well, the previous owner had the same setup two engines ago (shop installed the cam and forgot a c-clip).  Before that shop screwed it up, it ran great with zero overheating.  I dont think a larger radiator is the key as this motor is technically not high performance. The pistons labeled as HC, are in fact nothing but stock efi 13B pistons, in the 13B block I have installed.  Im starting to think that this radioator is just junk.  I think monday I am going to call dales speed and marine down south and have one custom built.  I would like aluminum tanks with brass/copper core as its better material for dissipating heat.

Case in point, a couple buddies down the street have a monster of a sammy, 22R-e swapped and running the sammy radiator.  Stays under 200 all day long.  Im just honestly thinking this radiator is complete junk.

The pistons labeled as HC, are in fact nothing but stock efi 13B pistons, in the 13B block I have installed. 

Whilst I haven't seen the pistons you have, I have purchased pistons matching that description (+0.020" high compression pistons) from LROR and what I received were most certainly NOT stock pistons, the stock pistons are both dished and "notched" to clear the valves, the high compression pistons have virtually flat tops with the valve cut outs.

They are most definately flat tops, if you pull the pistons out of a TBI sammy, the match perfectely to the hc pistons from lowrange.  You have to think, its going from 8.5:1 to 9.0 to one.  Not much of a difference.  When the machine shop saw they were labeled hc, he said "oh yea? lets look at the technical specs and see if its true."  Sure enough, he said look, same as the B block pistons, while they are higher compression than stock for carbed, they are stock for TBI B blocks.

On to the cooling.  Bought a new stock radiator today. Truck runs at 190-195 now.  The lowrange radiator was causing the overtemp issue.  I'm just happy its at that temp considering the forecast.

Actually not going to be a bad week temp wise, pretty cool.

My bad, 8.9:1 to 9.5:1.  Having a long day.

can you describe the radiator from low range, is it like the stock type or is it plastic? etc. any pics of it? thanks'

All aluminum, thicker than stock, more fins per inch.  I checked it for water (rudimentary flow test) and it dumped just like the new one. 

http://www.lowrangeoffroad.com/index.php/suzuki/samurai/engine-upgrade/suzuki-samurai-economy-full-aluminum-radiator.html

The factory (aftermarket parts house, not Zuki) is plastic tank, aluminum core.  Another thing, the upper and lower hoses did not pressurize on the lowrange, they do however on the new one.

I wonder if your cap on the lowrange rad was working good and maybe it flowed too well to cool a zuk engine, I had a bad thermostat one time in the dead of winter here and I took it out and drilled a 1/8'' hole on the side of it thinking it would help it get warm and open up but would you believe that that 1/8 hole would keep it cool in the winter !

I beleive it.  The cap is the same one that was used with the lowrange.  Just went wheeling tonight, Got a little more technical that I should have, I did learn a valuable lesson, Sachs clutches from Oreally suck.  Other than that she ran great, hottest it got was about 205.