Here's a couple of my engine results for comparison purposes...
*434 ci FE, 422 hp @ 5500, 467 lb-ft @ 4000. 4.165 x 3.980, factory CJ crankshaft, Scat H-beam rods, Diamond pistons, 9.8:1. Comp Cams hydraulic roller, 227/233 @ .050", .576" lift, 112 LSA. Factory CJ heads, Ferrea valves, valve job only. Factory CJ intake manifold. Holley 750 mechanical secondary carburetor.
I think the heads flowed around 250 @ lift on that one.
*428 ci FE, 533 hp @ 6400, 472 lb-ft @ 5400. 4.130 x 3.980, Scat cast crankshaft, Scat H-beam rods, Probe pistons, 11:1. Comp Cams solid roller, 248/254 @ .050", 110 LSA, 110 ICL, .676"/.680" lift, Keith Craft Stage 1 Edelbrock heads, Dove Tunnel Wedge, Road Demon 625 carburetors.
Solid roller, pulling to 6500 with 270-280-ish heads and still didn't hit the 550 mark.
*427 ci FE, 510 hp @ 6100, 511 lb-ft @ 4200. 4.250 x 3.780, factory 391 crankshaft, BBC rod journals, Oliver rods, Race-Tec pistons, 11.5:1. Bullet solid flat tappet, 252/260 @ .050", 106 LSA, 104 ICL, Lawes Mayfield ported factory C3 LR heads, Lawes Mayfield ported factory LR 2x4 intake. Holley 600 carburetors.
*427 ci FE, 476 hp @ 5700, 489 lb-ft @ 4400. 4.236 x 3.780, factory 427 $ crank, Scat H-beam rods, Diamond pistons, 10.7:1. Bullet solid flat tappet, 240/246 @ .050", 108 LSA, 103.5 ICL, .620"/.614" lift. Edelbrock heads (out of box with good valve job), Blue Thunder 1x4 intake. Holley 750 carburetor. Stuska dyno.
And here's what it takes to hit 600 lb-ft of torque on the dyno I use:
*487 ci FE, 536 hp @ 6000, 583 lb-ft. 4.270 x 4.250, Scat cast crankshaft, Scat H-beam rods, Diamond pistons, 10.5:1. Comp Cams hydraulic roller, 245/248 @ .050", .634"/.634" lift, 110 LSA. Edelbrock RPM heads with valve job, Edelbrock Performer RPM intake, Quick Fuel BD-850 carburetor.
*501 ci FE, 580 hp @ 6000, 615 lb-ft @ 4000. 4.270 x 4.375, RPM forged crankshaft, Scat H-beam rods, Race-Tec pistons, 10.3:1. Crane hydraulic roller cam, 254/260 @ .050", .655"/.655", 112 LSA, 107 ICL. Joe Craine ported Edelbrock cylinder heads, Joe Craine ported Performer RPM intake. Quick Fuel Q-950 carburetor.