The factory computer is way more flexible than some people who never messed with it (and some who have) would lead you to believe. I ran a 410 stroker, heavily ported heads flowed 60 CFM more than stock magnums on the same bench, 11.5ish compression, 231@.050 .575 lift cam 110 LSA, M1 single plane ported to match heads, plenum opened to look like a real squarebore, long tube ceramic coated headers, 460 ferd injectors, full dual 3" exhaust with crossover, 4.56 gears... ran awesome with the stock tune, fuel trim numbers were close enough it didn't even set CEL, it shifted too early and gained quite a bit with an SCT tuner but it was actually fine with the stock computer, still had brutal TQ with the stock tune.