72 350 K4 build

[spoore21]

I did multiple compression tests, with throttle open, after setting valves, used multiple testers each result was 90-110 lbs each side. I could get it to run one side but never both. I opted to go ahead and do a rebuild.

My concerns after disassembly:

-Camshaft has some serious pits. Looks like it was ran out of adjustment. I have a “big” cam from an earlier build. Are these interchangeable? I have the rockers/valves/head.

-Pistons did not show extreme wear. I wanted to do this one as cheap as possible. Was wondering if amyone thought rings only ok? Pistons stamped ART and I believe them to be original - 13k miles.

-Head seems to possibly has valve contact and looks to be chipped around the seat. I have another head I am considering using. Anyone seen this before?View attachment IMG_6030.jpeg

 

[LongDistanceRider]

The "fat" cam needs the 286 rocker which have no ID marks but there's a triangle protrusion above the cam end. The skinny cam uses 312 rocker which have 312 cast in the body.
Either cam can be used. IIRC the later skinny cam cambox can be used with the fat cam but not the other way around.
Don't know what to say about that valve seat. Damage doesn't appear to intrude into the actual valve seating area

 

[spoore21]

Thanks LDR. I appreciate the insight as always. Do you see anything on the pistons that would be grounds for replacement? Would like to avoid machining costs it at all possible. The spare cylinder (bright) was cleaned and cross hatched by CM before returning to me as it was damaged in transit (fin damage). Thought about using it. Also i added a pic of my spare head (dull) for valve seat comparison.
View attachment IMG_6023.jpegView attachment IMG_6028.jpegView attachment IMG_6030.jpegView attachment IMG_6031.jpeg

 

[LongDistanceRider]

Pistons appear fine. Measurements of pistons and bores will reveal the truth.
I would use the left/dirty head just because there's zero damage instead of a little damage.

 

[Boomer343]

I would use which ever head worked with the valves the best, check the intake valves for cupping on the seating surface. I use a razor blade with a light behind to check. If cupped they need to be replaced.

Either you have a very low mileage engine or those pistons are replacements. Check for an over size number stamped on top of the piston. For a low cost rebuild I use over size rings and file to proper end gap.

fat cam needs the matching cam gear but the other cam is done.