[mgarblik]

I have some results to share concerning multiple dyno sessions I have had to squeeze in between classes and all kinds of other problems and distractions over the past couple weeks. Between parts getting lost by USPS for 2 weeks, endless problems with the dyno, printers specifically, and other distractions too numerous to list. I have been able to get 26 power pulls on the engine and get it tuned decently for now. I will consolidate the useful information, try to get it in a format I can post and put it up in the next week. These are my broad takeaways for what it's worth. 1. My overall engine package had too many compromises that were made necessary by not wanting to wait for years for the proper parts to be available. 2. This package needed more compression, round port exhaust and better exhaust manifolds/headers. 3. The bathtub intake wants lots and lots of fuel. 4. AFB carburetors are very, very sensitive to what is happening above the airhorn. Will flat out not run properly with an air hat on the top. I have seen this with some Q-jets as well. 5. Long branch, D-port, iron manifolds are crap on a serious performance engine with large displacement. They are just too small.

Now for some numbers: Best with exhaust manifolds, 464.6 Ft. Lbs @ 4700 rpm Peak HP 442.2 @ 5900 rpm. With borrowed 1 3/4 headers from a 74 GTO NHRA stocker: 18" long 3" collector, 481.6 ft. lbs torque @ 4800 rpm. 20-28 more ft. lbs. of torque everywhere. 448.4 HP @ 5800 rpm. Was not tuned to the headers, so 10-15 HP more on top could be expected. No reason to tune to headers because they are not going to be used.

So I have presented the basic results. Since I have no ego to care about, it is what it is. Overall a frustrating, humbling experience. Sometimes, you just get a reality check when having to make so many compromises for the lousy pump gas, the fitment in the chassis, (exhaust manifiolds), and the super cool looks, bathtub intake and original looking AFB carbs with tiny air filters.
On the plus side, excellent idle quality, starts quick and easy, snappy throttle response, seems like it will have excellent street manners. Anticipate using lots of gas. It runs best at 12.4-12.7 AFR everywhere. Starts to run lousy leaner than 13.2-13.4 AFR. It loves fuel.

Going to put it in the car and drive it around through the fall here in Ohio. We have a chassis dyno at the school, so in the spring, I may try to do some tuning on the chassis dyno. That's more real world and the AFB carburetors can operate in their real world environment. That will be chapter 2. We will see how it runs on the street next.