Easiest way is some super strong velcro on the battery and tray... Then some foam - i use a cut up shoe insole to pad the gaps. ATB... Sorry no pics to hand...
You can use the optional traxxas hold downs made for lipos I use 2 8000mah lipos or you can use velro straps and cut slots in chassis too...
how do you like those motors. I am looking for some brushed motors for my brothers new emaxx and he wants something fast and cool running. about how fast do they go on your setup.
This how I did mine, I was able to use (2) 3s 5400mha lipos in the 3905. I think the straps cost me $15.00?? it’s easy / no issues at all.. PS. use the Traxxas 6 cell foam to fill in the gap so that the lipos don’t slid left and right.. (see first picture)
For taller batteries you can gain some clearance by just loosing the four very long screws that fasten the stock batt hold down blocks on to the chassie, so when you put a tall lipo in with the stock strap it pulls the hold down blocks up to the predetermined screw head hight. Also I have just pinched a piece of velcro under each of the stock strap hold down blocks.
They are awesome can hold a wheelie down the street ...alot more torque ...run cool never got over 98 in foot tall grass bogging it down esc was 110...lol....I just got my replacement bellcranks and I will shoot vid and gps it ....highly reccomend it for 99 bucks ...top speed I'd guess 40 give or take few mph ....gps will tell the truth...