Once I got the hat nozzles set, I never have changed them--they're a little hard to get to. The port nozzles take a little doing to balance the cylinders and keep consistent EGT's on all cylinders. Again, after getting those set, they only change if the density altitude changes by a lot. Out here in the west the track elevation differences require changes. Tucson is at 3075' altitude and Phoenix, IIRC, is about 1400'. Therefore, different sets of port nozzles. Day to day or hourly tuning requires only a bypass change.
It's also important to keep the fuel pressure constant, so that complicates things a little (changing nozzles and jets changes fuel pressure). I use an app that keeps track of all of it and spits out a bypass size, based on density altitude.
Jim
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****'63 Tempest, 475" IAII, Wenzler Super Chief heads, converted to blown alcohol, Birdcatcher, Littlefield 10-71 high helix. Best pass to date: 7.67 @ 181.59 (1/4 mi.), 4.95 @ 143.67 (1/8 mi.), 1.18 (60 ft)
7.75 @ 178 pass:
https://www.youtube.com/watch?v=Iez3...ature=youtu.be
First seven second pass(7.98): https://wwwoutube.com/watch?v=DK17...ature=youtu.be
Thanks to Paul Carter @ Koerner Racing Engines
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