Don,
was re reading your post on this (as I said had 575, oil pump, lifters etc, V&H true duals, PCIII and got numbers similar to your first dyno run). Was looking for more torque. I like the numbers you got but am reluctant to change engine alot . you said the cylinder heads weren't quite right-how so? How long did it take for them to complete the job? Do you remember a ballpark $ on job? Trying to balance this vs. cost of say D&D fatcat 2:1 with torque increase or put the money into getting the overall performance from engine upgrade. This is what my winter project will be after football season is over. Any help is greatly appreciated! John I guess in the end what I am trying to avoid is " the enemy of good is better" 
Oh boy.... John, I try to generally avoid much of the he said/she said that becomes concomitant to discussing the problems that were had. There are two side to all such discourses of course. And some are just almost religiously for or against a particular vendor. So it's difficult to ever have a discussion without it becoming an interrogation or a sermon. Having said that; here's what I ran in to in my work with Zippers.
The two problems with Zippers were their inability to meet (redundantly) their own suggested deadlines as to supply and the quality of the final machine work on the cylinder heads.
They were never hesitant to make promises as to when to expect parts to be available or be shipped. They were in fact willing to happily make such promises repetitively. That the promises had no basis in reality was the problem. Eventually they learned that it was better just to say "sorry, I just don't know yet, but we really are trying." But it took them a long while to understand that reality rather than hyperbole was truly the more desirable tack.
That was the nuisance. The annoyance. The bothersome part of working with them. Had everything else been ok that could have just been chalked off as yet another company getting in too deep; being too busy at a particular time to meet their demands. You can accept that (once) and move on; if that's all it is. Unfortunately it wasn't.
Their work on the cylinders seemed beautiful. Fit was perfect. No problem on the jugs or the mate of the jugs to the pistons. Their work on the cylinder heads, however, was very very pedestrian. Average; at best.
The final polishing work that I'd been told was part of the job simply wasn't. In fact the surfaces looked like they'd not just come directly from the CNC machine. But as if they'd come directly from the CNC machine with dull tools in use. That was bad enough. Worse, however, was that the valve job was just abysmal. One cut (angle) on one exhaust valve. Two valves set way way too deep. Other issues as well. Though I'm sure it will vitiate any "warranty" on the entirety of the job I might ever attempt to discuss with them I'll admit now I did the valve job over again before installing the heads. It was just that bad. And obviously so.
Fortunately I'll never have to concern myself with their warranty. They'll never lay machine or other tools on parts of mine ever again. I very much like the Thundermax system with the autotune addition. Definitely a fan of that system. Would recommend without hesitation. At least in my experience, however, the headwork looked like it came from an apprenctice machinist who didn't know a valve machine from a candy bar dispenser.
Unfortunately many would unpack the new pretty parts, say to themselves "oooh, new pretty parts" and simply never know nor recognize the difference. They put it all together, or pay someone to and it would have started and ran. Then in 10 or 12k miles they'd have burned a valve (or worse) and simply been left to wonder.
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Topic: "103 Muscle Kit" from Zippers post race summary (Read 8660 times)