I have a 69 Charger with 426, TKO600 and 4.10's which I got on the road earlier this year. I bought it as an incomplete project and didn't get any real information on the engine, other than it made 520hp on an engine dyno (with headers). I think it's a "crate" engine that's been freshened up (I was told it was as it was burning oil initially) and a larger hyd flat tappet cam. Very choppy idle, 8in vacuum at idle with 23deg initial at 950rpm. Has exhaust manifolds, dual AVS2's on an edelbrock single plane intake. 150psi cranking compression. Made 405rwhp on a Dynojet and noses over/breaks up just over 6k rpm so I'm assuming it's light on valve spring. My thoughts are this- Remove engine, rebuild with a bit more stroke (4.0-4.25?) and 7.1 rods. 11 to 11.5-1 compression pistons that aren't 800+ grams, port the iron heads and replace the manifolds with headers. Would like it to rev to 7k and make 500 at the wheels. Prefer rpm and horsepower over off idle torque, plus I want to keep the trans in one piece. Undecided on type of cam. I'm reading hydraulic roller is problematic on these, unless something has changed with what is available parts wise. Any thoughts on solid flat tappet or solid roller? Not going for crazy power so not sure if solid roller is worth the extra cash. Or if there is a very high quality hydraulic roller lifter that is known to survive I would go that route. Any suggestions appreciated. Thanks!!!