Help, Pipes turning blue....

[WMarshy]

... My screws are turned out over 4 turns...

Im not trying to tell you how you should or should not have your carbs setup, but usually when your that many turns out its time for the next size larger jets...

As they already stated, you are on the lean side and need to turn out your screws to richen it up. Knowing how you read plug color will take you to the next level and confirm the changes your making. From the sounds of it, you need to richen up the pilot circuit by going to a larger pilot jet. The '78's came with 45's so the next larger pilot is 47.5, they also came with 137.5 mains and if your running a stock air box then they should be ok, but 140's would probably help you out b/c of your pipes. Do a little search on pilot jets as there are two types that look very similar and only one works correctly. If you havent taken a trip into your carbs its probably time to figure out what height all the needles are. I lowered the clip one notch on my '79 (ie. raised the needle) to richen it up. Needle height has more effect on mid range and not so much off idle to ~3500 rpm. Mine pulls like a funy car after 3500 and has a good plug color. If I had to guess, yours runs simular to mine, lacks power off idle to 3500rpm then runs great? My '79 has 42.5 pilots and Im searching for 45's, once I get them in Im positive it will have that low end torque everyone speaks of. Try tuning your screws first, if you find that your 4 turns out then its time to consider going up in jet size, just be careful not to tighten those screws too much.