Hello Chuck .
It's the Tall Fella from Australia . I have run a few Red head OPS 67 motors over the years and usually used no more than 30% Nitro . With the slide carby , they work well if the O - Rings are in good shape . Depending on whether you have the factory OPS RC Mixture control adapted onto the carby , in which case there are 2 . Now in the middle of the sliding barrel , there is a screw head for the low speed mixture - set it almost flush with the end of the barrel . As for the main / high speed needle , start at 3 turns and gradually lean it off after a few tanks . Over here we call it 4 Stroking - it's that rich and the pipes are listed on the original OPS paperwork of having a range of 22 - 38 cm from the plug to the major dia. of the pipe . We generally go ~ 32 cm and get respectable performance . Hopefully this helps with your enquiries . They also come with 2 different head button options , standard - dome and Nitro - open chamber . And a head clearance of 14 - 16 thou.
Regards
Ian Baas
Tall Fella Racing
Australia
