[Anthony]

Since you already have the LeMans crank, I would just use that. Obviously, if you wanted your engine to be a true 427, then use the stock stroke crank.

If you had to buy a crank, then I would get the stroker crank, either 3.98, or new scat stroker ?4.25". Any time you stroke any engine, with all other things being equal, you will always make more max torque and max Hp. Granted, the output per cubic inch may be a little less, but overall power output will be greater at all rpms, except maybe at the very top extreme. More ci will also tame the cam a little bit.

I can't remember if the LeMans crank was one of those "heavy" forged cranks. Some drag racers would use the cast 390 cranks (same stroke) as they were lighter and would rev faster than some of the forged ones, for better acceleration. So, maybe, a cj crank may be lighter than a LeMAns crank, but again, I'm not sure about that.

Ford built the 427 for NASCAR racing, which had a 7 liter limit displacement. Ford put the bigest pistons in the FE, with the appropriate stroke to get to 427 ci. The bigger bore allowed bigger valves for better breathing and top end HP, what was needed for Nascar. If Ford could have put even biggger pistons in it, they would have, but they were at the limit for the FE block. They changed that when they designed the 429/460 block with larger bore spacing allowing even a bigger piston and shorter stroke to meet the 427 ci displacement limit.

The 428 engine was a cheaper block to cast compared to the 427 block which required special casting processes to get the water jackets right. With the 428 engine, you got the displacement of 7 liters, without the more expensive cost of the 427 block. I also believe the slightly smaller bore of the 428 gave slightly better emissions, as it had better combustion with a smaller diameter bore, and would be perfect for passenger cars.

A billet crank, other than being the most expensive, is generally the lightest, and is available in just about any stroke you want.