Not to argue, but
My old 750DP has no 4 corner idle, and it worked fine on my 292/508/108 purple cam, with just a bit of secondary cracking. I tried drilling the plates, increasing the hole-size in small steps,and closing up those secondaries, and after a bit,it ran about the same.
The same carb/same engine, but with a 270/280/110 Hughes cam; well she liked the secondaries shut up tight, and I had to close those pesky holes.
The same carb/same engine but now with a 276/286/110 Hughes cam, the carb is exactly the same with just a tiny bit of secondary cracking.
All three cams were initially set up with timing in the range of 12 to 16 degrees.I currently run 14*, with the 276 cam.
I tried a 750 Vacuum secondary, but I couldn't wait for the secondaries to open; I'm impatient that way,lol. With the DP I can stomp it at pretty much any speed below 55 at almost any reasonable rpm, and light up the tires.The Vsec wouldn't do that, no matter what spring was in there.I like tirespin!
I also tried a 600Vsec.As compared to the 750 DP,that was like loosing two cylinders.The only good thing I can say about that bad-boy, is that it is possible to lean it out pretty far and get some really fantastic miles per gallon,lol.
But,I think my cylinder pressure is up around 175psi(aluminum heads)
