cruisin72

Converting factory heads to stud style rocker arms. Already have them drilled and tapped for a 7/16 base thread. Would like to stay with a 5/16 pushrod.
All I can find is 7/16 stud hole/3/8 pushrod slot guideplates or small stud hole/5/16 pushrod slot.
Does anyone make a guideplate that can be run with 7/16 stud hole and 5/16 pushrod slot?
I was trying to avoid having to drill the pushrod holes in the heads. I know they get pretty close with a 3/8 pushrod.

Inline

Buy ones with slot for 5/16 pushrods and enlarge the stud holes? Thats what i would do if i was staying 5/16 pushrods and no guideplates for your setup available.

Personal opinion would be of course to open up pushrod tunnels for thicker pushrod, but that really wasnt the question

cruisin72

I attempted drilling some #4842 comp guideplates. They are made of some seriously hard stuff. I imagine I'll just order the edelbrock guideplates and open up the holes in the head.

OLDSter Ralph

The larger diameter pushrods would be more rigid. The guide plates are hardened so that the slots don't wear out. The guide plate holes could be opened up with a carbide end mill or good carbide drill, slow rpm's, a good cutting oil and a rigid machine.
With changing all the valve train stuff, will you need different length pushrods ?

cruisin72

Without a doubt it will take a custom length pushrod. Looks like 8.000 will work good.

RocketV8

I'm using ISKY 200AGP adjustable guide plates on my 330 (7/16" stud holes, 5/16" pushrods). Works great.

http://iskycams.com/shop/index.php?m...&pg=categories

oddball

The Edelbrock plates can be drilled pretty easily. I think I just used a decent quality step drill.
I have ebrock heads on a 403 with a roller cam and 3/8" pushrods. Tried to clearance the bottom of the pushrod holes but apparently didn't do enough. So it's all back apart again to hog them out some more. A few hit *a bunch* so I swapped in 5/16" pushrods on two cylinders in the car.
If I could do it again, and hadn't dumped $$$ on fancy 3/8" pushrods, I'd just stick with 5/16".
Amazingly, the pushrods don't hit the collar on the lifter!

cruisin72

I thought about using the split guideplates, and may still have to go that route.
I clearanced the heads for the 3/8 pushrods, looks like no problems there. Now having major interference issue with the pushrod hitting the backside of the erson rocker arm from mid to peak lift. Even checked it with a 5/16 pushrod and still rubs, though not nearly as bad.
What brand of rocker arm are you running?

RocketV8

I'm running Harland Sharp S5001 rockers. I milled the rocker pads the same amount as the thickness of the guideplates.