Mistress repower #2 begins....
#721
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To be honest, from a power producing standpoint, I don't think the new builds are that much better than the old engines. Quality wise, you now have some better components. Better blocks, cranks, rods, pistons, carbs, heads, lifters etc etc.
Guys don't wanna believe it, but those old procomp heads gellner prepped, probably flowed pretty darn well. Sure they are chinese castings that had issues, but they were decent flowing heads, and I'm sure after Dean went thru them, he improved them flow wise a bit. From a power standpoint, I don't believe switching to the AFR's and a new cam, was gonna transform it from mild to wild.
The old builds made 600ish HP if I recall, around 5300RPM, and that was prior to dean doing some work on the heads. The new builds, while capable of probably 650-675hp, my guess is that would be around 6000RPM. At 5300RPM, you're probably making around the same power, as the old engines. To see a gain performance wise, you're probably gonna have to step down in pitch, to get the R's up. That will maybe net you a slight increase in top speed, and a decrease in cruise speed at 3500-4000RPM.
I wouldn't beat yourself up about it. The goal was solid engines that stay together. I'm sure you'll find a little more speed in it with some more tuning and prop work, etc. The mistress is a tank of a boat, and to get mph it takes alot of power. Many times on oso we debate things like a couple degrees of cam duration, .030 worth of lift, half point of compression, and so on, as if its the end all be all. But in the real world, many times, that little stuff, isn't worth chit on the speedo.
Next summer, bolt some 8-71's on those things
Guys don't wanna believe it, but those old procomp heads gellner prepped, probably flowed pretty darn well. Sure they are chinese castings that had issues, but they were decent flowing heads, and I'm sure after Dean went thru them, he improved them flow wise a bit. From a power standpoint, I don't believe switching to the AFR's and a new cam, was gonna transform it from mild to wild.
The old builds made 600ish HP if I recall, around 5300RPM, and that was prior to dean doing some work on the heads. The new builds, while capable of probably 650-675hp, my guess is that would be around 6000RPM. At 5300RPM, you're probably making around the same power, as the old engines. To see a gain performance wise, you're probably gonna have to step down in pitch, to get the R's up. That will maybe net you a slight increase in top speed, and a decrease in cruise speed at 3500-4000RPM.
I wouldn't beat yourself up about it. The goal was solid engines that stay together. I'm sure you'll find a little more speed in it with some more tuning and prop work, etc. The mistress is a tank of a boat, and to get mph it takes alot of power. Many times on oso we debate things like a couple degrees of cam duration, .030 worth of lift, half point of compression, and so on, as if its the end all be all. But in the real world, many times, that little stuff, isn't worth chit on the speedo.
Next summer, bolt some 8-71's on those things
#722
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To be honest, from a power producing standpoint, I don't think the new builds are that much better than the old engines. Quality wise, you now have some better components. Better blocks, cranks, rods, pistons, carbs, heads, lifters etc etc.
Guys don't wanna believe it, but those old procomp heads gellner prepped, probably flowed pretty darn well. Sure they are chinese castings that had issues, but they were decent flowing heads, and I'm sure after Dean went thru them, he improved them flow wise a bit. From a power standpoint, I don't believe switching to the AFR's and a new cam, was gonna transform it from mild to wild.
The old builds made 600ish HP if I recall, around 5300RPM, and that was prior to dean doing some work on the heads. The new builds, while capable of probably 650-675hp, my guess is that would be around 6000RPM. At 5300RPM, you're probably making around the same power, as the old engines. To see a gain performance wise, you're probably gonna have to step down in pitch, to get the R's up. That will maybe net you a slight increase in top speed, and a decrease in cruise speed at 3500-4000RPM.
I wouldn't beat yourself up about it. The goal was solid engines that stay together. I'm sure you'll find a little more speed in it with some more tuning and prop work, etc. The mistress is a tank of a boat, and to get mph it takes alot of power. Many times on oso we debate things like a couple degrees of cam duration, .030 worth of lift, half point of compression, and so on, as if its the end all be all. But in the real world, many times, that little stuff, isn't worth chit on the speedo.
Next summer, bolt some 8-71's on those things
Guys don't wanna believe it, but those old procomp heads gellner prepped, probably flowed pretty darn well. Sure they are chinese castings that had issues, but they were decent flowing heads, and I'm sure after Dean went thru them, he improved them flow wise a bit. From a power standpoint, I don't believe switching to the AFR's and a new cam, was gonna transform it from mild to wild.
The old builds made 600ish HP if I recall, around 5300RPM, and that was prior to dean doing some work on the heads. The new builds, while capable of probably 650-675hp, my guess is that would be around 6000RPM. At 5300RPM, you're probably making around the same power, as the old engines. To see a gain performance wise, you're probably gonna have to step down in pitch, to get the R's up. That will maybe net you a slight increase in top speed, and a decrease in cruise speed at 3500-4000RPM.
I wouldn't beat yourself up about it. The goal was solid engines that stay together. I'm sure you'll find a little more speed in it with some more tuning and prop work, etc. The mistress is a tank of a boat, and to get mph it takes alot of power. Many times on oso we debate things like a couple degrees of cam duration, .030 worth of lift, half point of compression, and so on, as if its the end all be all. But in the real world, many times, that little stuff, isn't worth chit on the speedo.
Next summer, bolt some 8-71's on those things
#723
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I wouldn't beat yourself up about it. The goal was solid engines that stay together. I'm sure you'll find a little more speed in it with some more tuning and prop work, etc. The mistress is a tank of a boat, and to get mph it takes alot of power. Many times on oso we debate things like a couple degrees of cam duration, .030 worth of lift, half point of compression, and so on, as if its the end all be all. But in the real world, many times, that little stuff, isn't worth chit on the speedo.
Next summer, bolt some 8-71's on those things
#724
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do you have nose cones? I know your not in the 80's but did it on a trs boat that did 70 ish and it picked up 1-2 no BS. What direction are the props spinning?
#727
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I am confident these engine would make the 675 or so at 5800-6000 rpm but I was hoping to use existing prop to see it I don't wanna put on 21p to do it
#729
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Try taking vacuum readings at WOT, that will rule out a restriction in airflow.
EDIT: Could you play with your cam timing to bring your torque curve down a little? Might help you get a little more out of it without breaking the bank.
EDIT: Could you play with your cam timing to bring your torque curve down a little? Might help you get a little more out of it without breaking the bank.
Last edited by donzi matt; 07-07-2015 at 08:17 AM.
#730
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I really think it's a powerband issue and what mild thunder posted, 2 local buddy's agree with that also