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He said it right on post 1, he rolled into the throttle. Looks like around 5k it was picking up steam. The sub 5k numbers frankly don't matter much at all either way, since this is a bonafied 7500-8000rpm racing motor. With a high stall this thing will never see below ~4500.
OP, get some proper valvesprings on this thing and give it hell. I am expecting up to ~575rwhp with no other changes. The cam is not perfect for NA, but we don't know exactly how much you are losing due to valvetrain harmonics up top so no point throwing money at it until you get it right as-is. Bowtienut nailed it on the third reply .
You are literally .001" away from the max lift for those springs(.624 vs .625 max!), and the pressures are too low for even 7k rpm (400# open vs 420# recommended for 7k).
Can't wait to see this motor dialed in, its a monster.
It is common to roll into throttle on big stalled autos to prevent "inaccurate" TQ flash from an unlocked stall. This is what it looks like when you instantly WOT a big stall on a dyno...this WILL blow off the tires on the dyno if you are not careful. Only 400hp down that low but damn near 900ft-lbs registered .
...its not only big power cars too, check out this cute little import with locked vs unlocked stall. Its only a few TQ higher in this case, but on that small of a motor that percentage difference is huge:
You are literally .001" away from the max lift for those springs(.624 vs .625 max!), and the pressures are too low for even 7k rpm (400# open vs 420# recommended for 7k).
He can get that 420lbs or more if he just shims the springs .060" from coilbind. If it's not that tight already, he would see a twofold benefit from the increased spring pressure and from the tighter clearance (better harmonic dampening).
He can get that 420lbs or more if he just shims the springs .060" from coilbind. If it's not that tight already, he would see a twofold benefit from the increased spring pressure and from the tighter clearance (better harmonic dampening).
Shimming the springs is a good idea that I did not think about, but to get to just 420#s he would need a .060" shim which would put him @ 422#s open but also put him .04" from physical coil bind. On a solid roller with massive springs I wouldn't hesitate to run .040 or even .035 coil bind clearance but in this case that is too close for comfort IMO. With his mild spring pressures and aggressive cam I wouldn't trust the valvetrain to keep everything neat and tidy with only .04 clearance between springs...
Also, keep in mind that 420# target is still is likely not enough open pressure for him since that is what COMP recommends for that cam spinning to 7k. If he spins to 7500-8k like his motor will want, he would need higher than that 420#s and he doesn't have the clearance to shim them that much.
The cheapest option would likely be to get the TFS "Option" springs for those heads I listed earlier(TFS-16306-16)...they are ~465#s w/.650" max lift vs his current 400# w/.625" max lift. Note that they are listed at a 1.82" installed height vs 1.8" so if he runs his current keepers and locks there will be an extra ~9#s of pressure.
Shimming the springs is a good idea that I did not think about, but to get to just 420#s he would need a .060" shim which would put him @ 422#s open but also put him .04" from physical coil bind. On a solid roller with massive springs I wouldn't hesitate to run .040 or even .035 coil bind clearance but in this case that is too close for comfort IMO. With his mild spring pressures and aggressive cam I wouldn't trust the valvetrain to keep everything neat and tidy with only .04 clearance between springs...
Also, keep in mind that 420# target is still is likely not enough open pressure for him since that is what COMP recommends for that cam spinning to 7k. If he spins to 7500-8k like his motor will want, he would need higher than that 420#s and he doesn't have the clearance to shim them that much.
The cheapest option would likely be to get the TFS "Option" springs for those heads I listed earlier(TFS-16306-16)...they are ~465#s w/.650" max lift vs his current 400# w/.625" max lift. Note that they are listed at a 1.82" installed height vs 1.8" so if he runs his current keepers and locks there will be an extra ~9#s of pressure.
I ended up installing a set of pac1209x springs today. May be a little more spring than I need for my current cam but I plan on adding 1.8 rockers in the near future and maybe a bigger cam.
I should be able to get it back on the dyno tomorrow. Also I will be running my drag radials instead of the crappy tires I was running last week.
I ended up installing a set of pac1209x springs today. May be a little more spring than I need for my current cam but I plan on adding 1.8 rockers in the near future and maybe a bigger cam.
I should be able to get it back on the dyno tomorrow. Also I will be running my drag radials instead of the crappy tires I was running last week.
Damn man sorry to hear . Was exited to see what it made.
They are pretty much brand new and unmolested so hopefully TFS does right and exchanges the whole head for you...I would tell them you are uncomfortable running them now and push for exchanging both in case it was a bad batch of guides.
Damn man sorry to hear . Was exited to see what it made.
They are pretty much brand new and unmolested so hopefully TFS does right and exchanges the whole head for you...I would tell them you are uncomfortable running them now and push for exchanging both in case it was a bad batch of guides.
Since I am having to deck the heads to get rid of the damage i will need new pushrods anyway and I have a set of comp 1.8 magnum ls3 rockers at the shop i was thinking about running when i get it back together. Now that I have new springs it shouldnt be a problem. I know they are not as good as shaft mounts but i already have them. SHould give me around 660ish lift.
I run a 388” ls3 with mast heads and a mid runner fast. Solid Cam, 246/258 .700 .680 32* overlap, 7/16 pushrods and T&D adjustable shaft 1.7’s. I have a hard time keeping it off the 8000 rpm limiter
I run a 388” ls3 with mast heads and a mid runner fast. Solid Cam, 246/258 .700 .680 32* overlap, 7/16 pushrods and T&D adjustable shaft 1.7’s. I have a hard time keeping it off the 8000 rpm limiter
Very Nice!
Where are you.....in Mexico.....or in the states near the border?
Since I am having to deck the heads to get rid of the damage i will need new pushrods anyway and I have a set of comp 1.8 magnum ls3 rockers at the shop i was thinking about running.........I know they are not as good as shaft mounts but i already have them.......Thoughts?
Run the Ultra Pro-mags.
Steel......solid......but heavy. But the 1209X's should handle them fine.
According to trick flow the ultra pro magnums that i have wont work. Something with alignment i guess. They physically fit and look similar dimensionally to the stock ones. Anyone know why they wouldnt work?
I run a 418 ls3 genx 255heads by tea, jesel pro j2k shaft rockers, manton 5 series push rods, cam motion llsr with pac 1238x springs and i spin it 8200 through the traps.
I run a 418 ls3 genx 255heads by tea, jesel pro j2k shaft rockers, manton 5 series push rods, cam motion llsr with pac 1238x springs and i spin it 8200 through the traps.
Yea on the track LOL, at 2980lbs it goes 9.33@144.8 mph and there is a little more in it. Still need to play with timing, fueling and then the suspension.
03-14-2018, 08:56 AM
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. Was exited to see what it made. 
