The Pro Comps have had a lot of bad press, and most of it generated rightfully by heads that were complete assemblies from Pro Comp. The castings aren't bad, it's the components, and the methods used in their assembly.
Those people I've talked to personally who bought unassembled castings and installed their own valves, guides, seals, and fitted them properly had no complaints. The odd sized valves used in Pro Comp heads create an issue, as they are longer than stock or other aftermarket heads, and must be purchased from Pro Comp, or distributors for their products. Skip White in Tn. carries parts for them.
I'd consider them, if I bought them bare, and I assembled and did the honing on the guides to make sure they weren't sloppy and taking out seals.

 

I actually bought my heads from Skip White and paid extra for the PBM undercut Valve upgrade and REV springs. Skip White talks a big game about their "assemblies" being so much better than the others selling the assembled heads and that's a huge load of BS. But they had me convinced. I'll be able to use the valves and springs at least.

The valves have .100 installed height, that's odd you're saying? I just didn't know that. The castings biggest problem is the massive dips under the seats from machining as well as .125" extra ridge between the valves in the chamber. The guy I sent my heads to is installing tubes in the bolt holes between the intake ports and says it'll add another 20 cfm. Never even heard of that. It's not me that has anything to prove, the timing was so ironic and perfect that he's got 3 sets of sbc heads from different manufacturers at the same time, with the same stage of work being done. He's the one that says the Procomps are "Hands down the best bang for the buck" with the extra work of course. That's the issue that had me so concerned about doing the work myself - the problems. He's got to spend the first couple days fixing the problems before doing the porting. The point I think Tony (the guy in TN) is trying to get acrossed is that you can buy the heads and have the work done to them and flow better than Brodix, Dart etc. and still have paid A LOT less than the big name/big dollar heads. I'm just excited to see what they will turn out like.

 

Congrats on the head deal. I hope you come out of it with some killer heads.

What we do over here to keep our mailboxes upright is to sink two 4x4's at least 4' deep and as tall as the box obviously and then use 5-1/4" deck boards all the way up. It takes a he77 of a hit to knock one out. They blast ours here too. I have tried two 4x4's on the box its self but the posts stay while the box gets launched to oblivion. The vertical deck seems to hold. Paint it red and they got no excuse, also make it as wide as he box but set it 6" forward of the box. That backs the truck up six inches and if they do get the guard the bow is still back 6". Visually driving the plowdriver wont tell the difference.

 

That's all I'm hoping for out of this deal, some good heads with some life expectancy. This guy really does a good, thorough job. He uses some kind of internal coating/sealant that helps preserve them also, which I thought was a nice bonus. I'm not a guy who trash talks, especially without an informed opinion anyway. I actually only set out to see if I could get some help finishing up the actual cutting part as I really wanted to finish the sanding and assembly. With the prices Tony has got for his work though, just couldn't refuse the whole package.

I did get my mailbox shield done. The deck boards are a good idea. I didn't want to have to start sinking more posts out there so I made a hinged deal with some 3/4 treated boards and some bracing on the actual post. I made it collapsable so I can reuse it for a few winters.

 

Not sure what you're referring to at ".100" installed height? Do you mean there's .100" above the keeper, or??? Stock Chevy valves are 4.91"-4.96" tall and have a .311"-.314" diameter approximately.
As you can see from this Ebay listing, the Pro Comp valves are designed to be .100" longer than stock valves. so if you use a stock valve in a Pro Comp head your springs will be compressed .100" too far, and in normal operation may bind or break the spring. These heads require this longer valve to work, so when one goes bad you need to find somebody who sells correct .100"+ valves to replace them.
http://www.ebay.com/itm/PC-SBC-Intak...b7bcf3&vxp=mtr

When you do a search anywhere for Pro Comp valves they'll come up as .100" longer than stock Chevy.

 

It seams that .100" longer valves are common to me. I can be and have been proven wrong though. Maybe for heads with sunken spring pockets or something.

 

I'm sure you meant .100 additional. Valve stem height is from the tip to the spring seat.
Just curious, is the extra length of those above or below the retainer groove?

 

Yes, thanks, forgot to add the word Extra (additional, longer, higher, taller etc.) I just wasn't aware that it was an oddity. Good question on where the added length is, not sure myself if it's above the retainer groove or not. Ultimately, I'm hoping that I won't need to be valve shopping very often.

Sending the heads down to TN to be cut is going to give me a lot more time to get the sanding, painting, suspension and assembly done. Not going to pick them up until end of Feb. now to give him time to finish his contest/battle publication. Not like I'd be done much quicker anyway but at least that lightens the burden of trying to rush. Here I was thinking I was almost ready to get this 327 put back together...

 

When I talked to the local machine shop he told me the difference is from the valve end to the keeper groove, so it adds to the overall length also, not just the length from valve surfce to keeper. The problem becomes twofold, as the spring pressure will vary if these were used in a stock head, and also the rocker wear pattern would also be off of center on the stem requiring different length pushrods.
He told me when they do a Pro Comp head they always use the correct .100+ valves, or there's too much spring pressure, and possibly spring binding also, and the rocker arm misalignment on the valve end.

 

With the extra .100 being above the retainer groove, that would mean from the groove to the spring seat would be the same length as a conventional valve stem. I don't see how that would change spring pressure then. But yes that extra above would affect rocker arm contact.