I love my 393w and would like a 520 inch version of it. My 393 has a 3.850" stroke with " rod. With a hydraulic roller cam: 232/240 @ .050" 545" lift-112'. It has AFR-185 heads, edelbrock air gap intake with a Demon 750 with vac 2nd. What I am interested for my '73 Mach-1 is a 520 bbf: 4.3000" stroke and 6.800" rod Air gap intake and aluminum cobrajet heads. As for the cam, I'm thinking hydraulic roller 242/248 @ .050" about .540/.550-112'
I like the characteristics of my 393, but would like more power and have always been interested in a big block..
I would go for a higher lift cam for the big block. Cobra Jet heads will support higher lifts. Big inches will tame the cam for sure, I would go even something like this:
Howards, Hydraulic Roller Camshaft, Ford BB 429-460
243655-10
Ford BB 429-460 1968-1995
Advertised Duration: 300/300
Duration @ .050": 247/247
Valve Lift w/1.73 Rockers: .623/.623
Lobe Separation Angle: 110
Intake Centerline: 106
Valve Lash: Hyd./Hyd.
3000-6800. Lopey idle, street/strip, good mid range horsepower. Best with 3500+ stall.
or with the bigger one:
Howards, Hydraulic Roller Camshaft, Ford BB 429-460
243545-10
Ford BB 429-460 1968-1995
Advertised Duration: 302/308
Duration @ .050": 249/255
Valve Lift w/1.73 Rockers: .652/.652
Lobe Separation Angle: 110
Intake Centerline: 106
Valve Lash: Hyd./Hyd.
3200-7000. Rough idle, hot street/bracket, good torque & upper mid range. 11.5:1+, 3800+ stall.
Take minimum of 500 rpm off the max rpm are you're close to the true rpm area. Big inches will tame these beast's out.
One very good possibility is to use some good reputable engine builder to spec you custom camshaft for your exact needs.
What comes for the same degree & lift cams sbf vs. bbf, I would say as the Tommy does, but o dyno won't nessecary notice the diffrence. You can though notice it too, since the head layout = wedge and bigger borespacing can give advantage.