Maximum Overlap on F-Body Stock Manifolds
* 02 FBody stock manifolds with SS exhaust or assume a basic catback.
* Medium fast cam lobes such as the Comp XE lobe with ~ .550 lift on small duration cam lobes for the intake, and maybe an XE-R on the exhaust.
Looking at some of the cam results I've seen on the board, it seems that cams with -11 to -13 overlap at .05 seem to be common. I know that some have tried 0 overlap cams with very disappointing results. But what happens inbetween? Say -8 or even -6. I come up with what seem like should be some strong torquey daily driver cams in the -8 or -9 overlap range (e.g 212/222 113, 210/222 112). I've thought about using an XE-R on the exhaust lobe to get a fast lift to reduce overlap at .006 and help out since the XER will open fast on the blowdown.
So the question is at what overlap does power really start to drop off?
I like to decide where I want my motor to make peak power first. 6000 rpm peak, I'll choose a 40 degree IVC. For a 6300 peak, I'll choose more like 45 degree IVC (ABDC at .050"). Next, I decide on the overlap I'm willing to accept. Let's just use -10 for this exercise. Then final item is EVO. I'll choose an earlier opening like 52-53 degrees if it's possibly going to run nitrous and no later than 50 degrees (BBDC at .050") since we still need a fairly early opening for the manifolds. Plug the numbers into your spreadsheet and Walah, you have your cam. This is basically how Thunder Racing came up with the CheaTR cam. The CheaTR is VERY insensitve to back pressure, making it ideal for running pretty much any exhaust out there.

2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
The cheater makes great power, especially on the top end. It is an impressive cam for a stock manifold drag racer as it transforms the power in the 5500 - 6500 rpm in to a car that rivals non-emission compliant cars. The fact that the Cheater spins so high is the early exhaust opening and long duration.
The way I'm looking at it, almost any aftermarket cam makes good power from 3500 - 5500. I'm focused on making better power off the line, from 2000 - 3500 since that is where the car is most of the time driving in an urban environment. I'm willing to give up some of the gain over 5500 and shift at 6000. To that end I've been looking at the stock cams and the valve timing is very conservative.
The stock 02 cam has an IVC of ~34 and the 99 cam is around 38 (IIRC). The Z06 which spins higher is around 42. EVO on all 3 cams is 40 - 44. That Katech 204/218 112 produced a nice graph and closely matched the 02 cam. What I plan to do is keep my valve timing close to stock but increase the duration and overlap. Faster ramps on the exhaust should allow better exhaust flow during blow down without having to open the exhaust much sooner than stock. Here I'm willing to trade HP at 6000 rpm for more torque at 2000 rpm by keeping the valve closed a few degrees longer.
Knowing that I'm safe in the -8 or -9 range will allow the use of one of the above cams which I think would be a good match with 3.73s. If I go to 4.10s, the Cheater or a 214/228 115 would be a good choice as I would not need as much low end and would want a 6300+ shift point.
CheaTR 2 0.006 0.050 0.200
Intake Duration - ID 265 215 141 OMC .600 lift lobe
Exhaust Duration - ED 273 224 146 3722 XE-R lobe
Lobe Center Angle - LSA 114 114 114
Intake Centerline - ICL 110 110 110
Intake Valve opens - IVO 22.5 -2.5 -39.5 BTDC
Intake Valve closes - IVC 62.5 37.5 0.5 ABDC
Exhaust Valve Opens - EVO 74.5 50 11 BBDC
Exhaust Valve Closes - EVC 18.5 -6 -45 ATDC
Exhaust Centerline - ECL 118 118 118
Overlap 41 -8.5 -84.5 degrees

2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
Its like you are "on the cam" as soon as you touch the throttle. I'm adding headers soon and expect to see a decent gain, but won't hold my breath.

2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
intake/exhaust LSA ICL IVC EVO
208 / 220 111 111 35 41
210 / 222 112 112 37 43
212 / 222 113 112 38 45
At the moment I somewhat partial to the second choice, I think the first cam may run out of breath a bit too early although it would be very fun to drive. It looks like it would be similar Nuzees with a little earlier exhaust opening.
I'm not ready to do this yet (unless a cam lands in my lap
) but I will call Thunder to talk about their lobes. I've wondered if the same lobe profile used in their 224 cam could be made available in other sizes. That lobe is fast off the ramp which work well. I'll inquire about the OMC lobe too. Maybe Geoff will be interested in experimenting some more.Comp XE lobes
(6100 rpm shiftpoints, estimate 5800/5850 peak))
0.050
210/224, .556/.568 115+1
IVO>-9
IVC>39
EVO>48
EVC>-4
ECL>116
Overlap>-13
~8.5 DCR with 11.0:1
Stage 1 243 LS2 heads, stock manifolds, 400cfm cats, x pipe, Magnaflow catback, Haltech air intake, ported TB.
03 C5
Target, Stealth ~400rwhp/380+ trq (give or take a few)
I am using that lobe (214/.600) as the intake lobe of the cam in my truck. I have 35,000 miles on the same set of springs and I daily drive this thing. No problem here with beating up the valvesprings.
214-222 559-566 115+4
I'm running it threw shorties and stock cats...
FWIW it idles like stock and makes great power threw the whole rpm band

2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
If you remember in my previous thread you were pushing 42 IVC, with the reason that I will be missing 10 rwhp if i didn't use that.
Yet here, you recommend a 38 IVC.
What is your philosophy behind this? Is it because you are choosing XE-R over XE lobes?
I'm just trying to understand your logic.






