At first I was going to lean towards the SD, but seeing as you're in Troy, you'll want to consider two things...1) Pick the less rusty of the two. 2) See if the SD has enough pick up for you to get on to the I75 & Big Beaver Rd. (Exit 69) without concern for your safety.
If it were in FL I'd go for the SD, or a newer 300E. (If you're afraid of busting knuckles in the cold harsh nasty winters of Mi. while adjusting valves, there are guidelines for adjusting them warm.)
-Larry