440 stud kit

[426ex]

I know you need the stud kit when taking a 400ex to a 440. The kit says to use a roll form tap for tapping hte holes. What happens if you use a regular tap?

[440_Turtle]

a roll tap actually makes the threads stronger as it is not actually removing material but redistributing it. a regular tap will work but if you have access to a roll tap use it.

[400exrider707]

The regular tap actually cuts material out of the hole, where as the roll form, actually forces material out of the way and compacting it into bigger threads. Use the roll form or dont bother doing it at all. Also the heavy studs are only a necessity with compression higher than 11:1 IMO.

[F-16Guy]

I would use the roll form tap; I think that's where a lot of the extra strength comes from. You might be able to get away without doing the stud kit, but you have to ask yourself how many times you want to take your quad apart. I sent my cylinder to GT Thunder, and I got the stud kit installed, cylinder honed for new rings, and a new laminated steel head gasket for $160 shipped. It was well worth the money knowing that I'm not going to crap out a head gasket at the worst possible time.