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Nitroused383 does altitude have anything to do with you not going lean yet and being a little rich on the stock regulator and single pump? If this is a stupid question feel free to let me know.
The only reason I was running rich on the dyno is because I didn't tune it on the dyno for proper AFR. On the street it's around 11.3-11.5:1, the altitude plays a little bit of difference in my fueling requirements but not a huge amount only about 1 psi of atmospheric pressure (14.7 sea level and 13.7 @ 2000'). SAE corrected number I make 580 rwhp but uncorrected it made 552 rwhp, so my fueling requirements are less than what it would be to make 580rwhp uncorrected at sea level.
I have ran my car when it was about 40 degrees out which lowers the density altitude to almost 0 and I still haven't leaned out. The key to making power with a single walbro is using a decent amount of methanol. Talley Transam on here runs a single walbro with hotwire on pump gas without methanol, I would say he is pushing the limits. He's ran low 10's around 133-134 mph.