Least LSA before PTV clearance issues.
05-18-2006, 06:15 AM
#1
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Least LSA before PTV clearance issues. What’s the least LSA anybody has run with stock heads and short block before facing ptv clearance issues. I want to get a cam with 108-110 LSA and with 2-4 degree advance on the stock heads and short block that I have.
05-18-2006, 06:51 AM
#2
P to V clearance issues come more from duration than they do from LSA alone. You could run a 224/228 105LSA cam and have no issue, but you might with a 245/255 116LSA cam. You will get intake valve contact at a specific opening or closing degree number. Same with exhaust. Once you know that number, you can back into the narrow LSA cam you want without worry of valve clearance issues.
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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.
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.
05-18-2006, 06:55 AM
#3
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well I am running a 232/240 .579/.579 110LSA with stage 2 heads (2.02/1.57 valves) and have no PTV issues and I did not flycut, BUT I live on the edge.
with stock heads you should be ok as long as the duration is not too big
with stock heads you should be ok as long as the duration is not too big
05-18-2006, 06:59 AM
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I only had .042" Intake clearance with a 224/224 .568" on a 110 LSA +4 (HEADS MILLED .030). So even with stock heads you would be borderline on what seemed like a mild cam! Checked with dial indicator/checker spring/and with my 55 year old mechanic/racer/engineer.
05-18-2006, 07:02 AM
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depends on your duration and how agressive the lobes are.
going 108+2 will be really snug on the intake side. 108+4...I doubt that'll happen at 22x or bigger
going 108+2 will be really snug on the intake side. 108+4...I doubt that'll happen at 22x or bigger
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05-18-2006, 02:17 PM
#8
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Yeah I know the best way is to measure, but at $400 a trial....I thought I could benefit from other people exprience on this. I would want to run in the mid 23x, and don't want to loose DCR with the stock chambers that's why I want to run a tight LSA that should help the heads breath and lower ICL.
