I went with the Moldex crank in my 525 stroker, but it was originally going to be a 494. The block is the weak point in this engine, but the strength of the large crank compensates for the block. Offset grinding the stock crank to a 2" rod journal weakens the cast crank considerably, and many say the 494 is just not built to last. Mike himself suggested the better 4340 Moldex crank for my engine since there was concern over the strength of the 494 topped with Stage IV heads. You will also need to have a very good flowing set of heads to keep up with the demands of the 494. A set of ported aluminum stage one heads flow well beyond the ported iorn heads, and can take an extra point of compression with pump gas. Ported aluminum stage one heads can flow even with ported aluminum stage II heads on the intake side, but fall a few CFM short of them on the exhaust side. Stage II heads may flow more on the exhaust, but headers are less available for less applications, and cost more. The aluminum stage one heads might be nice on a girdled 494, but I would not bet on the longevity. I also suggest you keep the RPM limit well below 6500.
Personally, I would concentrate on building stout a 462 with a girdle if you are to exceed 550 HP. A street driven, pump gas swilling 462 can be built with close to 600 HP using the aluminum stage one heads, a worked set of stock rods (or billet rods) and forged pistons. It is also a proven combination that holds up. The SPX is coming out shortly. The SPX is the KB Wildcat manifold now being produced by TA. It is slightly better then the SP1. My previous 462 was similar to the combination above with more compression and iron heads. It had a street suspension, 2" headers and 3" exhaust. It was driven to the track (race gas), and ran 11.20 at 120 through the exhaust at 4100 pounds with driver. That was fun in my book! I would have gone with a slightly smaller cam (TA 510 or the solid TA 308), returned to the 3.55 gear (.15 slower in the quarter vs 4.10 gear), a 9“ converter (vs a too loose 10” at 4200 stall), and stage one aluminum heads with 11.5:1 compression if I had that engine to do over. That combination would have close to 600 HP, run on pump gas and have decent street manners IMHO.
