any thing over 1/4 mi and you dont have much chance the 8's have too much room to run you down.
i have buit some small 8's 327 and 307 and had them do well against the 355.
now for the 6 most tracks dont know what they are looing at so you could move it back more if they say #1 plug has to be at a certen place. th inline is tall so you could lower the motor also move it to the left a little too.
one motor combo to think about would be a 250 with a 4" bore even if you have to sleave it. it would wind up quicker and live longer use a lump ported head.
