So now I have input on Pro Comp aluminum heads, and it ain't good.
Last fall I got a smokin deal on a pair I found on the local Craigslist. $500 for the pair and a set of ARP head bolts tossed in too! Brand new, but had been installed on a SBC, but never started up.
Well I was looking for a pair of old "fuelie" heads, but what the heck, these were too good to pass up.
Famous last words! I picked them up and during the off season I installed them on the 327 in my Austin gasser. The heads were angle plug, which created some clearance issues, but I got around that. Installed a new set of roller tip rockers, and a new cam while it was all apart.
A couple weeks ago I started noticing one cylinder was not firing well at idle. Pulled the valve covers to find one rocker had a bad roller! It also ate up the valve stem a little, so pulled the head and took it to the local machine shop to have it looked at.
Machinist told me the next day that all the valves were sloppy in their guides! Said it appeared someone bored the guides without honing them to fit each valve correctly. Pulled the 2nd head and he confirmed it also was assembled in the same sloppy manner and all valves guides were sloppy.
Wasn't too excited aout having to replace all the guides, especially when I found out they're all oversized OD also! The new guides would have to either come from Pro Comp, or one of their distributors like Skip White in Tn.
At that point I decided to cut my losses. He had a pair of old 2.02 camel hump cast iron Chevy heads with all new SS valves, hardened seats, new guides and seals, and chambers CC'd. I gave him the crap Pro Comp heads and $150. and walked out the door happy.
In the end it was a cheap lesson, and one I wont forget. I'll never buy Pro Comp again, but if anyone considers them be sure to get bare heads and have your local machine shop assemble and fit them. Don't let the idiots at Pro Comp toss them together!