couple thousandths below the deck not 80 to 100 thousandths below. The valves , ports, and runners need to be sized for the bore it's got. The whole throw bigger at it does not apply. Putting 340/360 top end on a stockerish 318 bottom end, actually hurts it, not helps it. It slows down port velocity. Bigger valve J heads on a low compression 318 makes it perform worse than if the stockers were left on it. Most engines (street engines) live at off idle to 5,000 rpm max. Rev it higher?? Ok how much higher to get the power back? Will that require better rods, better crank? Etc?
