Talking Temps...
if I remember correctly, the stock t-stat in the D2 was a 204 degree (fully open). Back when I was into 'em. supposedly a t-stat out of aTD5 was a direct replacement (don't hold me to it). that said, I ended up getting the Motorad 439-180. that alone dropped temps all the way around. the down side was winter time.. a littler longer to warm up. Was also running the Hayden 2991 fan clutch. had to walla the holes in the fan housing a smidgen to bolt it on. down side was, you could hear the fan till it warmed up (winter time and a hundred yards). That combo worked great..
I see Hayden now has a complete deal. Part # 6352 (fan and clutch).