A good small torch might show you the pistons without a borescope.  Easy to see the difference between the D-dish and the O-dish.

Update, I'm swapping to an electronic distributor today, and had an opportunity to do some cleaning.  Grabbed this casting number on the head.  Does that help the head / piston question?

Also playing around with paint options in Photoshop.  Wife is really into white, so we are leaning toward this combo.  Still have a long list of ongoing repairs to make, *whoo*.  Did I mention it is fricking hot here?

Spent the last two weeks messing with the carb.  It was an original Aisan, but ended up opting for a Chinese copy.  I know....

Old carbie was running *fine* -- sorta -- except I had to go and mess with it.  Figured it was time to install the rebuild kit that I've had laying around since last year.  Apparently the vacuum secondary was clogged, because it looked like it has been running as a single-barrel for years.  Mixture screw was turned out 7 turns.  Biggest obstacle was sourcing the right material for the base plate gaskets, which did not come with the kit.  Who knew it could be so difficult.  After the rebuild, turns out the throttle shafts were leaking, so I ended up with a new carb anyway.  

Two big takeaways on this project, that gave me fits:

1.  The Chinese copy takes certain liberties with the design.  For example they changed the thread size and orientation of the fuel bung.  They increased the diameter of the float pivot pin.  Little things that can p*ss you off.  In my case, I ended up swapping the old top cover from the Aisan onto the Chinese carb to ease my aggravation.  My advise would be to check EVERYTHING, so you don't get surprised by, say, a vacuum hole not matching the gasket.  Or the accelerator cable stopper being too large for the hole in the linkage, etc.

2.  It took me several days longer than it should have, to figure out why the engine would stop running after about 10 seconds.  This occurred while I kept messing with the base plate gaskets, so my mind was preoccupied with the idea of vacuum leaks.  Turns out, the float needle was not *quite* seating.  I had checked it by blowing through the fuel inlet with the needle closed, and figured the tiny trickle of air getting by was OK.  Not OK.  This is what can happen when mixing and matching parts.  

Defective Voltage Regulator output is 15.5 volts but I cannot locate the device in Toyota LiteAce 1998. Do I need to remove the entire dashboard to replace it?

It should be inside the alternator by then, the KE70s had internal regulators in 1983, the KE55 had the old external regs on 1981.

Count the wires on the alty or just follow them.