Originally Posted by
buglite62
I have the same prob (if it is one) with my 7 port, it runs 260-270 lowest I've seen is 243 but seems to run the best at 270. Question I have is, it ran 265 in my 3 5 minute heats but on my 15 min main it came off the track at 312. I could tell it was leaning out due to the fact I couldn't clear the big tripple anymore and loss of pep. Does anybody tune it a little on the rich side to make up for longer runs? I did open the HSN almost a 1/4 turn during our warm up thinking that may happen. I'm running a 7 port, 2 1/2 gal, 6.5 restricter, short needle mod, 30% OD in a 8b. Thanks guy's
add a shim to the head! You should have a minimum of 3mm. 1-2mm and 1-1mm
the other thing is you may have air leaks. either arond carb,carb needles,backplate. but I am going to assume you have already checked that. One last thing, check your idle gap! set it at about 1-mm then never touch it. then set the hsn 1/2 turn in from flush[this is for the gen 5-5.5 carbs] the carb with the red go on the front. then turn lsn in 1 full turn from flush. I also only use an os-p3 turbo plug or odonnell 77t. I do not use any other plugs as the engine takes a sht on me if I do. They like the hot plugs. But from what your discribing it sounds like you need a head shim.