breaking of rocker studs? whoever told you that is full of $hit.

The only downside to running a lot of pressure is wear/tear on rockers and lifters.


Back to the orig post, I would run NO LESS than 200 on the seat with new springs. they will drop quite a bit with some miles on them

 

Yep exactly Jordon.
I used 943s on my setup, 24x dur and 58x lift.

 

I'm hoping you're running a stud girdle.....If not I can see where you info came from, their will be valve train flex with elevated open spring pressures and stud breakage or even pulling the stud out of the head is possible without use of a girdle and or shaft setup.......

 

A cam with less than .600 lift does not require 200-plus lbs of seat pressure. Not when 160-180 is more than adequate, which it probably is in the original poster's case. I would aim for after-cycling pressures of 180 seat, 500 open. The heavier the valve/spring/retainer setup, the more spring required and vice-versa.

My 408 sbc has survived for a few years of street driving with spring setups of 225/650. To give you an idea, the cam is 262/268 .678/.664.

Mike

 

So how about in my case?? I am running a 247/252 .640 lift solid roller. The spring pressures were set up at 180 seat pounds. Should I go up ? Also to answer your question... No I am not running a stud girdle. That is what the guy told me that suggested staying on 180pounds....

 

180-200 on the seat is feasible for a street/strip setup...I think your fine ...your only concern is how high your turning the motor you need enough open pressure to control valvetrain harmonics...I'm figuring your opening pressure with that light on the seat is roughly 450 range.... as I said depending on how high your spinning it determines how much seat/open pressure you need...My guess if you had a spring in the 220 range on the seat and 500-550 open youd most likely make more power in the upper rpms.. there again if going that route i suggest a stud girdle.... the way you have it now will live ,your just giving up some power in the upper rpm...
As far as drag,spring pressures have no affect on perfomance as far as "drag" is concerned since exaust closing and intake opening and vic versa counteract one another equating to (0) loss if anything higher spring pressure will net a gain..

 

I agree with the 180-200 target. If you will set everything up at 200, you should be fine.
Good springs in the 190 lb range should have an open pressure of 525 lbs or there abouts. Using standard performance type valves and titanium retainers, I haven't seen much float turning the engines up to 7000 RPM with this type of spring setup. We use PSI, Manley and Isky springs.

Mike

 

I run the comp 943's on mine also! with a hydraulic lifter"Comp R's" seems to work very well 9.36 @149 Also using an AFR rev kit.

 

So are you running a stud Girdle??



Thanks for all of the info guys.

 

SilverZ28,,

you should be using a stud girdle. tying the studs together strengthens the whole system. if you can afford a shaft setup, then do that and you'd be better off. if not, use the girdle.

JB

 

Ok stupid question coming...

Can i run a shaft mount rocker system with stock plastic valve covers


Do you have a certain part # for these rockers?

 

As already mentioned, shaftmounts are a better setup than a girdle. The problem with a girdle is the hassle....the hassle of having to get tall valvecovers, modifying them for the LT1 alternator mount/location, grinding the girdle itself for the alt/valvecover interference problem, then the hassle of setting lash on #7 and 8 cylinders with already no clearance (tall valvecovers and higher stud girdle just make it worse). They are a nice setup, and strong; however after buying all of that stuff and the modifications and time/fabrication to make it fit, it would just be easier to shell out a little more and get shaftmounts.

Shaftmounts can be run under the stock valvecovers, but modification to the cover or a spacer is necessary.

Shaftmounts also reduce the frequency of having to set lash. With my studgirdle setup, the lash needed to be checked/set every ~4000 miles or so.....it would be a little loose at that point. Guys are going 10k miles with shaftmounts and the lash is dead on. Pretty impressive. I have now switched to shaftmounts.

Jason

 

Oh and FWIW if you look into shaftmounts i would skip over the cheaper Jesel Sportsman Series. I had many problems and ended up not being able to use them (Hey i finally get to use the death smiley!)

 

Thats what I forgot to type Yeah, as Ken said....skip the Jesel S/S shaftmounts.....the have an attractive price, but it ends there. They dont fit correctly.

Jason

 

horsepower takes precedence over "hassle" right guys?

browsing through this forum the other day i saw a link to a guy who is using jesels with the centerbolt covers. looks like he removed the supports and used 1/4-20 studs in the head.

some guys are die hard jesel fans but in my opinion and having used both, if you have the money and want the best, go with a shaft setup from t&d machine.

JB