Max effort LS7 Cam suggestions needed
07-15-2013, 09:57 PM
#61
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I like the lifter set up though I don't need it, is superior and I must add getting away from link bars save a lot of weight, complication and valve springs harassment.
What wall thickness are you using with the 7/16 push rods and are you using restrictor holes?
What wall thickness are you using with the 7/16 push rods and are you using restrictor holes?
07-16-2013, 12:46 AM
#62
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My pushrods are made by TREND. They are 0.125" wall thickness. No they do not have restrictors. I am using JESEL rocker arms:
Also, we had to machine a notch in the JESEL rocker arm stand at each intake pushrod for clearance. Note the notch in the stand just above the black ARP bolt head:
With 0.750" of lift at the valve the entire system works flawlessly.
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07-17-2013, 11:30 PM
#63
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Awesome set up no way to have problems when you have the rite parts, is the way to have fun, I'm using TD machine rockers version and 3/8 .082 wall Manton push rods on my mild street motor solid lifter cam and love it, I like to spend the money once and do it rite have fun no worries, congrats Pumba.
07-18-2013, 07:48 AM
#64
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Awesome set up. No way to have problems when you have the right parts. It's the way to have fun. I'm using TD Machine's version of the rockers, and 3/8 x .082" wall Manton push rods on my solid-lifter cammed, mild street motor, and love it.
I like to spend the money once and do it right, have fun, and no worries.
Congrats Pumba.
I like to spend the money once and do it right, have fun, and no worries.
Congrats Pumba.
Thanks for the generous comments. Enjoy you car!
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10-04-2013, 11:11 AM
#66
Typical Intake Valve Close point for a LS7 427 with 270-280cc port volume and a 2.200" valve will be around 50-52 degrees ABDC. That means the piston is almost 1/3 of the way back up the bore on the compression stroke before the cam is at .050" lift, which is .090" at the valve. The same engine using 245cc cathedral port heads with 2.10" intake valves may stand a IVC of 54-56 degrees ABDC, and with 305cc heads using 2.250" valves it may want a IVC of 47-49 degrees.
The smaller the port volume and valve diameters are, the longer the port will exhibit forward flow during the intake cycle (compression stroke), and vice versa. Larger ports and valves will exhibit less velocity, so therefore the forward flow of air will stop sooner in the cycle, which requires closing the intake valve sooner as to not loose too much average power.
It's difficult to gain top end power using larger heads on a engine when using a long runner EFI intake like the stock LS7 or Fast, but it's very easy to lose low end torque as the heads get larger.
If larger heads were the key to making more power, then all LS3 and LS7 heads would make more power than all of the cathedral port heads. But when you look at back to back head testing like the Hot Rod cathedral port head shootout, you see the largest heads did not make the most power.
The smaller the port volume and valve diameters are, the longer the port will exhibit forward flow during the intake cycle (compression stroke), and vice versa. Larger ports and valves will exhibit less velocity, so therefore the forward flow of air will stop sooner in the cycle, which requires closing the intake valve sooner as to not loose too much average power.
It's difficult to gain top end power using larger heads on a engine when using a long runner EFI intake like the stock LS7 or Fast, but it's very easy to lose low end torque as the heads get larger.
If larger heads were the key to making more power, then all LS3 and LS7 heads would make more power than all of the cathedral port heads. But when you look at back to back head testing like the Hot Rod cathedral port head shootout, you see the largest heads did not make the most power.
10-04-2013, 04:34 PM
#68
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I just did a BTR St4 cam which has a 52IVC point with only the following mods:
ARH 1-7/8 with ORX
Stock axle back mufflers w/ flaps open
BTR St4 Cam
Ferrea Stainless exhaust valves (just dropped in, no cylinder head work period)
BTR Platium Spring Kit
Everything else was left bone stock, air intake, filter and all.
On my Dyno Dynamics it made 507.8rwhp and peaked at 68-6900 and carried it. I'll get a graph later on to see.
Sounds like a low dyno number but the fastest NA C6Z with H/C/I setup only made 519rwhp here and went 141mph. So that tells me the WCCH st2 port job on heads and the port matched FAST102 intake did little to nothing for these SBE combos.
ARH 1-7/8 with ORX
Stock axle back mufflers w/ flaps open
BTR St4 Cam
Ferrea Stainless exhaust valves (just dropped in, no cylinder head work period)
BTR Platium Spring Kit
Everything else was left bone stock, air intake, filter and all.
On my Dyno Dynamics it made 507.8rwhp and peaked at 68-6900 and carried it. I'll get a graph later on to see.
Sounds like a low dyno number but the fastest NA C6Z with H/C/I setup only made 519rwhp here and went 141mph. So that tells me the WCCH st2 port job on heads and the port matched FAST102 intake did little to nothing for these SBE combos.
10-08-2013, 10:39 AM
#69
I'll try and get some graphs from a customer with a 68 camaro that has a LS7 engine in it as well to toss my contribution into the thread.
We started with a LS7 Polluter cam, which is similar to Brian's Stage 4, but has less intake duration and slightly less overlap. Polluter cam has a 49 IVC event. Peaks at 6400, carries to 7000rpm easily.
With milled LS7 heads and 12:1 it made 582rwhp.
We went to an even larger custom cam, of 250/262 111lsa with an IVC event of 52 and 36 degrees of overlap and it picked up 22rwhp and 24rwtq.
Same car went 150mph in the standing half mile. Other H/C/I LS7 C6's at the same event were going 152-153 with 40 years of wind tunnel testing, 40 years of aerodynamics advancements and much lighter curb weights.
