Think i found my problem
04-06-2010, 03:28 PM
#11
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After pulling heads off we found many indications of reversion, the ehaust vave seat had to be touched up quit a bit due to reversion to get it to seat again. yes i did a leak down last year after all work was done and all was good, 1st couple time out the boat went 87 mph into the rev limiter and then was down to 81mph and rpm was way dawn as well. both motors show indication of reversion in the exact same places, never an issue till putting in the bigger cams, what exhaust would you guys recommend now with out going dry to the tip becaust that will be to loud where i boat, thunderstruck what exhaust and cam are you running.
I would call Bob Madara and discuss the reversion problem. Cams are cheaper than exhausts.
I have AFR heads so don't know if we are in the same ball park flow wise but my cams have a little less duration and lift than the stock 500HP carb heads. 605 HP at 5600 rpm uncorrected.
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04-06-2010, 05:30 PM
#12
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Those tails have the mod by Gil to help prevent reversion ? I had a set before that had the mod done, don't know if it would be enough to help with your cam.
04-06-2010, 05:38 PM
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04-06-2010, 06:24 PM
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Who degreed in the cams when you went to 741s? What ICL were they set to, straight up? You need to make sure your EVC degrees do not get too large. A couple degrees retarded makes a big difference with reversion, a couple advanced would help. I'd hunt up some KE full headers with inserts to make the tails dry.
04-07-2010, 09:41 AM
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Gils have 2 styles of risers. The original low riser was on early HP500's which were prone to reversion. Gil redesigned the riser and made it a couple of inches higher to solve that problem. Maybe the taller risers would help.
