Its been a while since I updated this. Over the winter I removed the swirl port heads and flat tappet cam. I replaced them with Jegs crappy imported vortec heads and a baby 196 duration Chevy 14097395 cam. The idea was not a race car, but more grunt where I needed it for towing a 5000 lb trailer with a 5000lb van. The heads are a long story, but they will do. The cam I can't say enough good about for towing. It required a re-tune on the chip, but it tows a lot better. The left fuel table is the stock one the right is what the engine requires fuel wise with the new setup. The crappy low end on the left is now a big hump in volumetric efficiency, more air and fuel at low rpm, but I don't have to floor it all the time, so it works out gas mileage wise. All this is a few months old and the fuel table is more refined now.
After all that I couldn't have it dumping through the rusted exhaust so I bought a few stainless sections from summit and did a budget exhaust that should last a while.
The before and after dyno sheets Dyno Dynamics does not calibrate their readings as high as the USA made Dynojet, the comparison HP is what is close to the DJ numbers. The columns are in different orders on each sheet, and I started the "after" pulls at a lot lower rpm to see if I lost anything down low. A 40hp gain on the top and a 50ft lb torque gain across the whole torque curve made a big difference. The engine still tops out at about the same RPM and that's fine. I don't run it above 4000 when towing anyway, mostly in the 1800 to 4000 range. I did some more work on the fuel curve since these runs were made, but have not put it back on the dyno. Its still breathing through cast iron manifolds and the factory TBI. It still idles, runs and sounds like stock, but in the way GM should have done it instead of how it came off the assembly line.