I'd say that's pretty good.
We started with a LS7 Polluter cam, which is similar to Brian's Stage 4, but has less intake duration and slightly less overlap. Polluter cam has a 49 IVC event. Peaks at 6400, carries to 7000rpm easily.
With milled LS7 heads and 12:1 it made 582rwhp.
We went to an even larger custom cam, of 250/262 111lsa with an IVC event of 52 and 36 degrees of overlap and it picked up 22rwhp and 24rwtq.
Same car went 150mph in the standing half mile. Other H/C/I LS7 C6's at the same event were going 152-153 with 40 years of wind tunnel testing, 40 years of aerodynamics advancements and much lighter curb weights.
I'd say that's pretty good.
10-09-2013, 09:55 AM
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Hey guys, since there are what seems to be very knowledgeable fellas in here, could some of y'all answer something...over on CF there has been a lot of guide issues , rocker arm ratio issue and valve issues. Guys always post "ohh you should've got MAST heads or BRODIX or any other really reputable brand set of heads. What difference would that make with the more expensive quality heads versus OEM LS7 heads in terms of reliability. Isn't it all in the machining for the new guides and which setup you choose? And then whatever you choose whether it be machined OEM or MAST Black Label, both would be just as realiable or am I missing something besides power that a quality set of heads will give you in terms of reliability?
10-09-2013, 02:55 PM
#71
I believe most guys are saying that because most of those guys are CNC porting their cylinder heads as the same time.
On CF, WCCH is the hot ticket for stock castings, and their port work, guide replacement and new exhaust valves is pretty much the same cost as a nice set of aftermarket heads.
I would imagine this is how they're coming to such a statement or conclusion.
On CF, WCCH is the hot ticket for stock castings, and their port work, guide replacement and new exhaust valves is pretty much the same cost as a nice set of aftermarket heads.
I would imagine this is how they're coming to such a statement or conclusion.
10-16-2013, 08:16 AM
#74
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the most power mast have made NA according to Chris Durrett is 860hp with hilborn injection on inline valve heads.My engine peaked at 7300 with 66 deg @50 IVC, however it is 273@50 in duration being a solid roller with faster ramp rate its equivalent IVC using advertised duration is around the same as a 253 hydro roller (both advertised at 303 duration). looking at it this way the equiv IVC with hydro roller is 56.5 deg at 50 thou lift, the advertised total will change the peak, more importantly the cross sectional area and manifold taper will change where the port chokes at mach .55. I found the bigger 305 mast heads love a lot more cam, in order to make them work up where they should be, need the duration to keep up.If the engine is peaking short of what the cyl head(using csa formulas) should be peaking on the given ci, then the lobe centres need to be spread and intake duration increased. If engine peaks at say 7000 rpm, and cyl heads are meant to peak at 8200 rpm, (assuming u have adequate compression and valve stability) then the lobe centres are widened chase a later IVC with more total duration and more exhaust duration. This has been proven over and over again by the best engine builders on planet, and I have found it to be true myself. Look at some of Joe Shermans buildups he shows plenty of examples.
Look at some of Joe Shermans buildups he shows plenty of examples.
10-16-2013, 10:22 AM
#75
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Guys, I see the "ARH" coming up quite a bit in this thread, Thanks very much for choosing us as the header for these builds.
We work closely with many of the LSx shops through out the U.S. to achieve results.
Brian Tooley is pretty high up on the food chain when it comes to cylinder head/cam shaft work/selection. I'd invest in a phone call to Brian.
If you need ARHeaders please give us a call at the shop or better yet, BTR is also an ARH dealer.
Steve
We work closely with many of the LSx shops through out the U.S. to achieve results.
Brian Tooley is pretty high up on the food chain when it comes to cylinder head/cam shaft work/selection. I'd invest in a phone call to Brian.
If you need ARHeaders please give us a call at the shop or better yet, BTR is also an ARH dealer.
Steve
10-19-2013, 01:34 PM
#77
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Steve,
We order all of our Headers in through Brian and want to thank you for the quality work you guys put into your products! In my experience with all the dyno tuning the ARH headers perform all the time!
We order all of our Headers in through Brian and want to thank you for the quality work you guys put into your products! In my experience with all the dyno tuning the ARH headers perform all the time!
12-19-2013, 07:53 PM
#78
12-23-2013, 07:51 PM
#80
That Vette that runs 9.86@141 on motor is just pure nasty ... part of the reason I'm demodding and selling my speed parts,putting my GTO back stock and then selling it too.
Stock bottom end C6 Z06(other than pistons for nitrous),worked over production heads,cam,exhaust,FAST intake and he's flyin' !!
Would there be an advantage to using the RHS Pro Elite raised runner LS7 head with a custom ground cam or are they more suited for use with a 4 barrel style intake/tunnel ram intake and not the F.A.S.T./OEM style intake manifolds? Supposed to work with OEM or F.A.S.T. intakes.
Stock bottom end C6 Z06(other than pistons for nitrous),worked over production heads,cam,exhaust,FAST intake and he's flyin' !!
Would there be an advantage to using the RHS Pro Elite raised runner LS7 head with a custom ground cam or are they more suited for use with a 4 barrel style intake/tunnel ram intake and not the F.A.S.T./OEM style intake manifolds? Supposed to work with OEM or F.A.S.T. intakes.
Last edited by weldermike27408; 12-23-2013 at 08:14 PM. Reason: found build info
