How much does temperature affect motor?

70 Buster 340 said
Since I still haven't heard if the manifold was new or not....

I'll take a guess

it runs shitty cold cause of that choke 'setting' and runs shitty hot because of a vacuum leak with a strong possibility of manifold/head seating/sealing issue since it was recently swapped on to a good running engine.

Sorry I thought I said in a previous post. The manifold was not new, it came with my dart on another running engine. When I swapped to my current engine, I literally took the motor out of the motorhome, swapped oil pans, changed all the freeze plugs, painted it, moved my accessories and aluminum intake over then dropped it on. Otherwise the engine was not opened in any other way. As far as vacuum leaks, I just got back from getting it nice and hot then spraying around all possible vacuum leak locations (alls hoses, carb base gasket, intake gasket where the manifold meets the head, china wall, and even around where the heads meet the block where I could reach.) The engine did not react at all so I am going to assume no vacuum leaks.
The way the choke is currently "set up" is that it sits at that angle when off and as soon as the engine fires up and has the smallest bit of vacuum, the choke gets pulled open all the way. Since its true that I basically dont use it. I will be removing the flap all together to help eliminate variables.
I dont think it runs too shitty cold all things considered. I figured any carbuerated engine running no choke would not be running ideally while cold until the carb got a little heat in it to help atomize the fuel. On start up, I have to feather the throttle for about 30ish seconds or else it sputters out and almost dies. As soon as the carb gets that little bit of heat in it then it can at least hold idle and drive around slowly until it really gets up to temp.