i have a 406 with the 262 extreme 4x4 cam with vortec heads,performer intake q.jet 750 carb for milage,and in a 89 1 ton gmc extended cab,and wow i love the torque!!!
the truck came with a 454 and previous owner pulled it out but i have to say the 406 has way more balls!!!
id say you have a good cam,but id say stick with between 165 cc and no more than about 195.
remember its a tow truck not a race truck,i give huge props to my combo and if you get some smallish heads the responsiveness and torque will satisfy.by the way with my combo id say it pulls strong to about 5000 rpms