What do you guys think about this cam?
12-29-2011, 07:20 PM
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What do you guys think about this cam?
I have done a bunch of larger motors for lighter cars. I am going to put a Comp 265LR HR12 in my 06 L33 5.3L EXCB Silverado 4WD. I am doing headers and an U/D also. The specs are 215/223 .604/.610 112. Any one running this thing? Says it is good for tq which is what I am looking for. Keeping the stock converter for now. Just want some more bottom end and gears are too expensive.
Last edited by Pray; 12-29-2011 at 08:43 PM.
12-30-2011, 02:15 AM
#5
That L33 should have the 799/243 heads on it, and a 9.9:1 compression ratio if I'm not mistaken. Those heads flow way better than the LM7 heads, and I think the lift that you listed on that cam is not excessive for YOUR application. The shorter duration numbers, with that lift, on the lower LSA should make that cam pretty torquey and responsive. I'd even try it with a PD blower....
12-30-2011, 07:44 AM
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I am going to run Comp 918 springs with TI retainers. They are good for .625 lift and should fit my needs. I wanted to keep the LSA short and the lift in the .600 range to take advantage of the 243 heads and keep the power up in the lower rpm's. The short duration on the intake is perfect in my opinion for the truck but was a little concerned about a 8* split for the exhaust on a N/A motor. I ran the LSL lobes in my Z06 with great results. Small aggressive lobes seem to do the trick. I also think it will be pretty good for a blower. I plan on rebuilding a 5.7L and 4L60E trans that I have laying around with a 2,400 or so stall, and think this cam will fit both combo's. Some AFR 205's and a FAST 102 combo should be good for 400/385rw when I am done. I am not going to be drag racing this thing and it will rarely see over 6,000rpm. I just want a good torquey motor to help it get out of it's own way.
12-30-2011, 11:48 AM
#7
there is no way the stock heads are going to flow well at .610" lift. My ported 317s start to stall around .590". I personally wouldn't go over ~.580" on both sides until there is port work done. while you'll probably see a gain, it will probably be small if noticeable at all. You'll probably benefit more from running lighter springs on a slightly smaller cam. Again, this is all given stock heads. Ported heads changes the game.
As for the lift, intake is in good spot for a stock converter, but the exhaust spread seems a little wide. You'll make good numbers up top, but if you tighten it up a little bit, like a 216/220 .580"/.580" on a 110-112 LSA, you'll see more tq lower in the RPM range. Remember that Back pressure is a great way to build torque. The cam you suggested, combined with LTs doesn't facilitate building back pressure. In fact, its exactly the opposite, it supports getting the gasses out quick, which is whats necessary when you are higher in the rpm band, at WOT. To me, thats a great HP cam for a bolt on motor, not a "get it moving from a light" cam.
Everybody told me that I was nuts for putting a reverse split cam in my 6.0. I don't spend much time between 4 and 6K, but I do like to pull like a raped ape from a light. And thats exactly what it does. You can feel it go a little flat around 5K, but the truck will throw **** from the center console to the back seat from a stand still.
As for the lift, intake is in good spot for a stock converter, but the exhaust spread seems a little wide. You'll make good numbers up top, but if you tighten it up a little bit, like a 216/220 .580"/.580" on a 110-112 LSA, you'll see more tq lower in the RPM range. Remember that Back pressure is a great way to build torque. The cam you suggested, combined with LTs doesn't facilitate building back pressure. In fact, its exactly the opposite, it supports getting the gasses out quick, which is whats necessary when you are higher in the rpm band, at WOT. To me, thats a great HP cam for a bolt on motor, not a "get it moving from a light" cam.
Everybody told me that I was nuts for putting a reverse split cam in my 6.0. I don't spend much time between 4 and 6K, but I do like to pull like a raped ape from a light. And thats exactly what it does. You can feel it go a little flat around 5K, but the truck will throw **** from the center console to the back seat from a stand still.
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12-30-2011, 07:18 PM
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03BLACKOUTSS.
I looks like the stock 243's flatten out around .500 but hold their numbers till after .600 and drop off at .650 from the info I could find. Most cams designed for stock headed Z06's are well over .600 lift with great results. The stock heads on the LM7 motors may. I do tend to agree with you on the duration split being a little large. I like a 4* split on stock Z06 heads. I ran a 224/228 114 and made 415rw with headers only in my Z. I have had good results with single pattern cams in ported heads where the intake/exhaust flow ratio was above 75%. Never messed with a reverse split. I am eventually going to do ported heads or some AFR 205's so this cam is destined for a ported head 346. I will also look into the back pressure thing but never seen a car make more power with less exhaust flow. Then again this is my first small motor that I am going for tq in over power. Thanks for the advice and I will look more into what you said.
I looks like the stock 243's flatten out around .500 but hold their numbers till after .600 and drop off at .650 from the info I could find. Most cams designed for stock headed Z06's are well over .600 lift with great results. The stock heads on the LM7 motors may. I do tend to agree with you on the duration split being a little large. I like a 4* split on stock Z06 heads. I ran a 224/228 114 and made 415rw with headers only in my Z. I have had good results with single pattern cams in ported heads where the intake/exhaust flow ratio was above 75%. Never messed with a reverse split. I am eventually going to do ported heads or some AFR 205's so this cam is destined for a ported head 346. I will also look into the back pressure thing but never seen a car make more power with less exhaust flow. Then again this is my first small motor that I am going for tq in over power. Thanks for the advice and I will look more into what you said.
Last edited by Pray; 12-30-2011 at 07:28 PM.
12-31-2011, 06:27 AM
#9
No worries man, just passing along some info. Thats good to know about the 243, I didn't think they would even hold a constant flow that high. Just remember, cars can play with HP, they are lighter. A ~5500 pound pig needs some serious tq to get moving.
12-31-2011, 07:51 PM
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I hear you on the weight. IFRC I weighed mine at the dump and it came it in the high 4,000's. I am going to have to weigh it again to be sure. I know the L33 saves 100lbs but that is pretty insignificant above 4,000 lbs. I would love to do at least a 383 out of the motor I have laying around but we will see. I looked up three flow charts and all were inbetween 252 and 260cfm from .500 to .600 then back down to -10cfm by .650 on the 243 heads.
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