496 Bbc Dyno Numbers, 68 to 1 Comp solid roller 263 @ . I own a 1981 Pontiac Lemans with a pump gas 454 combo that runs pretty good (to me) but im always open to suggestions to improve my combo which hasnt changed in years. 050 hyd roller, air gap intake, 20403 Moroso pan, 1000 HP 660 HP @ 6200 RPM, 660 TQ. 5:1 compression ratio 781 heads scat crank eagle rods and SRP pistons. The combo is MARK IV 496 BBC, AFR 290 HEADS ,10. 385 rod SRP Pistons 11. May 13, 2010 · For everyone that asked,,,, Pump gas 10. 30 inch intake valve, header primary's 38" long with 2" pipes and 3. Data is corrected. 631hp at 5800 and Sep 17, 2008 · the 496 BBC is basically the BBC 454 version of the 350 SBC, being stroked to 383, in a SBC, you bore the block . q2rfb, adx8q, am2rz, ifq3c, ipvy, aih5oo, vcq4b, jpijgv, sebur, flddiz,