Head flow with new valves (LT1)..
Thread Starter
Le Mans Master
Joined: Sep 2001
Posts: 7,928
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From: More cowbell...
St. Jude Donor '04
Head flow with new valves (LT1)..
A buddy of mine has a set of LT1 heads, which were ported and tested a couple years ago. With the stock valves (1.94"/1.5") he was flowing 252.1 at 0.600" lift for intake, and 182.2 at .600" for exhaust. He has the car torn appart for a head gasket change, and is thinking about taking it in to get larger valves put in (2.02/1.60).. Any ideas on what these heads may flow with just the larger valves? How much do the larger valves affect the flow?
-Mark
-Mark
Le Mans Master
Joined: Oct 1999
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From: Sachse Texas
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Re: Head flow with new valves (LT1).. (MarkLT1)
I have heard that the LT1 heads work best with the 2.0/1.56 valves and that those are the largest the stock seats can handle. You can go bigger if you swap seats, but you run into valve shrowding problems. I am running 2.0/1.56 myself.
Team Owner
Joined: Nov 1999
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From: Former NCM Drag Racing coordinator, National director Corvette Challenge Spring Hill, Tennessee: Whiting, New Jersey
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Re: Head flow with new valves (STL94LT1)
I am running 2.0/1.56 myself.
Same here.
Same here.
Le Mans Master
Joined: Jul 2000
Posts: 5,012
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From: OKC OK
Re: Head flow with new valves (MarkLT1)
I have some stock LT4 valves that I might be willing to sell. If your interested, e-mail me at vettesterx@aol.com. They are:
Intake: 2.00" (50.8mm) Hollow stem, Weight: 85 grams, 3.00 ounces
Exhaust: 1.55" (39.4mm) Sodium filled stem, Weight:75 grams, 2.65 ounces
I wouldn't go with a 2.02 intake unless you get the seats cut.
[Modified by LT4POWR, 9:15 AM 5/9/2003]
Intake: 2.00" (50.8mm) Hollow stem, Weight: 85 grams, 3.00 ounces
Exhaust: 1.55" (39.4mm) Sodium filled stem, Weight:75 grams, 2.65 ounces
I wouldn't go with a 2.02 intake unless you get the seats cut.
[Modified by LT4POWR, 9:15 AM 5/9/2003]
Melting Slicks
Joined: Mar 2003
Posts: 2,472
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From: Toronto ONTARIO
Re: Head flow with new valves (LT4POWR)
see that recent engine masters challenge in hot rod magazine. they found that a much larger valve doesnt really hinder velocity as much as previously thought. My shoppe tuner always said the same thing. I went with a 2.08 valve in my LT4 heads and they flow 299 cfm @ .550 and 313 @ .600 lifts. He also does tune racecar engines so im convinced he knows what hes talking about.
Id also suggest a 2 inch valve. Look into the LT4 valves.... theyre awesome and VERY expensive if bought from GM. The intakes are hollow and the exhausts are sodium filled to help dississipate heat better. Only issue is that they are fatter than an aftermarket valve.. which may cost some flow on a serious race motor. :cheers:
Id also suggest a 2 inch valve. Look into the LT4 valves.... theyre awesome and VERY expensive if bought from GM. The intakes are hollow and the exhausts are sodium filled to help dississipate heat better. Only issue is that they are fatter than an aftermarket valve.. which may cost some flow on a serious race motor. :cheers:
