Proform 66790 Length Checker Studs Review

This reduced setup time from hours to minutes and I checked the motor I made only to find I was wrong by 0.050 making it more accurate than the old one Path. Definitely worth the money because time is money.

Great tool! I used adjustable pushrods and the marker method to check the geometry. I haven't relied on this single tool alone, but other validation methods give more confidence.

I bought this to see how accurate it would be compared to using an adjustable pushrod and replacing the valve spring with a tester spring. I was within 0.075 of my actual length, which is probably fine for your average motor. If you build a motor and put your time and money into it, use a more accurate method to measure the test spring).