To upgrade intake manifold on not?

If I were going to change it, I would use an Edelbrock AirGap RPM. Spring and fall won’t be a problem for you. I drive my car year round with an AirGap RPM and don’t have any issues. In the winter it’s not uncommon for it to be in the upper 30’s when I fire my car off to go to work. It might take a little bit longer to warm up, but it’s really not that much of a difference compared to an intake with a heat exchanger.

But you probably won’t notice much of a difference on a street car/cruiser. I probably wouldn’t even bother changing it to anything other than the AirGap RPM unless you happen to have a regular performer rpm just laying around.

As for the TTI shorties, if you’re looking for more clearance under the hood you won’t get it. They’ll improve your ground clearance quite a bit compared t the Hedman long tubes because they stay about the steering linkage. But they’ll still be tight to everything in the engine compartment. I bought a set of TTI shorties to put on my Duster to improved the ground clearance compared to my Doug’s long tubes. They saved a little bit of ground clearance, but they had just as many tight spots and clearance issues as the Doug’s. Just different ones. So I ended up putting the Doug’s back on. I’ll put the TTI’s on my Dart when the engine goes back in it.

My install of the TTI’s is here in my build thread My "new" '74 Duster- or why I need a project like a hole in the head