Looking for a piston for the 86 370, got a rod then found the piston is cracked, need P/N D9TE6110B2A, the ones I find at Rockauto show two valve cutouts where the one I took out only has one and it is in a different location. Don't know a good place for old Ford parts, any help appreciated. Patrick

 

That appears to be the standard replacement piston for your engine.
Can you post a photo of your old piston.

 

Destroked: I'm not sure about getting a picture, will try, I went ahead and got a piston and set of rings and am headed up to Alaska Saturday, will try to get some pics from up there, I figure this old piston was the factory one don't think this engine has been opened up before.

 

Ok, I remember you saying the engine had been replaced, wasn't sure if it was a used engine or a reman.
With D9TE pistons I say it was used, lots of times aftermarket pistons will look a little different but will work, if your piston only has one valve relief Ford probably made left and right side pistons for that engine, aftermarket makes pistons with 2 valve reliefs so that 1 piston will work on ether side.

 

 

As far as I know the 370-429 truck engines used the same style intake as the 426-460 car engines, but I'm not 100% sure.
Mains 95-105 lbs
Rods 40-45 lbs
Heads 140lbs
Rocker Arms (non adjustable style) 18-22 lbs
Intake manifold 25-30 lbs
Oil pump 25 lbs
Cam bolt 40-45 lbs
Harmonic Damper bolt 70-90 lbs
Flywheel bolts 75-85 lbs
Pressure plate bolts 35 lbs
Front timing cover 12-18 lbs

Here's a photo of the sequence.

 

Note sure if you honed the cyl walls, but it's always a good thing to do............

Specs from the Ford Factory Shop Manual (Engine) for Medium Heavy F-, B-, C-600 Thru 8000 Series:

6.1L (370 CID) V-8 and 7.0L (429 CID) V-8 Engines
Cylinder Head Bolts:

Tighten in Steps: First 70-80 Ft Lbs
Second 100-110 Ft Lbs
Final 130-140 Ft Lbs

Also, not sure how "dry" your engine has gotten, but I ALWAYS use compressed air to pre-lube ........................many just rely on the starter with wires pulled, but that may contribute to an "infant mortality" on those new rings....................bottom line: assembly lubes are "ok", but can fail......seen that happen on big bucks NASCAR engines.................