Eddy heads and 3/8th" push rods clearance issues.....?

[Cranky]

The 6000 series heads.....6091/6092 to be exact. Was asked if there would be any interference with a 3/8" push rod and the head and I really couldn't answer it with straight yes or no reply. Seems like I remember reading that with the higher lift cams, there might be a problem with the PR's touching and to at least check it....?

 

[lewtot184]

I don't have an issue with a moderate lift cam. rollers need shorter push rods and higher lifts combined with shorter push rods (increased angularity) can get you into interference with about any head.

 

[Yatzee]

The 6000 series heads.....6091/6092 to be exact. Was asked if there would be any interference with a 3/8" push rod and the head and I really couldn't answer it with straight yes or no reply. Seems like I remember reading that with the higher lift cams, there might be a problem with the PR's touching and to at least check it....?

There will be a bit of an issue but not just at the openings in the heads but also on the underside of the rockers if your using the adjustable type. When the valve is fully open and the rocker is at maximum tilt, the rod will hit the underside of the rocker so it must be clearanced. Depends on the cam lift. You can run 5/16 rods with pretty stout valve spring so I'd check with the manufacturers for the limits. You might be quite surprised.

 

[PurpleBeeper]

I've heard this too. The good news is that there looks to be plenty of meat on the heads to do some clearancing in the "holes/slots" where the pushrods go down into the valley through the heads....plenty of meat to clearance if necessary IMO.

 

[451Mopar]

Not sure with 1.5:1 rocker arms, but with 1.6:1 rocker arms the pushrods were rubbing the holes in the heads.
That was with the Hughes solid STL4650BS cam, 0.614"/0.627" lift on a 400 low deck stroker.

 

[69a100]

I see a conflict of interest here as there's some different part #'s your asking about, but I'm sure you can find your answer here as they do mention about checkin clearances But I didn't dig hard lookin about grindin and stuff. Good Luck
http://www.edelbrock.com/automotive/misc/tech-center/index.php?query=6091&submit=search

 

[Cranky]

I have a set of PR's for sale and the buyer was worried about clearance issues in the heads and knows to check the rocker clearance....and if he doesn't, I'll let him know to check that too.

I see a conflict of interest here as there's some different part #'s your asking about, but I'm sure you can find your answer here as they do mention about checkin clearances But I didn't dig hard lookin about grindin and stuff. Good Luck
http://www.edelbrock.com/automotive/misc/tech-center/index.php?query=6091&submit=search



View attachment 593568

The two part numbers I listed are for the same head....but they are one number for a loaded head and the other number is for a bare head. Soooo, please do your research

 

[69a100]

Like I said, I didn't dig that deep about it. Just tryin to help.

 

[Cranky]

Like I said, I didn't dig that deep about it. Just tryin to help.

Yup.....btw, I'm also selling the heads to the same guy. I bought them years ago and well, never used them. Figure by the time the divorce is over, I won't have any money to put anything together.

 

[451Mopar]

I specified the setup where we had clearance problems with the RPM heads because the clearances may be different with different engine, rocker arm, and cam combinations.
I think the change in rocker ratio was a big factor (pushrod moved closer to pivot of rocker arm), along with the engine being a low deck 400 (shorter pushrods) compared to a taller deck 440 (longer pushrods), and the total lift (movement of the pushrod further inward when closed and max lift than if lower lift cam was used.) After bending an unknown brand 3/8" pushrod, we just dropped in some good SmithBrothers 5/16" pushrods (I think 0.083" wall?) Engine has been running mostly track and some street for around 5+ years with no problems.

 

[Sweet5ltr]

I'm running the RPM heads on a low-deck stroker, 1.5 Crane Ductile Rockers - 3/8" (.145 wall) pushrods from Steward Performance. No issues with a .606" lift SFT camshaft.

 

[moper]

All the RPMs use the same pushrod hole placement and size as far as I know. Part of the "check and correct" I always talk about involves clearancing the pushrod holes. Same thing on 'Source Stealths.