Adjustable pushrod length checker. You can buy one from Summit etc.

 

Will i need one of these as well? http://www.summitracing.com/parts/PRO-66790/

Also after i adjust the push rod checker, how should i measure it to get the most accurate reading?

 

no need for a mock up rocker arm, I use the rocker itself I intend to use for mock up, a adjustable push rod comes with a predetermined min max length, the comp cam one I bought screwed all the way in is 5.800 and all the way out 6.800, there is a dotted line on each half and one complete revolution is .050 iirc on mine, so no need to have a tool to measure it, just know it's closed length and as you screw it out count the turns and know how much each revolution adds

 

Thanks thats very useful info. I seen there are many different length ones, which do you recommend for a 351w? (im guessing 351w's use longer push rods?)

 

yes 351's will use a longer one............can't say I know the answer to that one since I haven't built a 351, just many 289/302/347's

 

I guess ill just do a little searching and take a educated guess, and your suppose the measure the length when the lifter is off the lobe im guessing?

 

when it's on the base circle meaning the flat

 

if you get the one that MJR said (same one i have), just look at the line and count how many turns it is. each rev. = .050". any other one will have to be measured with a set of verniers to accurately (i know i dont need to say it, but DONT use a tape measure...)

FWIW, the pushrods i measured up my truck engine were 6.250" so expect something in that range.