Valve size and a stock short block
11-20-2009, 09:10 AM
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Valve size and a stock short block I have been looking around for another set of heads. It seems like there is alot of good deals for ported heads in the classifieds. What is the largest valve size you can run with a stock short block?
11-20-2009, 11:58 AM
#2
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It is not a matter of valve size but what are your goals and cam used? Bigger valves reduce PTV clearance so that has to be factored in.
On stock bore chambers I would not go above 2.055 intake.
On stock bore chambers I would not go above 2.055 intake.
11-20-2009, 04:52 PM
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I was told that you had to use nothing bigger 2.00 valve. It just seems small. What is the largest lift cam that can be used that will clear the pistons without fly cutting? I know that the heads will effect this. Lets just say a standard head that isnt milled way down.
11-21-2009, 01:54 AM
#4
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Clearances are not relative to .050 lift but on durations and valve events and lobe profile used. Max lift occurs near BDC while valve contact occurs near TDC, 2 worlds appart.
take a 2.02 Vs a 2.00 valve the difference in flow at .600 lift would be like 5>10 cfm max (more to the 5 side).
As I said, it is all relevant to cam size and the sum of all parts, you cannot generalise it as a rule of thumb.
take a 2.02 Vs a 2.00 valve the difference in flow at .600 lift would be like 5>10 cfm max (more to the 5 side).
As I said, it is all relevant to cam size and the sum of all parts, you cannot generalise it as a rule of thumb.
