I've got a new question for the experts.......I 'm replacing my stock heads for "C" with Harland Sharp #5001 roller rockers, guide plates, OEM (steel gaskets.016??), and a JM18-20 camshaft. What length of pushrod will work?
Thanks
joepenoso

 

Joe, there are a few ways you can go about this. You could probably use a 9.7" pushrod and be acceptable. If you were to decide to go this route I have a gently used set of Comp 5/16" pushrods I would make you a killer deal on. If you want the optimum length pushrods for your engine noone can tell you without checking the mocked up engine.

The correct method is to mock up the engine with an adjustable pushrod on the #1 cylinder intake valve using a light tension checking spring in place of the valve spring. I would initially set the adjustable pushrod to a length of 9.7". Using either highspot blue machinists ink (prefered) or grease on the valve tip as a witness marker, roll the engine over by hand and observe the total width of the roller path across the valve stem tip. Then adjust the pushrod slightly longer to 9.75" and repeat. If the witness mark gets shorter continue lengthening until you find the pushrod length that gives you the shortest path of travel across the valve stem tip. If the witness mark grows when you lengthen the pushrod then obviously go the other direction and shorten it. Don't be concerned with getting the witness mark centered on the valve stem tip.

Now move to the #1 exhaust valve and repeat. If you are lucky you will get the same length as the intake. If not you will have to choose between splitting the difference between the int./exh. or ordering eight of one length and eight of another.

 

thanx chadman, been wondering that myself

 

Thanks Chapman
joepenoso