Hello mariomart,
Still have a lot of unanswered questions yet at this point,this is a total experiment for me.( ksoc ) posted a picture of a tank for me to see that ( bullyhys ) had built with four drive gearboxes.He didn't use HL controls though,he used duel ESC's to control his.
My goal here is to stick with all HL equipment,trying to hold the cost to a minimum and also like the HL controls overall.Seeing I only paid $20.00 dollars for the tank itself and $140.00 dollars for the two new parts tanks,this will be a cheap experiment.I figure the worst that will happen I may burn up a board or two,but I hope not of course.I can always take out one set of gearboxes and add Idlers to the front and still have a good working tank,just not end up with the power I want.Very happy with what I've got so far,very good track system.

The original way I had planed on doing this there may have been more problems,a seperate battery to each board.This may have resulted in more conflict between the boards like you refer to above.After some advice on another post I made (need advice on electrical question)several guys posted some ideas and comments.(darkith) has got me going in the right direction and showed me a better way to set up the batterys and boards.What I'm going to try(getting close to this now) will be to use a Y connector running both batterys in parallel to the first board and then continue on from that board to the second board.By doing this the power to both boards will always be equal.I do expect there will still be some minor variations between the actual motors and boards but hope the controls will be able to withstand this.For direction controls(steering the tank straight)I will still rely on the trim controls on the transmitter if needed.Like I say I'm still experimenting here and it could end up not working.Stay tuned,will have some results soon good or bad.I would love to see this work like I hope it will.It will make an in-expensive way for guys to have a 1/12 scale tank with sufficient power and the fun of building one.I would also like to see one of these painted with a really good paint job,there are some guys on here who do fantastic paint jobs on their tanks.I don't have that ability,wish I did.
Thanks all----BIGMIG

One thing I will add there will be one small board connected to both big boards by way of a Y-connector from small board to the two big boards.Hope all this makes sense.