440ex HD head studs

[lexus-10]

I'm building a 440 and have some gt thunder hd head studs on order, but they will not be hear until the end of the week. The machine shop wants to retap the holes tommorrow. Does anyone know what the thread size of the gt thunder head studs are?

[jcs003]

copied and pasted from: www.Gtthunder.com

Installation Instructions

You need to first drill and tap the cylinder to accept the new studs.

Hole machining

7/16-inch course thread. Drill holes with a 3/8 inch bit. Use only a roll form thread tap. I use a tin coated tap from MSC Industrial Supply part number 07463268. It is always best to have a machine shop do this procedure in a vertical mill to ensure proper alignment.

Be sure to hone cylinder after studs are installed.

Install the new studs using Permatex sleeve retainer on the threads.

Be sure to install to the correct height.

The studs must be the correct distance out of the top of the cylinder.

Front – 2.436”

Rear – 3.188”

Sides – 1.929”