Bersaglieri

I figured that eveyone would benefit from having a large thread showing the specs of LT1/LT4 camshafts along with recommended power band/rev points for each. I saw this website: http://www.malcams.com/legacy/misc/CamData.htm but I cant help but notice some of its critical information is wrong.

So I thought CamaroZ28.com could show'em how its done. Camshaft experts are welcome to share their knowledge, yes that means you SStrokerAce. Tuners, Madwolf I know you'll love this thread, are welcome to post about tuning issues. If anyone has the exact calculation for lift in respect to rocker ratio, let me know or check these. Any corrections or additions (Like GTP cams) please let me know.

For instance I think the LT4 Hotcam is 218/228 not 226?, and XE230/236 goes higher than 5800rpm for peak performance. Two different type of LT1 camshafts? Isnt it 201/208 .447/.459 w/ 1.5? Not sure on LSA. The stock LT4 cam lifts are .476/.480 with 1.6?

MFG PN DURATION LIFT (1.5) LIFT (1.6) LOBE NOTES
LGM N365 211 220 .492 .492 .525 .525 112 1500-6200
LGM N365S 220 220 .492 .492 .525 .525 112 1800-6400
LGM N385 220 230 .480 .480 .512 .512 110 3000-6500
LGM N385S 220 230 .480 .480 .512 .512 112 3000-6500

COMP 08-304-8 210 220 .500 .510 .533 .544 114
COMP 08-206-8 230 244 .510 .540 .544 .576 114 heads, intake, headers, evhaust
COMP CCA-215-224-14 215 224 .499 .499 .532 .532 114 2200-5700
COMP CCA-220-230-14 220 230 .510 .510 .544 .544 114 2500-6000
COMP/FIS 215 224 .499 .499 .532 .532 112 custom FIS gind blower
COMP extreme CCA-212-218-12 212 218 .488 .495 .521 .528 112 mild
COMP extreme CCA-218-224-12 218 224 .495 .503 .528 .537 112 A4 stk converter
COMP extreme CCA-224-230-12 224 230 .503 .510 .537 .544 112 1900-5600 gears
COMP extreme CCA-230-236-12 230 236 .510 .521 .544 556 112 2200-5800 hvy mods
COMP extreme CCA-236-242-12 236 242 .521 .540 .556 .576 112 2500-6000
COMP extreme CCA-204-218-14 206 218 .480 .495 .512 .528 114 Blower Nitrous
COMP extreme CCA-212-224-14 212 224 .485 .503 .519 .537 114 Blower Nitrous
COMP extreme CCA-218-230-14 218 230 .495 .510 .528 .544 114 Blower Nitrous
COMP extreme CCA-224-236-14 224 236 .503 .521 .537 .556 114 Blower Nitrous
TPIS 700-134 212 236 .483 .520 .515 .555 112 ZZ9 for 93-96
TPIS 700-142 212 226 .483 .520 .515 .555 112 ZZ9 for 95-97
GM .450 .450 .480 .460 93 LT1 STOCK
GM 230 208 .450 .460 .480 .491 116 94-95 LT1 STOCK
GM 205 207 .447 .459 .477 .490 117 96 LT1 STOCK
GM 203 210 .446 .449 .476 .479 115 96 LT4 (STOCK
GMPP 10185071 208 221 .474 .510 .506 .544 112 ZZ3
GMPP 24502586 218 226 .492 .492 .525 .525 112 LT4 HOT
GMPP (Crane) 12370845 214 224 .488 .509 .521 .543 112
GMPP (Crane) 12370846 222 230 .509 .528 .543 .563 112
GMPP (Crane) 12370847 232 242 .539 .558 .575 .595 112
GMPP (Crane) 12370847 232 242 .539 .558 .575 .595 112
Crane 19HR0064 198 206 .480 .480 .512 .512 112
Crane 104124 214 220 .452 .465 .481 .496 112 2000-5500
Crane 104121 204 214 .429 .452 .458 .482 116
Crane 104125 208 214 .438 .452 .467 .482 112
Crane 109621 214 222 .489 .509 .520 .542 112
Crane 104141 218 218 .498 .498 .531 .531 116
Crane 10HR00013 214 222 .488 .509 .520 .543 112
Crane 10HR00017 214 218 .488 .498 .520 .531 114
Crane FIS 215 224 .499 .499 .532 .532 112 Custom blower grind
Crower LM-00402 219 227 .498 .518 .531 .553 108
DRM 222 230 .508 .528 .542 .563 108
Lingenfelter 74211 211 219 .499 .525 .530 .560 112 1600-5200
Lingenfelter 74216 213 219 .462 .471 .493 .502 112 1600-5200
Lingenfelter 74219 219 219 .525 .525 .560 .560 112 1600-6200
Lunati 50160 312-218 .446 .468 .475 .499 110 1500-5300
Lunati 50155 215 218 .489 .503 .522 .537 113 1500-5500
Lunati 50156 232 242 .510 525 .544 .560 108 2000-6500
Lunati 50162 242 252 .525 .540 .560 .576 108 2200-6800
MTI 210 220 .500 .510 .533 .544 114
MTI 230 244 .510 .540 .544 .576 112




