High Altitude weber jetting recommendations needed

[tfiv]

I'm running the Bogus Basin hill climb this weekend and need some jetting help.

The top of the run is about 6000 ft. I live in Portland (nearly at sea level) where my track thrasher runs perfect. My issue last year was increasingly poor throttle response the higher I got.

The engine is a fresh euro SC 3.0L: stock cams, 1.5" headers, sport muff, 40mm webers, 36mm venturies, 60 idle jets, 150 mains. I haven't taken them apart to see which emulsion tubes.

Recommendations appreciated!

[1QuickS]

Simple rule of thumb is to decrease mains to 145 to 140.

A forum regular on the Pelican site has a tracked, solex cammed 2.7 w/34's @ 5500 ft and runs 150/155 mains, 200 Air Correctors and 50 idles with F3's.

The 200 air correctors are quite large but I suspect they help lean out the F3's at the top end. He would probably use 155 mains at sea level.

[edmayo]

I believe the basic rule of thumb is 2% change every 1,000ft. You have roughly a 12% change, so if you ran a 150 main at sea level change to a 135 for the 6,000 altitude.

[tfiv]

Thanks for the help, I borrowed a set of 140s. I was able to shave 2 seconds off my time from last year.

I actually had none of the hesitatation even with the 150s though, so I guess the problem had more to do with my worn out motor. Honestly I couldn't detect any difference in the way it ran with the smaller jets.

[Neunelfer]

I'll second the 50 idles living here at 4,500.