[JLMounce]

Originally Posted by Squidward

I will check around with local chassis dyno shops. There are a few in my area. That seems like a better time/money investment than piles of trips to the strip. Thanks to you and others for the suggestion. I like what you provided about the methodical approach. I tried the idle afr adjustment. I got slight changes in vacuum, but it was pretty much ranging from 13-14" even as I adjusted idle afr target from 13.5 to 13.1, to 13.8. I finally settled on 13.4.

I was at the strip Sunday. I got 4 passes in before I called it good enough. I didn't want to break my car when I had a 25+ mile drive back home. I got data logs, too.

My street timing has 16*/36* timing, with 15* vac advance. I started my first run at 16/36, and put in a [email protected].

Next run I bumped timing by 2* to 18/38, which has almost always been good for a tenth and a mph or so. Instead, I got [email protected] (wrong direction)

3rd run I pulled the 2* back out, and changed WOT afr's from 12.2 to 12.1. I got a [email protected]. Half track mph was up 76.01 vs 73.66 from previous run. All of these runs were pretty much hot lapped, first run at 1051 am, and the last at 1110 am. All runs were 10 minutes apart.

My 4th run had no changes because I had to choose a dial-in for the trophy bracket race. I ran a [email protected]. I got knocked out by a guy who is waaay better at racing than I am. He competes in NHRA class racing, with a 301 turbo car that runs 12's. He had a lot of room to toy with me, much like a cat with a mouse. He cut a better light by .3, and I was slower vs. index by .2. So I made it real easy for him to tap the brakes just before crossing the finish line.

What cam are you running in the car? For what it's worth, my idle AFR is set at 14.1 and I run my WOT fueling closer to 13:1.

General rule of thumb is leaner will produce more power. Based on what you're saying here, it sounds like you may currently be at optimal spark advance. Might focus instead on fueling.

Have you run any logs of your runs? Running logs for the pass and comparing specifically intake air temp and the resulting cylinder temp can help equalize runs where you may be losing power simply to added heat if you're hot-lapping.

One more thought here. If you replaced a poorly tuned carb with the FiTech, it's possible that you may be increasing combustion efficiency by way of proper fueling and better spark control. It's not out of the question, that reducing timing may increase power as a result.