I am tempted if someone wants to load intakes and carbs to see, I would run with hatch off boat for clearance, if it went 4 mph faster I would find a way to make it work.... Then again Dyno shows I'm using 850 CFm...... So not sure if it's the issue.

In response to post just above , hook vacuum gauge under carb and see what the vac is at WOT andtop rpm. This will tell you if carb is a decent restriction or not. Most carbs don't flow as advertised...just to add to confusion.

Not sure if I'm gonna get anymore trips out due to no reverse, unless I chance it one more time lol

Those cams were making 650 hp with just out of the box pro one 310's. I would amagine another 50 hp plus if heads and intakes were reworked.

I installed same cams and heads in/on a pair of 496's for project and made 600 hp plus @ 5,800 however used solid springs and lifters do to a combination of spring and hyd lifter issue that we discovered on the dyno. I didn't wanna mess around and take a chance on another set of hyd lifter failure. Lifters initially used were crower 66321. How much advance was ground into the cams initially I don't recall.

Sounds like that might be a little more imminent at the moment.

Well, forward works fine, I am told it may be a stuck valve, fluid looks good... I am going to look into that this week....

Put some Lucas in it. Chit works miracles.

Sounds like your set on drive back ups and prolly trans as well but just in case I have 4 on the shelf. C72's. Two fresh rebuilds and two that came out of a running boat.

Shop by me recently built a 496 ci. 10.2:1, GM Rect port iron heads with a nice valve job, no port work. Cams were hyd roller 242/254 112 LSA, .679/.679 lift. Victor JR intake, holley EFI . Peak was 645HP at 6200, 595FT lbs at 5000, still making 575ft lbs at 4000. Pretty darn good considering the GM iron heads , not even ported imo.

HP is really not much greater when considering the differences - 10;1 compression/dominator. And the Crane 651 cam was mentioned in this thread as a go to 540 cam.