To things off I had a set of spare 241's laying around. They were ported & polished milled .030 along with a 5 angle valve job. I also went with a smaller compressed thickness gasket to help bump compression to 11.0:1. I'm using 7.350 pushrods with this set up. I still have my stock cam in it for now. Anyways after the swap I checked all ground wires and connections. Everything looked good. I also put an off road midpipe on it and ported my factory air box and throttle body on my 04 GTO. At first I was getting a DTC for random misfires took care of it when I went back over my rocker arms but got a MAF code as well. I tried cleaning it. I'm going to take the car to get it tuned but I need to get it running less rough first and dont know where to start. How can a simple head change throw so much off & I havent even put in a cam yet.

 

Unplug the MAF.

 

You DCR is probably really high with using the very small stock cam with the high SCR, so you probably have to much timing advance now.

 

Thanks, This is exactly why I didnt put a cam in it yet & was going to do each mod piece by piece, in fear that the car would run like complete crap & I wouldnt be able to make the trip to get it tuned. Guess playing it safe backfired this time.

 

The stock cam has very low DCR. Still, your timing probably is too high. If you'd put a better cam in, you would have likely had the same issues

 

Which MAF code are you getting?