I need 2 change my power valve ... Is there a formula or sumthin 2 calculate which size I need ? Thankz

Hey Jason,what you do is hook up a vac. guage to a manifold port and measure your vac. at idle in gear...if you have a stick measure the vac. at idle in gear then ride the clutch abit and measure the vac. Subtract 2.0 hg and thats the base for your power valve.ie get a vac. reading of 7.5 inhg your power valve would be a 5.5inhg.Good luck C-yaa o1