General Information for Cam Selection
DURATION:

Duration is the time the valve is open, and is measured in crankshaft degrees. The duration can (and usually is) different between the intake and the exhaust, with the exhaust being open longer (more duration).
More duration will move your powerband up. For instead, a 195 dgr duration cam may have a power peak at 4500 rpm, where a 250 dgr cam may have a power peak of 6500 rpm (number grabbed out of the air, but should give a sense of the numbers). Look for duration measured at 0.050 lift. That will give you a truer idea of the cam. There's also 'advertised duration', recognized by the very large numbers. You should concentrate on the dur@050 numbers. When a cam is said to be a '205 dgr cam' it usually means 205 degrees @ 050 intake duration. Exhaust may be more duration. This is because the intake duration is more critical for how the motor will run than the exhaust duration.
Stock for the LT1 is in the 201-205 range intake (different for different years). A stock car has a power peak at 5000rpm. But other breathing mods such as porting the heads can move the peak up even though the cam remains unchanged.Increasing duration usually increases peak hp, but decreases low end torque. It also increases overlap (see the overlap section below).
LIFT:

The maximum amount (in inches) the valves open. May (and often is) different between intake and exhaust. Lift is generally a Good Thing. More lift makes more torque and horsepower. What limits valvelift is physical contact between valves and pistons or contact between retainer and valveguide. With non-roller camshafts (all LT1s have roller cams), high lift was difficult. this is less of an issue with our roller cams.
When increasing valvelift, the valvesprings have to be checked to make sure they can take the additional lift without binding. Stock lift is around 0.459" on the exhaust valve. Stock LT1 springs get marginal around 0.490". Most aftermarket cams will put you in the 0.520-0.535 range, and you have to get better springs.
Only drawback to lift is that it tends to make a torque curve peaky, i.e. increase midrange while hurting upper and low rpm. This doesn't seem to be too much of a problem on the LT1, though. Even with very high valvelifts, the torque curve stays remarkably flat.
LOBE SEPARATION

Lobe separation is the number of degrees the intake and exhaust lobes are separated. More separation decreases overlap (see overlap below). However, tighter lobe separation makes more high-end hp.
LOBE CENTERLINE:

The relation between the camshaft and the crankshaft. Nearly all street cams like to be 4 degrees advanced.
OVERLAP:

This is the killer for street engines. Overlap is the amount of degrees that the intake and exhaust valves are open at the same time. Unburned air/fuel mixture will be pushed through the cylinder when both valves are open and straight out the exhaust. This decreases mileage, increases emissions, and make the engine run rough at low rpms. It also decreases low-rpm torque, and hurts throttle response.
All cams have some amount of overlap. Stock cams all try to keep the overlap low for the above reasons.
More duration with no other changes will increase overlap. One way of lowering overlap after it's been increased by more duration is to increase lobe separation. This is because moving the lobes away from each other decreases the time they are open simultaneously.

CAMSHAFT CHARACTERISTICS

Range Selection, can someone review this on the site?

Well there is the most I could fit without it looking messed up Perhaps someone would like to link this to their site after revisions have been made *cough* Shoebox

Just trying to help everyone out.

My additions:

TPIS ZZ-409 - 226/226 .520/.520 112LSA [PN for 1993-94 700-120/95+ 700-122]
TPIS ZZ-9X - 225/240 .525/.558 112LSA [PN for 1993-94 700-118/95+ 700-117]
TPIS ZZ-X - 239/239 .558/.558 112LSA [PN for 93-94 700-125/95+ 700-143]

-Dustin-

OldSStroker

What am I bid for the real specs on LE1,2 &3 cams?

Bidding starts with a case (at least) of Pappy VanWinkle 20 year Reserve Bourbon.

Actually only Duke knows, and he's not telling. Shoot, I heard even the Okuma cam grinder operators @ Comp are sworn to secrecy on these.

SStrokerAce

Still not talkin....

