Is there a noticable ridge at the top of the cylinder, or is that just the shadow of the head gasket? If it's a ridge, you may need to bore the block to .30, or use the .20 pistons in another engine. How much carbon is there in the rocker arm valley? The far left intake valve looks like it wasn't sealing too well.

 

At the very least I would get the heads redone..they are looking a bit tired..the block seems to have a ridge at the top..you can clean this yourself, with a drill and a ridge reamer

 

and quite a bit of atherosclerosis in the cooling passages. I wouldn't want that clogging the radiator.

 

Lots of scale in the water passages. Put a filter on the top raditor hose, as junk is going to be flying out of the block after the work is done.

Was your compression good before you started?
Is this just a valve job, or are you planning on doing the lower end also?

 

Looks like that engine has ingested a large amount of polluted LA air. The best way to clean it is with some Lake Erie water in a bucket, but make sure you dilute 2:1 with some distilled water so the Erie water doesn't damage the piston tops! :joker:

 

pull the engine completely apart and have it tanked. have the cylinders checked for "taper" and have the piston to wall clearance checked. go from there. IF all you want is to overhaul it then a ridge reamer/sunnen hone job will get you decent results BUT I recommend checking the pistons VERY carefully as most get cracked skirts over regular use(over time) and a "good" shop can "power hone" a block out to .030 from .020(at least my guy can)

 

Thanks for all the replies (except Jim's :lol. I think I will take it apart and get it check/cleaned at a machine shop as I don't know its history.