LSX Block 427ci, PRC 265cc Ls7 Heads
02-10-2012, 11:38 AM
#21
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Once you go with a th400 your dyno #'s can vary huge. Our real street rhs 461, trickflow 265, solid roller .800 lift, beck intake, 15:1 comp made 861 on the engine dyno and dynoed 590whp. It did run 141 mph on motor though. Once you go with a glide, th350, th400 toss the chassis #'s in the can.
02-10-2012, 01:36 PM
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427 Your dyno #ers certainly wont do that motor justice through that drivetrain. I would guess 660 minimum at the flywheel NA. Thats a pretty good size cam for LS7 heads with that intake. The intake will be your restriction for peak horsepower.
Last edited by dtroike; 02-10-2012 at 02:56 PM.
02-13-2012, 10:45 AM
#26
Also if you have a loose converter that flashes to a pretty substantial rpm off the hit, most dyno's have a hard time being able to keep up with the torque curve/output and the numbers will be skewed.
Pat G does know his stuff, I just think your heads would do better with more exhaust split on a wider lsa.
Pat G does know his stuff, I just think your heads would do better with more exhaust split on a wider lsa.
02-15-2012, 09:25 PM
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Ya Iv herd of big cam spec in LS7 and LS3 headed build and ppl saying how it ran like crap down low so they swapped out cam for a smaller one and it rans just as good but pulled harded down low.....but this may have only been a issue w the newer style PCM and not our 4th gen style
02-16-2012, 07:36 AM
#30
Ya Iv herd of big cam spec in LS7 and LS3 headed build and ppl saying how it ran like crap down low so they swapped out cam for a smaller one and it rans just as good but pulled harded down low.....but this may have only been a issue w the newer style PCM and not our 4th gen style
02-21-2012, 09:23 AM
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Here's a little help...
GMPP LSX block 427ci
Callies 4 inch stroke crank
Howards 1000hp billet rods
Wiesco -2.8 cc pistons
deck height -.003
.036 comedic gasket
Heads are PI/MAST 6bolt angle milled by WCCH to 58cc's (and now 11 degree angle) = 13.6 to 1 compression
Crower Shaft rockers
Cam is a 243/255 113+4 660/670 lift (found out quick that bigger cams don't work that well with a FAST manifold on these combos).
FAST ported and raised to fit the heads by LS2 PORTWORKS
Nick Williams 102mm t-body
ARH 1 7/8 headers, Dual/Dual cat back, 4inch race ready cut out after the cats...
Strange 12 bolt 3.73 gear ratio.
4L80E
Circle D 4C converter... Flash rpm 5400 on the dyno
It made SAE 584, STD 601 (locked). Unlocked SAE 530, 547 STD. I will have to wait to see what the extension is on the track to find if I need to restall. With a little break in time, NO cats and a 4L60E, I might have seen 560 unlocked. So you can see how hard it is to make 580 unlocked with a Fast manifolded combo "with a loose converter"(...54hp is getting up there). I do have video on you tube but I can't get on it for the link from work. If you want to see a few pulls search "Nohorsepower" on youtube...
GMPP LSX block 427ci
Callies 4 inch stroke crank
Howards 1000hp billet rods
Wiesco -2.8 cc pistons
deck height -.003
.036 comedic gasket
Heads are PI/MAST 6bolt angle milled by WCCH to 58cc's (and now 11 degree angle) = 13.6 to 1 compression
Crower Shaft rockers
Cam is a 243/255 113+4 660/670 lift (found out quick that bigger cams don't work that well with a FAST manifold on these combos).
FAST ported and raised to fit the heads by LS2 PORTWORKS
Nick Williams 102mm t-body
ARH 1 7/8 headers, Dual/Dual cat back, 4inch race ready cut out after the cats...
Strange 12 bolt 3.73 gear ratio.
4L80E
Circle D 4C converter... Flash rpm 5400 on the dyno
It made SAE 584, STD 601 (locked). Unlocked SAE 530, 547 STD. I will have to wait to see what the extension is on the track to find if I need to restall. With a little break in time, NO cats and a 4L60E, I might have seen 560 unlocked. So you can see how hard it is to make 580 unlocked with a Fast manifolded combo "with a loose converter"(...54hp is getting up there). I do have video on you tube but I can't get on it for the link from work. If you want to see a few pulls search "Nohorsepower" on youtube...
Last edited by jimbob; 02-21-2012 at 09:39 AM.
