Cam and valvetrain longevity....??? low duration high lift...
#521
Registered
I've used its bigger brother on tall deck motors with great results. I'm doing a pair of 555 budget motors as soon as the weather changes. I'll use the sv565 intakes and some top secret cams I designed on my own should make 725ish hp.
#525
Gold Member
Gold Member
Thread Starter
Join Date: Oct 2005
Location: Olmsted Falls,Ohio Marblehead,Oh
Posts: 11,638
Likes: 0
Received 209 Likes
on
133 Posts
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
#526
Registered
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
#527
Registered
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.
#528
Gold Member
Gold Member
Thread Starter
Join Date: Oct 2005
Location: Olmsted Falls,Ohio Marblehead,Oh
Posts: 11,638
Likes: 0
Received 209 Likes
on
133 Posts
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.
#529
Registered
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.