brodysZ28

Heres the deal. Bought these pro comp heads (this is what I get) and the rocker tip is not centered on the valves for cylinders 6 and 8. I think it is real messed up and DO NOT think it is good for the motor. I could use adjustable guideplates to get the tips centered but then the rocker would be crooked and the pushrod would be angled. Can I get some opinions of experienced engine builders?

old z mzn

iTrader: (1)

check your push rod holes in the cylinder head for clearance. might need a little enlarging and yes guide plates

brodysZ28

I am using guide plates right now, but to get the tips centered I would have to get adjustables.

Twin_Turbo

iTrader: (25)

Get adjustables only solution here. Getting the roller centered over the valve stem is more important than the pushrod sitting a little crooked. Make sure you have enough pushrod clearance in the head. Willing to bet that if you measure out the head, rocker studs in relation to valves that there's a machining error in them. Hate to say it, but you get what you pay for. Then again, Ive had some edelbrock rpm heads with problems with regard to pushrod clearance so us made is not always issue free (unless those heads are also cast and machined in china, which wouldn't surprise me)

brodysZ28

Okay so first priority is get the roller centered on stem. Now what about using offset rockers for the ones that need them... I hate even talking about bandaid solutions for things like this. The rocker stud is definitely drilled in the wrong spot.

old z mzn

iTrader: (1)

you could use stamp steel rockers

Shadygrady

iTrader: (3)

Had same issue with my zz4 heads which i had machined for guide plates.Isky adjustable guide plates solved the issue.been running for years no issues.

brodysZ28

Well, any solution to this is no doubt a bandaid to a messed up head, so I called the place I got them from and they are going to replace the head for me. I'm going to check the drivers side head closely. I talked to guys from Isky and Comp cams. Quote from comp "I can't tell you are not going to have problems at high rpm's".

So yes guideplates will get the roller centered. But then everything else is not aligned, and depending on the severity of it, the motor will run fine, or wear the valve guides, or bend a pushrod, or spin the rocker, just a lot of bad things that could happen.

Shadygrady

iTrader: (3)

Huh?I remember all looking good but since you brought it up i need to take a look next time my valve covers are off.I did bend a pushrod while breaking a 7/16 inch rocker stud but determined the problem to be too long of a pushrod with a pushrod length checker.i bought the longest studs I could find and bought one thousandth shorter pushrod.That was 5 years or so ago without a repeat but i deffinatly need to check into this.
This makes me wonder if the pushrods being too long threw off the geometry now that ive read this.Ive also wondered how the shorter push rod affected the lift numbers for my cam.something was off to break a 7/16 "stud and bend a pushrod on startup..
Glad they`re gonna replace your heads.I took mine back to machine shop and they double checked them and said they were fine.