Here is a view from the rear driver's side of the engine. Here you can clearly see the fabricated throttle linkage setup I have. They're just a few scrap pieces of 1/4 inch aluminum. I have a Lokar cable threaded through the bottom and the spring attached at the top. This setup did not work well with the Lokar cable because the cable bound inside the sheath from the heat from the headers. I went to Pep Boys and bought a much cheaper vinyl cable. It was much more flexible than the Lokar cable and shorter too. So I threaded it over the top instead of the bottom and have been running happily ever after since. My carb is the 500 cfm Edelbrock. It's a pretty good match with the 292 - a little bit rich out of the box. The 292 is .060 over for 301 CI. Cam is a little hotter than stock (.464I & .490E lift - 194I & 204E at .050) but the pistons are stock. So I'm sure the 600 cfm will be a bit too much for your 250 in stock form.
The adapter plate I bought from Tom Langdon came with screws. And they don't intefere with the adapter. They're low profile, flat top screws. They actually recess just beneath the surface of the plate.
The worst part about my throttle setup now is that I don't have enough cable travel distance to open the secondaries or set the automatic choke. But I have enough acceleration for my needs. The 292 spins the tires with very little effort. Lots of fun. If you're ever in metro ATL let me know and I'll show you my setup.
-magic mike-
