440 Source Aluminum Heads

Latest Stealth heads to come through the shop still have a problem with scratches in the valve stems, caused by the assembly procedure, right around the lock groove. Sometimes you need to replace the valves and sometimes you don't. This time we didn't need to. The retainers aren't too bad but the locks SUCK. The castings are very good in my opinion and far more uniform than the Edelbrock RPM ones. This time the valve guide clearances were all good but we always do a better valve job on the heads and replace the locks and retainers with Comp Cams 741-16 retainers and 611-16 locks. Any aftermarket cylinder head must be surface milled to make the head to block surface flat, these are no exception.

Do not run these heads OOTB. There were aluminum shavings and small chips underneath the valves inside the ports. I've seen this in all cylinder heads, this isn't exclusive to Stealth heads.

Combustion chamber cc's were 82-83 with one end larger than the other. Milling them flat but cutting .005" more off the larger side got us to 80.7 to 81.4cc on all eight cylinders.

Valve spring pressures when we set the installed heights @ 1.88" were 136#-143# and @ .500" lift 307#-320#.

Airflows before and after the service preparation:

Lift...............OOTB IN/EX.....................Prepped IN/EX

.100..................69/55..............................73/61
.200................145/110...........................150/127
.300................210/150...........................212/170
.400................245/183...........................254/198
.500................265/207...........................283/222
.600................278/220...........................297/240
.700................283/229...........................295/250

Yep, OOTB these heads should get you 500 HP out of your 440 if you know what you are doing and 620 HP on a well prepared 440 with service prepped heads, valve springs and a roller cam.

Yep, they are worth the money.

Nope, no hesitation, I'd use them.

One more time, all out, these heads can get you 750 HP from a pump gas 451 stroker. I don't recommend buying these heads with that purpose in mind, but if you already own them they can do it.