Scored Some Gt40ps. Need Some Diy Direction Please.

MagnaFlux typically uses powered iron and a very large magnet. Any kind of NDI (Non Destructive Inspection) requires that you clean all the carbon and sludge off a part before testing it. That's why a dip in the hot tank and carbon removal is standard part of automotive machine work. Knowing where to look is just as important as knowing how to look.

See View: https://www.youtube.com/watch?v=Oag_fnwG5F4

Unless you are lapping and installing your valves, keepers, and springs yourself there's really no point in disassembly. Just drop them off.

spend the money and have them hot tanked and magnafluxed before you invest any money in parts. You will want them to install new guides and probable a light mill as well. I prefer the TFS springs over Alex's. It's going to run $3-400 to do it right, assuminng no bent or bad valves and you dont need to regrind the seates/Those heads look like they ca,e offf a high mile engine with a lot of carbon in the chambers. What's with the rust? Have they been sitting outside or did a HG go?

P heads require a different set of headers than normal GT40 due to the plug angle.

The bbk 1515 shorties work fine. The TFS spring kit has stronger spring which enables you to run a bigger cam at higher rpms. depending on your cam you may want to look at other kits but if your running a low lift stockish cam you will be ok.

The HG could have been failing and causing coolant to leak out the top of the gasket not into the cylinder, but that looks like they have been sitting outside for a while. Regardless, the machine shop will mill them straight if after the magnaflux says they are ok. The TFS springs are better quality and strength as Alex doesn't say his source and if I remember correctly the TFS comes with retainers and/or keepers. If you plan on running a cam with a mild ramp up and not exceeding .525 lift, then Alex's springs should be ok.

167k miles is a lot and I would be surprised if those seats and guides are not shot. If it were me, I would add up the cost of hot tanking, milling, magnafluxing, guides, seals, valve job, and also if any valves are bad. If it comes out to more than $4-$500 to complete the heads properly, I would save up for a set of new TFS or AFR's. Personally I am not a big fan of P heads as changing the plugs are a PITA.