I remember the guy who originally built cig rockets 540's. They were done here in chicago area. Dynoed at fast times motorworks. If I recall, they made in the 660hp range at 5500 , with race car headers, and no accessories, and some trick valves and head flow work/testing.

Here's a thread where he ran the new engines, and got 68mph (not propped right yet he said). Another guy with 700's, and #3 ssm's, says 72-75. Another guy says 600's, trs, and runs 64mph.
http://www.offshoreonly.com/forums/c...w-engines.html

Cigrockets builds
http://www.offshoreonly.com/forums/g...ml#post1030481

gotcha, just adding info to look at. was not sure I know it depends on cam bleedoff too.

I thought Cigrocket told me like 680 HP, not sure I can try to see where...

read that thread, how can these guys only be going mid to high 60's with 540's? I was stoked when mine went 73.7 with old engines... they were 598 hp 565's... with 460's with merlin heads and 420 cams 800 holleys mine went 64 best ever... best ever with these new 540's was 73.4 last summer, 73.2 this summer...

I guess in the end if its low 70's that is is what it is, thought with 630 HP in dyno trim VS 598 HP header trim the boat would not go backwards that's all...

If I were a betting man, I'd be willing to bet, if Tim had dyno'd his engines, with no accessories, some 2 1/8, or 2.25 dyno headers, with a decent collector setup, dumping into some big ole straight flex pipes, some tweaking on the dyno with carb spacers and stuff like that, he would have got much closer to his promised setup. Maybe not hit the target, but not 70hp away.

I'm going to stick with my gut feeling advice wise, and say that ,I feel his exhaust system is hurting him, he'd be better off with a dominator carb (got blasted for suggesting that during his build here), and a little more camshaft. Not a ton, but a little more.

If his boat was mine, and I was going to be making changes, I would be looking for a decently priced set of used headers, a different camshaft, taking the heads off, getting a nice valve job done with a back cut on the intake valves, ditching the MSD ready to run distributors, and figuring a way to get as much fresh air into that bilge as possible. I'd also be putting the scorpion rockers on ebay. JMO.

I'd forget about what everyone else is doing. If I followed what everyone else was doing with their 454's, they'd have been in the dumpster a long time ago.

Old engines

565 ci
9.5:1
Pro comp 320cc
Cam (see pic)
Same intakes I have now
800holleys

Also attached Dyno sheet from them engines
[ATTACH=CONFIG]559644[/ATTACH][ATTACH=CONFIG]559647[/ATTACH]

Looking at your old sheets vs new sheets, looks like raw torque wise, in the 5200-5400 range, you aren't that far apart. 20ft lbs , isn't going to net several mph in a old mistress.

Bottom line, as I have said before, you went from a 565ci, to a 540ci. 25 cubes is alot. The 565's had procomp heads with a good valve job by gellner. That was AFTER they were dynod. So those numbers you are comparing, could have made them even closer power output wise, than what you're seeing on the dyno sheets. 25ci more, whether that thing had too small of a cam, too big of a cam, or a banana up its azz, they simply weren't worlds apart power wise. Its easy to see gains, when you go from a pair of 502 mags, to some 540 AFR headed, custom cammed, madera specials. Not so much, when you're already in the aftermarket headed , custom build to custom build, similar cube range. While those procomp heads had chit castings, they moved some air, especially after being gone thru . Those 325 AFR's, vs a set of gone thru 320cc pro comps, flow wise and performance wise, ehh, I'm not buying that its gonna be a night and day improvement. If I recall, those procomps were copies of the RHS heads, or trick flow heads, or something like that, which were dam good heads .

Even at 1.16HP per ci, 25 cubes might be worth, 30hp right off the bat.

Had to have dinner...so,backto it....On the other hand, 502-509's with AFR 315's and the 741 have dyno'd 600-620hp. Vic JR, 950 4150's. There have been plenty of these done.

Edit in: dyno headers.

600hp 502 = 1.19HP per ci

1.19HP x 540 = 642HP.

Throw in a little frictional loss from the added stroke, hmm. lol

What RPM was that at in the 502 combos SB?

What did you have for dinner? You eat late like myself I see.

yea, I hear ya, guess with a tad more HP figure if nothing else it would still go same easily... oh well...

took trans shift valve out tonight, gonna toss my valve from spare trans in tomorrow and see if I have reverse, that will determine what I do with engines...

His wife is going to divorce him thou then he`ll only have half a boat which isn`t all bad.... much cheaper to only buy new parts for one motor.