Time for more power
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Because Darth came up with this grind along with SpeedTigger from the boar at Cam motion as the grind I need for best results. I'll take these guys word that this will build more power for my combination and that the exhaust split I had was not optimal for my set up.
Here's what I was thinking when we came up with the new spec, and maybe this will make some sense.
* This motor basically made the same power and torque (or within close enough for government work) on two different head platforms (ported LS3 and Mast LS7), multiple intakes, multiple compression ratios, multiple outings at the track, and it seemed like there just wasn't more to be found. And I was seeing similarly sized cams but less split (246/253 type stuff) makin similar power on other 427 builds, so I reasoned that the intake lobe was the bottleneck of the build.
* We actually need it to build more torque, not rev higher. If you look at the valve events on the old cam vs the new cam, true, the exhaust lobe doesn't change. But all that added duration on the intake side went into overlap, and here is where I think the critical change occurred. The overlap on the old cam was biased 4 degrees to the exhaust side. Many times, people look at the LSA spec and see "1xx +y" and think the cam is advanced. What makes a cam technically advanced or retarded in my opinion is the overlap bias. Everything about this cam says it was behaving as though it was retarded. Even though it was degreed when installed. It behaved as though retarded. I fundamentally believe that this is a function of overlap bias.
* The new spec rebiases the overlap to the intake side by four degrees, which will in my opinion, result in much harder hitting midrange. At 12.5 compression, this should put him right at 8.73 dynamic, AND with that added intake duration, should really hit much harder in the midrange, and especially hit the converter harder on the upshift, which was what I think was limiting him at the track. Should still carry into the upper 7000's
Feel free to flame away, guys.
* This motor basically made the same power and torque (or within close enough for government work) on two different head platforms (ported LS3 and Mast LS7), multiple intakes, multiple compression ratios, multiple outings at the track, and it seemed like there just wasn't more to be found. And I was seeing similarly sized cams but less split (246/253 type stuff) makin similar power on other 427 builds, so I reasoned that the intake lobe was the bottleneck of the build.
* We actually need it to build more torque, not rev higher. If you look at the valve events on the old cam vs the new cam, true, the exhaust lobe doesn't change. But all that added duration on the intake side went into overlap, and here is where I think the critical change occurred. The overlap on the old cam was biased 4 degrees to the exhaust side. Many times, people look at the LSA spec and see "1xx +y" and think the cam is advanced. What makes a cam technically advanced or retarded in my opinion is the overlap bias. Everything about this cam says it was behaving as though it was retarded. Even though it was degreed when installed. It behaved as though retarded. I fundamentally believe that this is a function of overlap bias.
* The new spec rebiases the overlap to the intake side by four degrees, which will in my opinion, result in much harder hitting midrange. At 12.5 compression, this should put him right at 8.73 dynamic, AND with that added intake duration, should really hit much harder in the midrange, and especially hit the converter harder on the upshift, which was what I think was limiting him at the track. Should still carry into the upper 7000's
Feel free to flame away, guys.
Thanks again Darthvader for the time to create this monster.
It's even mentioned in here noting that the mast ls7 heads didn't improve much and intake didn't seem to matter much either.
It's even mentioned in here noting that the mast ls7 heads didn't improve much and intake didn't seem to matter much either.
cam is here, holley terminator x is here. Waiting on my cpe harness to piggyback the stock ecu and Guage cluster.
no rush, car is running still as is though it developed a miss on number 7 cylinder. Codes say injector issue but I tested with a noid light. Nothing showed wrong there.moved injectors around and it does not follow the injector. Either in the driver in ecu or harness has a bad spot that I can't see.
not going to look for the issue, holley and new injectors I have will fix it.
tested coil, plug abs even compression and all are fine.
Cp wire harness has arrived. Dad's in hospital from blood clots shutting off all flow to both legs and I also have a new tractor coming in this week so I wont have a lot of time to do install for a few weeks. I did order sensors also but those already shipped and should have all of them this week. Hopefully cam swap and holley install goes smoothly .
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
Cp wire harness has arrived. Dad's in hospital from blood clots shutting off all flow to both legs and I also have a new tractor coming in this week so I wont have a lot of time to do install for a few weeks. I did order sensors also but those already shipped and should have all of them this week. Hopefully cam swap and holley install goes smoothly .
thank you. He is still in and they are monitoring it close trying to get his legs healed enough so they can do another angiogram on his heart. Looking for blockages there as he has had another mild heart attack after the surgery
Update on all. Car hadn't been touched in a while. Dad did come out of the hospital and after 5 weeks at home,he got an infection that put him back in for another surgery to get that taken care of. That was a Friday, me and my family each got to spend a day with him in the hospital over the weekend and on Monday June 28th,dad went into cardiac Arrest which he didn't recover from. It's been a tough few months but now I'm moving forward with life. I plan to start the swap on the car next week when I get off the boat.
