Yep, I believe my driveshaft when running a small block chevy, th350, D300 was 13"-13.5". Very short driveshaft, but I never had any issues with it.
434 pump gas SBC with an NX/HVH plate system
th350/Coan 5,000 converter/Dana 300 tcase
Dana 30 front with 4.56's/Dana 44 rear with 4.88's