Mr.Swoogie
Member
Has anyone used the aluminum big block heads that the 440 Source company sells???:burnout::burnout:
Has anyone used the aluminum big block heads that the 440 Source company sells???:burnout::burnout:
What is the real question?
What is the real question?
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.
Edelbrocks are $500 and the Stealths are $600 (Stealths require more valve work, retainers and locks). Guides are checked and honed if necessary, spring pocket depths are checked with head surface, performance valve job, valves set to the same depth, installed heights are set, all valve springs are tested, heads cc'd, ports are blended, heads are surface milled and flows are tested before and after. Everything is cleaned, lubed, assembled and bagged ready to install.
I'm honestly more worried about the cam break in, as my block/rotating assembly is virgin from 1971 (original standard bore still)Consider yourselves 2 lucky people, you could just as well have a story of a failed lock and the mayhem that goes with it. Consider upgrading before you wish you did.
I have them on a 512 Stroker in a 72 Satellite Sebring. No problems, no issues, all I did was double check the springs and valves. Also have there roller rockers and shafts!! Excellent part and great tech support.