And hell there are LE1, LE2, LE3 cams for 350/355's, 383's, 396's. On top of that you have two blower grinds, some n2o cams and the emissions cams in his lineup.

hammrman31, as he said the case of Pappy STARTS the bidding and that's about $1K for a case. That still wouldn't cover it in terms of a bribe but it might get the old man loaded enough to let something slip, but then again I don't even know if he knows all the recent specs!

I will come on later and get more into the characteristics and what the specs do.

Bret

Bersaglieri

Haha, aw man, family feud time. I dont need the specs on LE1,2,3 cams. I think its perfectly ok to keep specs like that a secret, and if you want to know what they are go buy one or marry into Brets family.

I wont be buying one of the cams listed here, I'll be calling Bret as soon as I get my converter in to get the best cam for my application. This list is just to help those who want accurate informationn on LT1/LT4 off the self cams.

I have always wondered different cam's power ranges and recommended rev-to rpm's. I think it would help alot of people from over-camming their 350's.

Thanks for showing up Bret. I figured this would be a great place for you to explain alot of terms, myths, and such for camshafts. I know Lloyd told me there are different flavors of each LE1,2,3 camshaft. So I cam sure there are countless specs to know.

-Dustin-

1-bad-z28

For some reason my hotcam is 219/228. It is not a custom grind.

93LT1355

Really? that's unique, those are the specs of the LS1 hot cam.

1-bad-z28

What lsa is the ls1 hotcam? I will try and post a pic of the cam card that came with the cam.

69gto96z

Would a Lt4 Hotcam give me a noticeable lope in my exhaust note? Also, about how much mileage do you think I would lose in a M6?

1-bad-z28

The lt4 hotcam has a noticable lope especially with a cutout. I am getting around 16 mpg around town (can't stay off the gas) and 27-28 on the highway. That is with a 355 also.

93LT1355

The LS1 and LT1 hot cams both have 112 lsa

SStrokerAce

Let me add some to this....

Ok

Highlight #1. The valve lift has no issue increasing the contact between piston and valve. The exhaust closing event and the intake opening event have everything to do with it.... therefore more duration and smaller LSA's will increase your chances of piston to valve clearance problems.

Highlight#2. More lift does increase peak TQ but it also increases TQ everywhere. More lift helps TQ the higher the RPM since there is less time for filling the cylinders, and lift adds more area for the air to pass thru in the same amount of time.


Yeah in some cases. You don't have to have a cam advanced 4 degrees to make the most power.


Highlights #1 & #2 Overlap is a big limiting factor in street motors, the more you run the less drivable they can be if you don't control some other factors. Overlap itself is not such a low RPM killer as people think, if the rest of your valve events are wrong then it will be.

Highlight #3 Yes lowering the overlap by increasing the duration will help with the ill effects of overlap but it does not help in terms of making power. If you have too much overlap and its causing problems is because you have too much duration also.

Bret

Bersaglieri

Thanks alot for the additions Bret, I guess you really do know what your talking about In case no one knows, Bret is the resident camshaft specialist. If you need a custom one shoot him an email.

Does anyone want to venture into posting their Dyno Graph for any particular cam, or at least know what any single one pulls to? I think knowing how high you want to spin the motor is a big factor in picking a cam, and is sometimes overlooked. If you do post, please list your drivetrain type and modifications. I'd even be happy with some stock cam pulls. Or at least just post what you put down for a particular cam and mods.

-Dustin-

1996LT1NY

Hmmm I have someone around here with a CamDoctor.. supply the cams & the booze & I'll get you the specs...

timelord

I am having rebuild done and know nothing about cams,,,,


Crankshaft=3.875 stroke

Rods= 6 inch

Pistons= Flat top 402gr.

Overbore=.030

Head volume= 58cc Thus 12.0 to 1 compression.

My present cam is LT4 Hot Cam 218-228 ,112 LSA, .525 lift with the 1.6 RR,it will be too mild for the 396.

To run with a nice lope (not 2 violent) similar to my present set up do I need to increase or decrease my LSA.

My LSA should go to 114 then,,

Is 230-240 too violent,

OldSStroker

Are you looking for power and driveability or just a neat sounding lope?

Seriously, if you are looking at changing your cam at all, contact someone who knows a LOT about cams, and have him do your cam. You don't say much about head flow, but that's important for the cam design.

I don't know much about general surgery, so if I needed (or wanted) some, I'd go to a surgeon. I do know a little about camshaft design, but a little knowledge is a very dangerous thing, so I'd go to a cam guy for my cam.

Or, you could always take a poll.

1) more LSA
2) less LSA
3) have a custom cam designed for the engine/vehicle combination

1 vote for 3)

My $.02