View Poll Results: What lenght pushrod are you running??
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Poll: What legnth pushrods are you running
01-24-2010, 02:16 PM
#3
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Ill start it off im running a 7.400 PR with LS7 lifters, LS2 trays un-milled 243's and a 232/236 .579/.579 cam. I have slight sewing machine noise.
01-24-2010, 02:57 PM
#5
Your best bet is always going to be to measure.
I did and ordered custom length PR for mine. I'm running 7.475" on the Exhaust side and a 7.500" on the Intake side this gives me a consistant .050" preload on both sides. using my comp cams pushrod length checker I confirmed zero lash on multiple cylinders between both banks then double checked the over all length of the prlc using a large dial indicater which read 7.426E and 7.448I.
TFS235 milled to 64cc, .045" gasket, Morel link bars, 253/261* .646/646" 110LSA
I did and ordered custom length PR for mine. I'm running 7.475" on the Exhaust side and a 7.500" on the Intake side this gives me a consistant .050" preload on both sides. using my comp cams pushrod length checker I confirmed zero lash on multiple cylinders between both banks then double checked the over all length of the prlc using a large dial indicater which read 7.426E and 7.448I.
TFS235 milled to 64cc, .045" gasket, Morel link bars, 253/261* .646/646" 110LSA
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01-24-2010, 05:30 PM
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Similar H/C mods as you, I went with 7.35's and the valvetraine was pretty loud, so I swapped in the stocker 7.4's and it got quieter. I am still not happy with the noise so I am going to check for sure and get the right length
01-24-2010, 07:18 PM
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Curious wht kind of numbers you dyno'd at...
Similar H/C mods as you, I went with 7.35's and the valvetraine was pretty loud, so I swapped in the stocker 7.4's and it got quieter. I am still not happy with the noise so I am going to check for sure and get the right length
Similar H/C mods as you, I went with 7.35's and the valvetraine was pretty loud, so I swapped in the stocker 7.4's and it got quieter. I am still not happy with the noise so I am going to check for sure and get the right length
01-25-2010, 03:58 AM
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Why would you bet that? I said I got a checker and went with the 7.400's. With the checker creating 0 lash the legnth was 7.325 I added .075 preload and that puts me at a 7.400 PR...am I missing somthing???
Last edited by firstinlastout86; 01-25-2010 at 04:07 AM.
01-25-2010, 10:40 AM
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This took 5 seconds of searching to find: from the co-owner of Thunder Racing
With the base circle of that cam, in a stock application (stock block, stock gasket, STOCK head) a 7.425 pushrod will probably give you the optimal preload with those lifters. If any of the factors change, for example, valve job, milling, different gaskets, etc... all bets are off. FWIW I use "LS7" lifters GM PN 12499225for almost all my builds now and check lifter preload everytime. Please be aware, this lifter is the '97 and up replacement lifter for any LS series engine. I also use them in all of my normal LT1 builds.
In cases such as yours, a cam over .600" lift with stock heads 7.425"s seem to work best. You'll end up with approximately .050" preload. You can run 7.4" no problem but you may end up a little noisy. These lifters are very forgiving and will work with a wide range of preload specs. If memory serves, GM calls for .055"-.085" preload. I like to stay on the low end for high RPM apps. Hope this helps...
Shane
In cases such as yours, a cam over .600" lift with stock heads 7.425"s seem to work best. You'll end up with approximately .050" preload. You can run 7.4" no problem but you may end up a little noisy. These lifters are very forgiving and will work with a wide range of preload specs. If memory serves, GM calls for .055"-.085" preload. I like to stay on the low end for high RPM apps. Hope this helps...
Shane
Last edited by 01ssreda4; 01-25-2010 at 10:47 AM.
