My friend has a brand new 160 degree thermostat for an LS1 that he will just give to me. I always thought that they would fit because the LS1 stat is one big piece including the elbow and housing and I thought the LT1 is just the thermostat itself. I just took mine out and it looks pretty much exactly like an LS1 stat as in its just one piece. Can an LS1 stat fit an LT1?

 

The LS1 is "conventional" flow cooling, vs. "reverse" cooling in the LT1. Rob/Shoebox has a photo on his site comparing the two types of t'stats. You might want to look at that picture. If the LS1 piece looks the same as the LT1, its hard to understand why they only sell them with a complete "housing" for about $60.

And, if an LS1 'stat will interchange, you will have a lot of fun, because even a stock 195deg LS1 'stat can be shimmed to open at lower temperatures - a popular "free mod" for the LS1's.

 

I can't be sure, but I don't think you can interchange them.