427 Push Rod Design

[Chris H.]

Was considering replacing the original push rods with Crane's OEM replacements. I noticed the tip designs were different. The Chevy pushrods have a "cup" at the end where the Crane's do not.

I would like to use the Cranes as it's a one piece design, etc, but am concerned that the Crane design is not compatible with the Chevy lifter and rocker.

Am I being being overly concerned?

[Joe C.]

Re: 427 Push Rod Design

Was considering replacing the original push rods with Crane's OEM replacements. I noticed the tip designs were different. The Chevy pushrods have a "cup" at the end where the Crane's do not.

I would like to use the Cranes as it's a one piece design, etc, but am concerned that the Crane design is not compatible with the Chevy lifter and rocker.

Am I being being overly concerned?

Yes you are.
The new pushrod has more contact area than the old one which has a pressed in hardened tip.

[Joe L.]

Re: 427 Push Rod Design

Was considering replacing the original push rods with Crane's OEM replacements. I noticed the tip designs were different. The Chevy pushrods have a "cup" at the end where the Crane's do not.

I would like to use the Cranes as it's a one piece design, etc, but am concerned that the Crane design is not compatible with the Chevy lifter and rocker.

Am I being being overly concerned?

Chris------


Are these 7/16" or 3/8" pushrods?

[Chris H.]

Re: 427 Push Rod Design

Joe, 7/16ths. My concern is the Chevy tips seem to have a larger "funnel" than the Crane tips. I'm concerned that not enough oil will get pushed up the Crane rod to the rocker.

[Jerry M.]

Re: 427 Push Rod Design

Chris,

Chevy offered a set of pushrods through their Chevy Power catalog that looked a lot like these when we built my '66 427/425 around ten years ago or so. One piece design without the traditional hardened tips. Four pushrods wound up wearing down and basically started to disintegrate in short order.

Replaced them with traditional design and no problems since.

You really don't want this problem.
Jerry

[Chris H.]

Re: 427 Push Rod Design

Joe, I was mistaken, they're 3/8ths.

[Joe L.]

Re: 427 Push Rod Design

Joe, I was mistaken, they're 3/8ths.

Chris------


Good. The 7/16" pushrods were originally used only for 1969 L-88 and ZL-1. I do not recommend their retrofit to any other big block.

Both the Crane and GM pushrods you picture are what's called "180 degree" pushrods. That means the tip is designed to operate through a 180 degree arc. This is sufficient for the vast majority of applications. Welded ball type pushrods, used on many later engine applications, are "270 degree" pushrods.

[Mark E.]

Re: 427 Push Rod Design

How to Hotrod Big-block Chevys has a pictorial history of the various factory push rods and PNs. If I was in town I would refer to it and give you a more useful reply.

[Chris H.]

Re: 427 Push Rod Design

Thanks Mark, I actually have that Book. I'll check it out when I get home tonight.

[Mark E.]

Re: 427 Push Rod Design

I installed Crane push rods in my LS-5 a couple years ago, and the engine seems happy.

Your L71 is a different animal, of course.