I went to my mechanic on thursday after I detected a bit of noise in the valvetrain (which is usually pretty quiet) from the driver's side. I figured I needed to have my valves readjusted. So I asked him how he goes about it and he said he just does it the way he would with any 350 and goes 1/2 turn past zero lash. Now I remembered reading many threads about adjusting valve lash and it seems that the conclusion is that with comp R lifters you shouldn't go much past 1/16th past zero. The thing is, this is the mechanic who did my cam swap and when he set the valve lash at that time, it was probrbly 1/2 turn past and my car has been running fine that way for 2 years and 3500 miles now (with quite a few trips to the track and dyno), so I didn't say anything to him.

Do you think I should have the valves readjusted? My car has always seemed like it was maybe lacking a bit of power, maybe this has somehting to do with it? Also, do you think I could have damaged a pushrod or lifter by lashing the valves too tight? Thanks in advance.

 

There is tons of discussion on this out there. But it's and easy answer
so here you go.

maximum is 1/8 turn with 7/16 studs with 1/16 or 1/32 preferred

I've run 1/8 with no problem but went back and readjusted to 1/32
last time I did it.

 

If you have been running for 2 years like that, obviously there doesn't seem to be a problem other than that you might gain a little power by lessening the preload.

 

I've adjusted them at 1/2 turn on a friend of mine's car and it did remarkably well and has ran w/out incident.
I know the default answer is 1/16th turn, but you should also keep in mind what thread count your studs are to determine what rate of clearence they have.
I have a 24 count on the studs I'm using. CC suggests .004-.006 preload. For me that would be between 1/16 and 1/8th turn past zero lash. If you want to follow the above preload then try to find out what type of studs you are using and calculate how much you should turn them past zero lash to achieve the clearence listed above. As shoebox said, loose is fast.

 

Alright thanks guys, I'm using 7/16" rocker arm studs so I will probably have them re-adjusted to 1/16th turn past. I will post back to report any difference in power or performance.