OK I am going to upgrade to larger injectors. My question is more on the MAF I guess. I know thesensor has to be calibrated for the injector size but does the MAF housing have to be changed also? I already have a C+L 75mm MAF with 24lb injectors but when I put in the 42lb's do I have to change the whole housing or just the sensor part itself?

Since you have the C&L MAF its really simple to fix. Theres replacable sampling tubes to go inside your MAF housing itself, they come in diffrent colors for diffrent size inj. Heres a link to C&L Hope this helps ya.. http://www.cnlperformance.com/calibration.html LUK

Sample tube

i'm not 100% sure but I think that they calibrate the sensor for the injector and the size of the MAF. when you get your calibration sheet, it gives the injector size and MAF size that it was calibrated for.

Do people not ever see my posts?? its like i always hear an echo..

Matt dont complicate it any, the term "calibration" which in this sence simply means the housing itself typically C&L MAFs) are tricking the sensor..theres nothing magicaly being done to the sensor electronicaly.

Thank you for correcting me. Yes, i did just look over your post as if it was never there. Sorry...

What is the case fora ProM 77 mass air meter. can i just change sample tube?

you are right, the word calibration does complicate things.

Matt that comment was ment for stang8689 btw.

Far as Pro-M im not so sure there as easy to change like that, best bet would be contact them to see whats involved in changing yours.

No, the C&L's are one of a kind MAF. They have interchangeable sample tubes, and you use the stock electronics.

A Pro-M MAF has a fixed sample tube, and uses their own electronics. In order to change injectors and keep the same MAF (With the Pro-M) you must either buy a new MAF "calibrated" for your new injectors, or send the MAF into Pro-M to get it re-calibrated.