Cam and valvetrain longevity....??? low duration high lift...
#141
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I think the fact tim dynoed in full trim, with wet stainless marine manifolds, was one of the reasons his power is down compared to a few others with similar combos. I'd bet that with a cam that has a bigger split, would have helped , especially when the exhaust system isn't ideal for big power numbers.
Single pattern camshafts, can make some good torque numbers, and a good torquey street engine, but suffer in the upper rpm. Bigger splits in the duration, can give up some low end to a single pattern, but usually pull better in the upper rpm range.
Without trying a different cam, its pretty much all speculation.
#142
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#143
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Found this on speedtalk on a 540 thread
by badss540 » Fri Dec 03, 2010 9:49 am
My 540 (built at SSRE) had 10 to 1, dart 325's,dart manifold,1090 BG carb,Merlin 3 block, (Crane)651 hyd roller and made 691 at the crank..
My 540 (built at SSRE) had 10 to 1, dart 325's,dart manifold,1090 BG carb,Merlin 3 block, (Crane)651 hyd roller and made 691 at the crank..
#146
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yes specs would be nice, because bob told me 700 ish all day long and clearly it's not, also I doubt hes at 242/248 that's close to mine.... this is what kills me, 3 Bob cam guys boast how great the results are, yet I have not seen one cam spec, or full combo posted, I doubt that dudes making 73-760 HP also, I nearly GAURANTEE that... especially if cam is anywhere close to mine.. Offshore excursion is only at 750hp with very nicely built 472.s even.... dyno proven... I get dyno is not everything but it is accurate for HP facts, if you donlt dyno your guessing at what you got..
Cam Specs: 7/4 2/3 firing order swap, Hyd. roller
Lobe Sep: 113.1
valve overlap:19.6
INT
open 12.6 btdc
c/l 109.1 atdc
close 50.9 abdc
duration 243.5
lobe lift .40024 in
valve lift .6804 in
lobe area 32.61
EXH
open 63.2 bbdc
c/l 117.1 btdc
valve close 7 atdc
duration 250.2
lobe lift .38996 in
valve lift .66293 in
lobe area 32.69
Last edited by Gimme Fuel; 09-19-2016 at 07:52 AM.
#148
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I tried something this summer that made a bigger difference than I would have thought. I've been running a JOMAR tapered Phenolic 1" spacer, this summer I added a 1" open spacer under that and I could feel the difference over 5k. I'm running a 524 with 10.1:1 compression, AFR 315 with CNC Bowl and chamber, Brodix HV2000 intake, Lightning headers, The cam is a custom Comp hydraulic with .623/.612 and 242/252 @ .050. You could have some weird flow issue going on that's killing your power. I matched the runners in the head and intake to maintain a consistent taper throughout the runner. Some intakes make the port opening small so you can match to your gasket/heads. The sudden change in runner dimensions can cause pulse issues that can dramatically effect power. I never dynoed my motor but I run 90 in a velocity 280 with 4 adults and a full load and almost 6000rpm.
#149
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Location: Olmsted Falls,Ohio Marblehead,Oh
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Like I said I doubted it, never said for sure can't happen, I didn't see any specs until now or missed them...
Tim my cam is bigger than yours. I have more head than you, more compression than you, more intake than you, more throttle body flow than you. You also are saddled with low hatch clearance and smaller carbs, that causes restrictions. What more of a full combo can I post? AFR 335 full cnc heads, 10.2 CR, Edelbrock 454-R dominator flange intake, 1" open spacer with 2100 cfm throttle body, Holley HP distributorless EFI with LS3 CnP ignition. I have no doubt on a dyno I could make the projected numbers on dyno headers and conditions. I run Eddie Marine manifolds with the standard long risers. I also run full accessories. I have no doubt IN BOAT the engine will crack 700 hp mark based on achieved speeds.
Cam Specs: 7/4 2/3 firing order swap, Hyd. roller
Lobe Sep: 113.1
valve overlap:19.6
INT
open 12.6 btdc
c/l 109.1 atdc
close 50.9 abdc
duration 243.5
lobe lift .40024 in
valve lift .6804 in
lobe area 32.61
EXH
open 63.2 bbdc
c/l 117.1 btdc
valve close 7 atdc
duration 250.2
lobe lift .38996 in
valve lift .66293 in
lobe area 32.69
Cam Specs: 7/4 2/3 firing order swap, Hyd. roller
Lobe Sep: 113.1
valve overlap:19.6
INT
open 12.6 btdc
c/l 109.1 atdc
close 50.9 abdc
duration 243.5
lobe lift .40024 in
valve lift .6804 in
lobe area 32.61
EXH
open 63.2 bbdc
c/l 117.1 btdc
valve close 7 atdc
duration 250.2
lobe lift .38996 in
valve lift .66293 in
lobe area 32.69
#150
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Location: Olmsted Falls,Ohio Marblehead,Oh
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Not entirely sure how to target that, but I GAURANTEE alternator and sea pump and Olmsted dry exhaust is not 70 HP
I was told maybe 30 hp difference
I was told maybe 30 hp difference