What size engine for the online/Youtube EC?

I think a stroked 318 with a 360 crank would be interesting. This would give all those 318 owners an idea of what could be done keeping thier original engine. I am a 340 person and have 3 of them. One original to my 68 FS FB which is under restoration now. Hope to get about 380 HP with a 280/480 Mopar Perf cam and Eddy heads, TTI headers. Dyno'e close to 400 HP with a set of mildly ported X heads, Air Gap, 750 CFM AVS, and 10.25:1 pistons at +0.020 (I never bore a block more than needed!). That was at 5800 feet and altitude corrected to STP.
Unless you're able to go to 4.00" You will have a hard time with the NO custom piston rule. I'm trying to keep this affordable. J.Rob