We have a guy here in UK who posts on here, runs a 580 wedge, 12.5:1, ported -13's, 385CNC roller of approx 750 lift, TR with 2 x 1150's and according to his weight/mph he is making around 895fwhp....perhaps he'll see this and post up maybe something I missed. Hi Les,  The 580 wasn't built as an all out effort but as a reliable low maintenance bracket motor, we've learned some stuff along the way and got it running good without loosing any reliability. You are correct, it's just under .750 net lift on the inlet and .730 exhaust with 1.6 arms (tempted to go to 1.7's but it just ain't that easy) It picked up some running low tension rings and a vac pump. We also found a couple of things at the end of the 2019 season so we may pick up a little next time out but we'll see. The OPs engine should easily crest 800hp with a couple of tricks maybe 850, an all out effort and some real attention to detail should see 900hp IMHO
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials.
9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge.
RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
| 
