Shift points
06-20-2010, 08:42 PM
#1
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Location: Greensburg
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Shift points
So my mechanic ported and polished my stock heads and put 2.02 vaulves in them. he was driving it the other day and he says its wantin to breath more and he wants to change my shift points to 6500. im kinda affraid but he swears up and down my stock bottom end will hold it. what do you think? it already shifts at 5800 right now.
06-22-2010, 11:41 AM
#4
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Location: Hell was full so they sent me to NJ
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There's not much point in raising the shift points with the stock cam. The lift is only 0.450". If he did any sort of decent port work on the heads, they picked up flow in the 0.500 - 0.600" range. A set of 1.6 or 1.7X roller rockers (and required valve train parts) would give you more lift, and take advantage of the increased head flow capabilities. Again, that assumes he knew what he was doing. 2.02" valves are of questionable value, unless he worked the head bowls to unshroud them.
06-22-2010, 02:23 PM
#5
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He did a hell of a job on my heads. he had my valve seats cut and then he went up to the seats with the port. He has about 20 hours in both of them, i know it sounds ridiculous but its true. there is no possible was the port and pollish could get any better. He works for williams percision engins in st. paul IN. www.wpespeedshop.com check it out and tell me what you think. i totaly understand what your saying about the cam and lift. i dnt know much about this kinda stuff so i come to you guys when i question what other people are telling me.
07-04-2010, 02:10 PM
#6
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I disagree with you injuneer on the flow numbers. Since the heads are fully worked up and seems to be done nicely and correctly, your going to see way more increase in flow numbers on the bottom side then you are on the top side of flow numbers with the port work. When you see an increase in the .500 -.600 range your just seeing runner volume size and being a stock head and street car at that, you wouldnt want a very big runner volume. I will agree with the increase in rocker ratio to better benefit from the heads.
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