I'm looking at buying these 351 DO0E heads. The seller assure's me they were rebuilt 1000 miles ago with new valves, seals, guides etc. They sound like their ready to bolt on. That's exactly what I'm looking for, I don't want to have any maching done on them.
This picture worries me though. It's a shot of the heads straight off his car before clean up, looks like oil... Could this be from valve seals or rings? Should I be worried?
You know what a knurled knob looks like right? They do the same to the inside of the guides,
when you press the cutter in , it raises metal around the teeth so the stem fits tighter.Kind
of a poor discription but you get the idea. It's a quick fix bandaid instead of replacing the guides,
and imo don't last too swell.
Knurling guides is generally done on low-end rebuilds for stockers...definitely not something to consider for performance use...
You (or the seller) can pop a valve out (an exhaust would be a good choice) and check the guide. Tell us what you find (I loathe leading questions..*G*)...
IMO, uneven combustion for such a new set of heads...I'll assume the engine they were on was older...
If the price is substantial, get a written warranty of fitness (eg no cracks, surface warpage, parts condition, etc)...if no warranty is forthcoming, I wouldn't pay more than 100.00 for the set...and would inspect them carefully.
Look at a pair of GT40 heads on 97 Explorers I think they used them up till mid 98 too before switching to the GT40P heads. The GT40's will have hardened seats, flow better and you can put roller rockers on easily too.
The GT-40P's are the ones with a different spark plug location. The GT-40's will work fine with your stock headers. I am not sure who it is but someone makes headers for the GT-40P heads in an early model mustang, I think. The GT-40P heads take a different spark plug as well.