3/8 or 7/16 push rods

what push rod should I use? 3/8 or 7/16 push rods. I got A460 tfs heads, 2.45 ti intake valves and 1.88 ss exhaust. Manley nex tex springs which are good to 8.50 lift. Any suggestions? thx.

Big and stiff

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7/16 are better........gotta change the guide plates. may or may not rub the head hole or the upper lifter. If a guy wanted a tinker toy deal.....3/8" with a .135" wall is an upgrade....not as good as the 7/16 but better

Lem Said what needs to be said........

We run 7/16 on all our junk even the sb stuff. With as much boost and spring pressure we run it is a must.

whatbumper wrote:We run 7/16 on all our junk even the sb stuff. With as much boost and spring pressure we run it is a must.

That's why an exhaust valve will float sometimes before a heavy intake will............. (cylinder pressure)

You need 7/16 Charles.

not every 7/16 pushrod is made the same .... which wall thickness would you guys run ? .0800 , .120 , or .165 .......

do you pefer straight, tapered etc.....

and what material ....4130 or 4130 chromemoly etc.......

just curious

The bigger the push rod diameter the thinner material you can use, Lem has a real nice chart showing the strengh's of various diameter and thickness of pushrods.

Can't run a tappered rod with guide plates. Depends on the valve spring pressures somewhat. I will say that the .125 and .165 are more desirable with power adders. A .080" 7/16" rod is better than a .135" 3/8" rod.

7/16 x .080 = 13,947 @ 8.00"
7/16 x .125 = 16,079 @ 8.00"

Thx to all that replied. I'm using Jessel Shaft rockers, so no guide plates and I have the 18 bolt TFS heads so the push rod hole is already opened up. So which is better tappered or straight?

I'd stick with the strait stuff if you have clearance, It will save a few $$.

The "hole" in the 18 bolt stuff is longer but no wider.....it still begs to be checked.