The C & L plenum w/ Accufab 70MM TB fits fine for me (I also have the Mac CAI). The rubber boots are pretty flexible - I don't think you'll have any problem with a 75MM.
Someone on here has to have a 75MM T/B & Mac CAI???
I hope it does fit cuz I want to order it today. Maybe they have a tech ph# I can call that won't actually try to sell me some other kit instead. I like my Mac CAI & hope I can run a 75 mm TB w/ C&L Plenum up to it's all.
I have the C&L Plenum, BBK 70MM throttle body, and MAC CAI. The setup works great, and there is a real nice performance increase. The only problem I could see with using a 75MM throttle body will be the blue sleeve from the CAI being too small in diameter. But I think MAC sells larger sleeves, so it isn't anything major. Hope this helps.
So you don't think that sleeve will work? That was my concern. I don't want to have to try to contact Mac to get a bigger sleeve; maybe I can do something else. I also don't want to order it & then not be able to use it cuz I don't have the sleeve.
It's not a big deal to call Mac and get another sleeve - the sleeve that comes with it should work, though - it's very flexible & 5 MM diameter isn't THAT big of a difference.
When I rotated the MAF on mine I called Mac and ordered a sleeve to connect the two pieces after cutting the tube. They shipped it right away and I paid like $12 for it. Again, the sleeve that comes with it should work fine, though.
Okay, here's some better info. Yes, the stock TB is 65MM. I just had my Mac CAI off (changed fuel injectors & MAF). I paid careful attention to how the CAI went back over the T/B. I believe the sleeve will fit over a 75MM T/B, HOWEVER, you may run out of slack in the clamp. I realized that I was down on the last few notches on the clamp and it just slid over the T/B & sleeve...
So, there you have it - looks like the sleeve will fit (with some persuasion, but the clamp MAY be a bit small).