Pushrod length help

[72smallairparticler]

My build:
1975 360 LA block
Speedmaster heads
Custom grind Comp Cam from IMM engines: 234/234 Duration .533 Lift HFT, 108 LSA
Howards Anti-pump Hydraulic lifters p/n 0424
Stock 273 Adjustable Rockers on banana shaft arms

Looking for pushrod length to order but im curious if anyone has suggestions on best way to find the right size.

I grabbed the wrong double round ended pushrod measurement tool to install on a fresh lifter and tried to figure out where the base of the cup would be.

Question - for Cup style pushrods: When a vendor like Summit or Jegs etc say "7.389 in. Long" Which length are they measuring? A or B?

Thanks in advance

 

[Uncle Bob]

Question - for Cup style pushrods: When a vendor like Summit or Jegs etc say "7.389 in. Long" Which length are they measuring? A or B?

I was told to measure from the ball end to the bottom of the cup. So I had to measure the depth of the cup then subtract that from the overall length to get to the length needed to order a set from Home - OE Push Rods - Manufacturer & Distributor.

If you read a lot of threads you will find that few if any have had luck using off the shelf pushrods with 273 rockers.

I made a measuring tool by cutting piece out of a wrong-sized original pushrod and tapping the two remaining pieces to join them with a piece of 1/4"all-thread with a locknut.

 

[72smallairparticler]

Yeah problem is that I dont have any cup ended pushrods to test with, but thank you for clearing up that side of the measurement for me. I can get a pretty reasonable measurement from the ball to ball style tool pressing it up against the rocker, but definitely feels it'll be off a bit.

 

[Newbomb Turk]

Yeah problem is that I dont have any cup ended pushrods to test with, but thank you for clearing up that side of the measurement for me. I can get a pretty reasonable measurement from the ball to ball style tool pressing it up against the rocker, but definitely feels it'll be off a bit.

On cup type pushrods you can use one of two measurements.

One is overall length and the other is effective length.

When you use a cup style adjustable pushrod you are measuring for overall length.

Doing what you are doing is measuring effective length.

Just make sure you tell the pushrod manufacturer which measurements you are using.