Cam experts - need help pls!
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Anyone have an idea of what I can actually fit with my free valve drop measurements?
Here is the setup:
99 Trans Am
221/221 .558/.558 114 cam - needs to go
PRC 220 cc 5.3l stage 2.5 heads - 2.04 intake 1.575 exhaust - I have the PRC double springs (good to .650) (unsure the cc)
GM MLS gasket
7.4" chromemoly pushrods
---Free valve drop .188 Intake .207 Exhaust---(measured with heads bolted on - distance to piston contact including gasket)
Lid and LS6 intake
Pacesetter 1 3/4" headers
3" offroad Y
3" flowmaster catback w/ 3" cutout
!air
!egr
4000 stall 2.4str
3.73 gears (currently 28" tire for approx 3.55 gears)
shift points 6350 - rev limit 6500
I contacted Texas Speed - they said I can fit 228R 228/228 .588/.588
I contacted Futral - they said I can fit F13 230/232 .595/.585 and possibly larger with more measuring
I contacted LG - they said I can fit G5X2 232/240 .595/.608
I contacted Thunder Racing - they said I can fit RapTR 236/242 .615/.615
Anyone have an idea of what I can actually fit with my free valve drop measurements?
TIA,
Aaron
Here is the setup:
99 Trans Am
221/221 .558/.558 114 cam - needs to go
PRC 220 cc 5.3l stage 2.5 heads - 2.04 intake 1.575 exhaust - I have the PRC double springs (good to .650) (unsure the cc)
GM MLS gasket
7.4" chromemoly pushrods
---Free valve drop .188 Intake .207 Exhaust---(measured with heads bolted on - distance to piston contact including gasket)
Lid and LS6 intake
Pacesetter 1 3/4" headers
3" offroad Y
3" flowmaster catback w/ 3" cutout
!air
!egr
4000 stall 2.4str
3.73 gears (currently 28" tire for approx 3.55 gears)
shift points 6350 - rev limit 6500
I contacted Texas Speed - they said I can fit 228R 228/228 .588/.588
I contacted Futral - they said I can fit F13 230/232 .595/.585 and possibly larger with more measuring
I contacted LG - they said I can fit G5X2 232/240 .595/.608
I contacted Thunder Racing - they said I can fit RapTR 236/242 .615/.615
Anyone have an idea of what I can actually fit with my free valve drop measurements?
TIA,
Aaron
Last edited by The Sad; 12-22-2009 at 10:33 AM.
#4
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Is it possible that you are including the head gasket thickness in that free drop dimension. Stock valve free drop is around .150", but if you add a .054" gasket, it's then .204". Your .188" might actually be .134" if you take away the head gasket. That would be normal for a larger valved, smaller chambered head.
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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
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
![](https://ls1tech.com/forums/signaturepics/sigpic210_1.gif)
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
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
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Yes, I was including my gasket in the measurements. I am trying to avoid taking the heads off if I can help it. I suppose that makes sense as to why I keep getting different answers - each shop may be interpreting the numbers differently. Thanks guys.
Patrick, with this knowledge, do you have any thoughts on how big of a cam I could run?
Patrick, with this knowledge, do you have any thoughts on how big of a cam I could run?