Re: 170 GPH Holley mech fuel pump and 8AN lines
Excellent point and one I should have mentioned - I installed the jet extensions and associated change to the float (allowing full range of travel, since regular float will bottom on the extended jets) when I installed the .130 viton needle & seats.
The .130s had to be adjusted all the way down until no threads were showing / graspable by the adjusting nut - just to get the fuel level to nudge the very top of the sight glass on the float bowl. Quick drive around the block confirmed this was useless due to fuel sloshing out the vent on turns or braking. Put the .110s back in and regained float adjustment to mid-line in the glass, but still had the lean-out in 3rd and 4th.
Pulled .110s out along with the float assembly. Iteratively bent the tang on the floats upward about 1/8" and re-assembled float into bowl, checking how much range of adjustment I'd have. Eventually settled on an adjustment range that didn't over-fill or under-fill the bowl based on where an imaginary line at 3/4 of way up the float was, in relation to the sight glass. Worked perfectly with the .130 vitons installed, with full range of adjustability, no bogs or slosh issues, and no lean-out in 3rd and 4th (so far - temps here are in mid-50s this time of year; will wait to see what we get next summer once this and the 1/2" fuel line setup is there).
For now (in 40-60F weather) this simple, old-school carb & mech pump seems to be "working as designed" and "good enough" for my needs with air/fuel ratio being 14.7:1 idle and cruise and mid-low 12s when WOT in all gears. Close enough for Sat early morning drives through the twisties in a car that I don't park/leave anywhere but in our garage.
Much cheaper than the "plan B" I was considering with Aeromotive's Gen 1 Stealth Tank (their Stealth 2's foam scares me longevity-wise) which would then go to "plan C" if needed with a Stealth Sniper setup (which requires solving/preventing a ton of RFI issues that need debugging from what I've seen on forums, vs. this simple solution). Sure the EFI would be easier to tune (I've been tuning laptop load/RPM cells since 2005 on AEM, MoTec, Hondata) vs. what I grew up tuning (HSABs, IABs, IFRs, main jets, dist springs/weights) since '85), better cold-start, transition, etc. but it seems like a $2K-$3K beta test when all parts are considered and there are this many issues people are still seeing in the field.
Thanks again for the collective wisdom. You guys are the best.