Gen VI 502's.4.250 stroke,6.385 rods.No overbore.Compression around 9.3:1
What head CC's 320?I do have 2 sets of factory ported 088 500EFI heads or is any Aluminium head better than the 088?
What HP difference will I see using a 500 731 cam over the 741 525 cam?
If I do use the 731 am I able to use the net lash non adjustable valve train on a gen VI?

your 1 step from a 540.........what are you using for fuel supply

I did the 731 cam with AFR heads and Victor Jr intake 585 hp/611 tq @ 5200, also added the Holley snipper.

i have built several with the 741 cam and engine quest 320 heads,600 hp all day long.

You cannot use the non adjustable valve train for anything except the stock magnum cam.
You need rocker arm conversion studs and roller rocker arms for either cam.

Yes about 8 cubes,
Fuel,Carb 950 I reckon.Aeromotive pumps.
So go straight for a 741 Crane?
Longer travel lifter and roller rockers.

My 540's I went with the 731 cam and made 615hp/689tq. Dart pro 1 325cc heads, dart intake and quick fuel 1050 carb. Definitely on the small side for a 540 but behaves very well and pulls strong up to 5500 rpm.

Would there be any reason to go with the 731 instead of the 741?
Or is there HP to be gained.

The 741 will definitely make more power than the 731 and is a better choice.

As stated above Id run the the 741 cam and the EQ heads as Mike said if running in salt, if you're running in freash water might look at the AFR 305 or the Brodix line up