Timing cover - drilling for dip stick

[Rob Z]

My replacement timing cover does not have the hole for the dip stick. It has the place for it, just not drilled. Anyone know offhand what size the hole needs to be?

 

[68EFIvert]

I used a 3/8" long drill bit I got from Sears. Make sure you hold it very still or use a drill press. Mine fits slightly loose, not enough to leak oil. I attribute that to not keeping the bit from moving slightly as I was drilling.

 

[gwstang]

I am using the timing cover that came on the '90 5.O HO motor that I have in the 66. I had to drill the hole for the oil dipstick also. A little dab of silicone will seal the tube up very well as it fits into the cover.