Purchased Used AED 750 HP-HO - Throttle Shaft Damage

Easy fix ... I'm curious to know what engine this will be going on ? I built one of these for my 340 and cannot get the part throttle lean stumble out of it ... 70/76 jets, 8.5 power valve, 28/35 squirters, orange pump cam......

I'm building a strong 383. It will be a while before I get it running. I'm building it from a bare block, so having to search for everything.