440 source

The 440 Source Stealth head is like any aftermarket head you buy. It should be taken apart, cleaned and prepped, valve and seat runout checked and guide clearances measured. The new locks are leaving nicks in the stem locking groove that must be filed down befor the valves can be removed or they cut grooves in the bronze guide. The last ones I worked with were about 8 months ago. They are using what are supposed to be Comp retainers and locks and if they are, they are the cheapest available, replace them. The springs are as good as or equal to the Edelbrocks in seat and open pressures. Many of the valve stems are scoured just below the locking groove and I attribute that to poor assembly procedures. The combustion chambers have been reduced to approximately 80-81 cc's so there is much less chance of the head gasket protruding into the chamber as before. I use the FelPro 8519PT1 head gasket up to and including 12:1 and have experienced no failures to 780 HP. Sometimes the smaller FelPro 1009 gets close to the chamber. I've found no flaws in the casting quality. The OOTB flows are not up the flows as listed on the website but are getting better as the last heads we received were hand prepped much as the Edelbrocks used to be.

Some further information on heads we tested in 2010 is here:

http://forums.moparmusclemagazine.c...formance-discussion/440-source-stealth-heads/