Yep, what they said...call Brian. Depending on your goals, these are GREAT heads. If you're looking for 750 HP? No. But they can support in excess of 600 easy. The best part is the cost...

My REAL WORLD experience was a pair bought from NOT Brian in the LA versions with a 2.02 intake, Comp 26995 Beehive springs, ret, locks ready to run. We took them apart and chucked on a known bench to see the flow #'s. The number's really don't matter as your actual mileage (and flow #'s) will vary. But I will tell you that with a GOOD VJ added, a little (very little) blending of the guide boss and unshrouding of the chamber, they improved about 10 cfm to 268 @ .600", the same at .650" and going backwards above that. We called it a success and plopped them on a motor for the Duster and here are the specifics:

*416
*12.2:1 Flat top (KB Forged)
*SCAT I beams
*Eagle forged crank
*The aforementioned RHS heads
*Comp Stainless 1.5 rockers
*Custom Bullet solid (non-roller) cam (268/276 @ .050 w/.585 net lift)
*Old Victor intake (with a minimal plenium blend)
*REALLY Old 800 Holley (tuned it to 848 on our bench)
*2" open spacer (because that's what fits the air cleaner/carb/scoop/seal deal)
*Hooker 1 3/4 headers
*Dynomax 3" Bullet muffs

904 (standard low gear)
8" Converter (5200 real flash in good air)

4.56
29.5 tall slick

dead on 3100# race weight.

Cal Mono Springs/Cal tracs...

Best so far: 10.14 @ 128 (107 in the 1/8) with a 1.42 60' best. If I can just get that 60' to a solid 1.35...