Cam and valvetrain longevity....??? low duration high lift...
09-26-2016, 05:20 AM
#525
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Port engine should come out in the next couple days....at that point I will at least pull a valve cover and run a machinist edge across cylinders to see if exhaust seats are getting pounded into the head... from the things I am told the issues arise between 50-70 hours.. I am at 65 or 67, cannot remember
09-26-2016, 06:27 AM
#526
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Port engine should come out in the next couple days....at that point I will at least pull a valve cover and run a machinist edge across cylinders to see if exhaust seats are getting pounded into the head... from the things I am told the issues arise between 50-70 hours.. I am at 65 or 67, cannot remember
09-26-2016, 06:31 AM
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I think what we have learned here, is that
A ''custom high lift cammed" 540ci , with AFR 325 heads, is no better, than a 565ci, with good flowing chinese 320cc heads, and a low lift hyd roller cam. The boat lost acceleration by dropping 25 cubes, and a longer duration cam. It gained nothing for top speed either.
The old 4.375x4.530 combo , with a refresh, and a cam upgrade, probably would have been the best bet.
I'm really not surprised by any of this. The procomp 320 heads he had, were if I recall, knock off's of the old pro topline/RHS/Engine quest line of heads. In stock form, they dynoed around 600hp on tims 565. Then later, he had Gellner do a valve job and cleanup on them. That there probably helped them out a little, and had he redynoed, he probably would have been very close to his "630HP" he has from bobs combo, with a bit more torque down low from the added cubes and smaller cam. Those procomp heads castings were not very good quality, but like everything pro comp did, was take a good design, and copy it. They made some decent power, and probably flowed really close to the afr 325's after the tune up they had.
I don't think theres going to be any magic here, to get him the results he wants, whether it be from a spacer, intake swap, or even cam swap. I'd focus on the health of the engine, making sure all is well there, and keep on boating until you can strap a blower on the thing, and get the results you want.
A ''custom high lift cammed" 540ci , with AFR 325 heads, is no better, than a 565ci, with good flowing chinese 320cc heads, and a low lift hyd roller cam. The boat lost acceleration by dropping 25 cubes, and a longer duration cam. It gained nothing for top speed either.
The old 4.375x4.530 combo , with a refresh, and a cam upgrade, probably would have been the best bet.
I'm really not surprised by any of this. The procomp 320 heads he had, were if I recall, knock off's of the old pro topline/RHS/Engine quest line of heads. In stock form, they dynoed around 600hp on tims 565. Then later, he had Gellner do a valve job and cleanup on them. That there probably helped them out a little, and had he redynoed, he probably would have been very close to his "630HP" he has from bobs combo, with a bit more torque down low from the added cubes and smaller cam. Those procomp heads castings were not very good quality, but like everything pro comp did, was take a good design, and copy it. They made some decent power, and probably flowed really close to the afr 325's after the tune up they had.
I don't think theres going to be any magic here, to get him the results he wants, whether it be from a spacer, intake swap, or even cam swap. I'd focus on the health of the engine, making sure all is well there, and keep on boating until you can strap a blower on the thing, and get the results you want.
09-26-2016, 07:10 AM
#528
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Spot on... Gonna do some checking when engine is out and see what things look like ...
I think what we have learned here, is that
A ''custom high lift cammed" 540ci , with AFR 325 heads, is no better, than a 565ci, with good flowing chinese 320cc heads, and a low lift hyd roller cam. The boat lost acceleration by dropping 25 cubes, and a longer duration cam. It gained nothing for top speed either.
The old 4.375x4.530 combo , with a refresh, and a cam upgrade, probably would have been the best bet.
I'm really not surprised by any of this. The procomp 320 heads he had, were if I recall, knock off's of the old pro topline/RHS/Engine quest line of heads. In stock form, they dynoed around 600hp on tims 565. Then later, he had Gellner do a valve job and cleanup on them. That there probably helped them out a little, and had he redynoed, he probably would have been very close to his "630HP" he has from bobs combo, with a bit more torque down low from the added cubes and smaller cam. Those procomp heads castings were not very good quality, but like everything pro comp did, was take a good design, and copy it. They made some decent power, and probably flowed really close to the afr 325's after the tune up they had.
I don't think theres going to be any magic here, to get him the results he wants, whether it be from a spacer, intake swap, or even cam swap. I'd focus on the health of the engine, making sure all is well there, and keep on boating until you can strap a blower on the thing, and get the results you want.
A ''custom high lift cammed" 540ci , with AFR 325 heads, is no better, than a 565ci, with good flowing chinese 320cc heads, and a low lift hyd roller cam. The boat lost acceleration by dropping 25 cubes, and a longer duration cam. It gained nothing for top speed either.
The old 4.375x4.530 combo , with a refresh, and a cam upgrade, probably would have been the best bet.
I'm really not surprised by any of this. The procomp 320 heads he had, were if I recall, knock off's of the old pro topline/RHS/Engine quest line of heads. In stock form, they dynoed around 600hp on tims 565. Then later, he had Gellner do a valve job and cleanup on them. That there probably helped them out a little, and had he redynoed, he probably would have been very close to his "630HP" he has from bobs combo, with a bit more torque down low from the added cubes and smaller cam. Those procomp heads castings were not very good quality, but like everything pro comp did, was take a good design, and copy it. They made some decent power, and probably flowed really close to the afr 325's after the tune up they had.
I don't think theres going to be any magic here, to get him the results he wants, whether it be from a spacer, intake swap, or even cam swap. I'd focus on the health of the engine, making sure all is well there, and keep on boating until you can strap a blower on the thing, and get the results you want.
09-26-2016, 08:35 AM
#529
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After a season on a new set of aluminum heads we have found it very beneficial to pull the heads and do a valve job. Even with very mild cams it seems as though things move around. After the first go round things seem to settle down and be good to go for awhile... If I was in your shoes I would just yank them and go through them. If you have mls gaskets don't hesitate to re-use.
09-26-2016, 09:31 AM
#530
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I have never heard to fix aluminum heads after one season, ever.... I just don't see how that can be right
