showvette

Aluminum LS1 block has been decked .015". Stock casting 241s were decked .015". New 2.02"-1.60" valves, Cometic .051" head gaskets, COMP XER 281, Scorpion 1.7 roller rockers, COMP 850 lifters, Scorpion 7.400" pushrods, new AC Delco rocker bolts. I'm getting between 1 1/2 - 1 3/4 turn past 0 lash @ 22 foot pounds. According to specs, I'm within the 1 1/4-1 3/4 range. Just curious as to why I'm not needing shorter pushrods???

Frank

vettenuts

iTrader: (4)

Did they re-do the valve seats when they worked on the heads? Are they stock GM valves or aftermarket? If they used aftermarket valves or worked the seats it may change the pushrod requirement.

Also if they did do this, check several pushrods for length, not just #1, just to make sure you get a consistent length.

showvette

They're Ferrea valves. The heads were done by Lloyd Elliot. I'm not sure if he changes the seats. I've done both rods on #1 and #3, with the same results.

showvette

If I understand this correctly, each full turn of the bolt is .047". 1 5/8 turns would equal .076" preload. Will that preload be OK for a cam that makes power to 7200 RPMs?

Frank

JakeFusion

iTrader: (7)

That'd be fine. If you are doing sustained high RPM i'd go with a .025" shorter length to run less preload.

showvette

Actually a show car...LOL It will see the quarter mile a couple times a year, but it's not going to get beat on continuously.

Frank

JakeFusion

iTrader: (7)

Then your preload is good. It'll run quieter.

vettenuts

iTrader: (4)

If he used Ferrea valves, then the stems may be shorter than GM and that may be why you are getting these values. If you have the Ferrea part number and a stock GM valve you could verify it if you wanted to but not necessary other than curiosity.

Finish in the gasket surface looks real nice by the way.