Hi,
New to this forum and joined since during my recent searched, I found many references to McCulloch s/c s and hoped to get help here.

I have two old Fords; an original 32 roadster with a built 59A, Columbia rear and Lincoln Zephyr gears in a 39 transmission. I also have a 40 Ford convert with ahem, ahem ..  a SBC. I first thought about putting the VS-57 on the 32 but it is running too well now and space under the hood is congested so the s/c is going on my 40. Have a few bikes too!

I have a rebuilt VS-57 done by CUNDN Racing in Texas, idler arm with new spring and a Kaiser bracket and a Holley 1450 650CFM with mechanical secondaries.

The McCulloch bracket that would work is a CH-101 but can't find one so I'll be making my own from carbon steel.
Ar setup issue I'm wondering  on is how much the idler arm pulley and spring should be deflected to have the proper load on the belt?

If the load is too small, the belt won't be pushed down into the solenoid actuated supercharger head unit. The pulley there has a solenoid operated system that increase the gap and thus the effective pulley diameter, to speed the head unit RPM up for boost. If the load is too high, it will force open the head unit pulleys and always run in boost.

If anyone here has a VS57 could you please tell me what the pin to pin dimension is compressed on a functioning installation please? This will help me in setup and belt length.

Thanks,
Glenn