The vacuum advance for "window type" Studebaker Delcos will physically interchange with most 1950s-1970s GM vehicles. For that vast range of application, there were originally at least 25 different part numbers, with important differences in the operational specs; primarily, vacuum required for full advance, and total degrees of advance. However, vacuum advance technology ceased in the 1970s and has became almost forgotten technology. So now days, VAs have became a one size fits all, as long as it physically fits. The one size fits all for GM vehicles is Echlin #VC680, which is readily available at FLAPS for $10-15, and is also referenced on this NG as a replacement for Studes. It is also the same one I removed from a Stude distributor a couple days ago.
The problem is, the Stude VA is supposed to advance 16 degrees at 12 inches' vacuum, but the VC680 only advances 12 degrees, and requires 16-18 inches' vacuum to do so. So that vac advance will almost certainly result in lost pep and MPG in a Stude. In researching VA specs on-line, the closest to Stude I found was VC1812, which advances 12 degrees at 12-14 inches' vacuum. With that VA on a Stude, the 2 degrees' less advance could be offset by advancing the timing a couple of degrees.
I found a better answer at Summit, with an adjustable VA, made by Accel. A couple of other companies also make the adjustables. Will report more when I receive it.
Bottom line, for anyone running a window type Delco in a Stude, if you are not satisfied with MPG or pep, the VA is a good place to look when it comes to troubleshooting.
The problem is, the Stude VA is supposed to advance 16 degrees at 12 inches' vacuum, but the VC680 only advances 12 degrees, and requires 16-18 inches' vacuum to do so. So that vac advance will almost certainly result in lost pep and MPG in a Stude. In researching VA specs on-line, the closest to Stude I found was VC1812, which advances 12 degrees at 12-14 inches' vacuum. With that VA on a Stude, the 2 degrees' less advance could be offset by advancing the timing a couple of degrees.
I found a better answer at Summit, with an adjustable VA, made by Accel. A couple of other companies also make the adjustables. Will report more when I receive it.
Bottom line, for anyone running a window type Delco in a Stude, if you are not satisfied with MPG or pep, the VA is a good place to look when it comes to troubleshooting.
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