I read in one of the many threads about changing primary derby torx screws to allen heads a while back. Someone stated you needed 1/4 by 20, 5/8 in long. I was in Home Depot yesterday and they only had 1/2 in and 3/4 in. Does anyone know if the 1/2 in will work. I did not have one of the torx with me to check it by.

 

Abosolutely, did it 2 years ago. Bought really thin spring type washers when I was there so the primary still gets the same amount of threads

 

Yah-- the threaded holes are deep enough to take slightly longer Allen head screws. I did this myself with the regular HD washers and the new longer ones didn't bottom out.

1/2" long screws should give you plenty of meat to hold the clutch inspection "derby" cover on at the light torque setting of 84-108 inch lbs (9.5 - 12.2 Nm).

Personally I would try to lightly turn in one of the 3/4" by hand first to see if it bottoms out, then decide from there.

 

Or just go to ACE and get the right size..