Questions on a 94 305 TBI V8
 

Here my friend and I were thinking we could just buy parts and bolt them on! :banghead: He's bought a new cam, lifters, and timing gears so far for the motor, and will soon get pushrods, roller tip rockers, Z-28 valve springs, retainers, valve seals, and retainer locks for it as well. Unfortunately we're unsure of some stuff. Here goes the list. For a stock 94 305 TBI:

-What is the stud size for the rockers?
-What is the valve stem diameter? (for the valve seals)
-When you use roller tip rockers, do you have to machine the rocker stud boss (or whatever you call it), and use guideplates, or would it just be better to run stamped steel rockers?
-What is the installed height for the valve springs on this motor?

I can't seem to find most of this info, and I think I asked a question or two before, but its easier to get it all together at once. Also, if you have any more advice or words of wisdom, please let us know. I really don't feel like accidently destroying his truck. :D :crazy:

to the top for the people just getting out of work

You have to run special rockers on those later model heads. They are known as self guided or self centering rocker arms. They are available in roller, just a little harder to find. They changed when they went to the center bolt valve cover heads.

I did find some self-aligning roller tip rockers, sucks that they are almost twice as expensive, but at least its not my money! :D Does that mean that guide plates aren't needed then?

No guide plates needed. Those rocker arms align themselves with the valve tips.

What about the pushrods then? What keeps them from flopping around? (I don't have the engine apart in front of me and can't visualize what would hold them still).

They're captured by the divot in the rocker arm on top and the lifter on bottom. The rocker arm indexes off of the valve tip.

Maybe I'm not thinking of this right. Which side is the roller tip on, the valve tip or the pushrod end? I thought it was the pushrod end, which would only leave a smooth surface for the pushrod tip.

*EDIT - Man I'm dumb! Simple geometry says that the longer end (the one with the roller tip) should be on the valve side to give a 1.5 ratio, otherwise it would be a 0.66 ratio! :rolleyes: :banghead: :banghead: :banghead: :crazy:

no, it's the valve tip side of the rocker arm that has the roller. The roller has a little nib on each side of it to keep the roller centered over the valve tip. The roller is meant to roll over the valve tip rather than slide like the stockers do.

The other side of the rocker arm has a recessed divot in it that the pushrod seats into.

On a side note, famous engine builder and Chevrolet guru John Lingenfelter did some experiments years ago and determined that the rollers don't actually roll in use. He found that the spring pressure overcame the ability of the roller to roll and caused it to simply slide. Basically, he said to spend your money on something else in search of horsepower. I'm quoting this from Lingenfelter's Small block Chevy book.

Here are some that arent too high priced and imo a decent rocker

http://www.jegs.com//cgi-bin/ncommer...75&prmenbr=361