the 86's vm40ss runs a 380 main jet on a stock pipe.i was running a fmf gnarly torque, but because of the pipes improved scavenging, I ended up going down to a 360.your pipe looks like a pc plat1, which is a top end pipe so I dont know wot size to say to use , but start with a 400 or 420 and come down one step at a time. how strong it pulls up top will tell you where you wanna be, but they do run v.well when they're close to being lean, so use caution and common sense.86's are the muts arent they? Enjoy...
