I now have 160* t- stat that auto zone said was for a lt1 , well it's not . it's for a sbc 350 , I have had this one for about a year . could this cause any tuning problems? like running rich+ when it's cold the heater does not work very well

 

What kind of coolant temps are you seeing during cold weather driving? If the coolant isn't getting hot enough (120-140degF) it could keep the PCM from going into closed loop. And it will richen the mixture, in effect compensating for a "cold start".

Shoebox's page has a picture of the differences between the two t'stats.... its possible the SBC Gen 1 t'stat is not blocking off the water pump bypass....

Shoebox's t'stat comparo

 

well I think its going in to closed loop( I have a a/f ratio gauge and after about 5 to 7 min the o2 's start cross counting) the temp gets to 160 to 170 , takes a long time to get there.