June 2004 Remember to reset the float a bit LOWER than the original specs (about 1/64"- 1/32"). The modern gas isn't as dense as the old stuff- so the floats don't "float" like they should... this will often percolate over into the manifold on a hot shut-down (flooding the engine). This has always helped the cars I've worked on... including Stromberg WW's(2bbl), WCFB's and AFB's...RF ------------ June 2005 Figured 90 plus heat is a good time to do some tuning. I've learned that if you can get them to run decent in hot and humid weather chances are it'll run great when it cools down a little. I might have busted an urban myth that the reason the temperature goes up on an Avanti is hot air trapped under the hood. I spent some time driving with the hood popped to see if there would be any change in running temp. None that I could see, not the slightest change on the gage...and the gage was up there today. I've spent lots of energy on dialing in my carb and timing because I changed to an Edelbrock and a window style Delco distributor. Because of the changes I wasn't sure why the car would lay flat at the very top of first gear at full throttle. I had resigned myself to believing the setting on the TV cable for the 700R4 was the culprit. My logic was based on the fact that if I adjusted it to shift a little sooner the engine wouldn't hit the RPM range where the problem occurred. I need to make this very long story short...the problem wasn't timing or the trans adjustment but the air valve in the Edelbrock carb! The air valve keeps the engine from stumbling from an overabundance of fuel and air when the engine is not ready to accept it. Well, I started thinking that I eliminated the choke valve to keep it from closing under boost so why not see if the air valve might not be forced in the closed position by boost also. It was easy enough to experiment. I took one of he stakes that held the strings of an old volley ball net and bent it to hold the valve open a little. The eye of the stake went over the carb stud, I bolted it down and checked to make sure there was no interference to the throttle blades. The car pulls smoothly all the way op to 5,000 without the power drop at the top no bogs either. I cured a flat spot on light acceleration by adjusting the vacuum advance to react quicker. The Delco window allows the use of some GM performance products but even for the stock setup the vacuum advance is critical to proper driveability. The vacuum advance won't affect full throttle acceleration but if your car feels like it's holding back when you give it a little gas around town check the vacuum advance. Tuesday it gets a professionally built exhaust system. I'm getting rid of the JC Whitney mufflers because the baffles keep coming loose inside the muffler! I forget what muffler was targeted for my car. Choices are a little limited because of the way the exhaust pipe needs to routed around the bigger GM trans. They will be adding an "H" crossover. My experience has been that the "H" evens out the sound and quiets the exhaust some. The trick will be putting it in a spot that I can still get the trans pan down and the leak from the rear main doesn't drip right on it :>). Ernie R2 R5388 --------------- I need to have the headpipes run below the frame not through it. The standard length mufflers would then require a very sharp bend upwards to mate with a std. length muffler. The "H" will go right at the front of the trans pan but not as far forward as the fly wheel. I don't care for the sound of glasspacks at full throttle and some turbo mufflers drone at low rpm. I'm hoping the new mufflers don't drone, I have two new stainless Flowmasters that were $100 apiece in the garage that I took off my GP because I couldn't take the drone. The GP is a little different because it has an "X" rather than an "H". The "X" changes the exhaust not drastically. I replace them with a couple $15 Summit Turbo mufflers that sound great and seem to perform as well. I would have put Summit Turbos on the Avanti but they don't show them with 2" openings. If you don't mind I'll share the air valve discussion with everyone. You've shared some things with me before that I'm sure everyone would have found interesting. First, the std AFB doesn't have an air valve only the Edelbrock or modern Carters. And, if you are naturally aspirated there wouldn't be an issue either. The valve is weighted to stay shut until the engine can pull enough air to pull it open. It will only open as far as engine demand will let it. The secondaries themselves open fully through a mechanical action. All I did was use the equivalent of very stiff wire to hold the valve partially open. Since the valve is weighted to stay shut I figured that it was possible that enough boost could keep it shut. But held partially open my thought was that it would move in the open direction under boost. It's possible that the car would run OK without it but in the colder weather I think it would bog until it was really warmed up. I have the heat riser passage blocked and no choke already.