what is the actual head clearance of RB R3?
I measured the head clearance with the stock silver .3mm shim on, using the solder trick and I found it to be .5mm !!!!
I am running the engine with 16% nitro fuel.
Isnt ,5mm head clearance high for 16% nitro or have I messed up somewhere on my measurement?

We actually measure in inches not mm.
I myself only run 16% nitro content and have always used the .3 shim provided. You will be fine. Trust me.

It depends a bit on how high you are compared to sea level.
At sea level .5mm is ok for a 12 engine. At 550 m we run .45mm clearance (not shims)

Shush!! No need to make everybody aware how backwards y'all are

I thought actual head clearance for .12 engines at sea level for various nitro % fuels was as this:
16% nitro .36mm - .4mm
20% nitro .4mm - .5mm
25% nitro .5mm - .6mm
30% nitro .6mm - .65mm
so for 16% nitro, that I am using, .5mm is kind of high.
Wouldnt someone gain more torque if .36mm-.4mm actual head clearance is used, instead of the factory .5mm clearance?

Not to worry - some of even have calculators to go back and forth

not so patiently waiting for that R3RC...

Who did you order the engine from?

Hopefully not the same person I just ordered from

Hehehe, get back to work dude.

Didn't, no one has it listed, don't know where to order from. I can only find the original R3.

Oh, and I'm waiting patiently for a response...

Try calling around. Some people are pretty slow on updating their sites. Hopefully Jamie can tell us who he has shipped to.

I called three places that I order from regularly and they don't have it.

Have you tried:
http://www.murnanmodified.com/index.php
and
http://gasrccar.com/