At 09:39 AM 5/11/2004 -0500, you wrote:

Tracy has (I think) shown that airflow velocity apparently plays a major role in producing power.  His runners are 1.25 and 1.5" in dia - so clearly not oversized.  This creates higher air velocity in the runners which in turn can cram more air into the chamber when the port opens (the momentum effect of the moving air)  
 
When I combined my primary and secondary runner, I ensured that the total area of the single tube did not exceed the combined area of both primary and secondary tubes in the attempt to keep the airflow velocity the same as in the Mazda.
 
 
As always, thanks for the comments Ed.  The intake idea that I stole <g> uses 1.75" tubes.  This is certainly not larger than the combination of Tracy's tubes, but that could be a problem in itself, particularly because it's so long.   
 
I've been looking at U-bend aluminum tubing at Burns Stainless, and trying to figure the best way to make this into a usable intake.  Do you have a picture or drawing of the inside of your molded chamber? 
 
Also, can you (or anyone else) refresh my memory on what's supposed to be the best simple, single barrel TB?  I'm thinking it was a mustang, or Corvette part, and I even think there was someone trying to sell one recently on the list.  If you still have it, let me know.  I would want something light, simple, and with no injectors built in.  Basically, just a butterfly on a flange. 
 
Thanks,
Rusty (intake #3 scheming has begun) 

Rusty,
The guy with the LS1 throttle body was probably me.  It is from the Ls1 Chevy pickup, not a Corvette.  So, I think it is smaller than 75mm.  I'm thinking that its 70mm, but I would have to measure it to be sure.  It is easy to strip down to the basic body and throttle plate, and has been modified for a/c use by changing return springs so that it stays open when at rest, rather than closing to idle.  I've attached a picture (if it doesn't get stripped off).

Mark S.