if I were to remove the egr plate from under the carb on my 1981 351m and replaced it with a riser plate would this cause engine problems or perfomce problems? and if I did this is there more to it then just removing this part of the emmisions would I have to block anything else off. ?

 

I disabled the EGR on mine, and experienced some pinging. To cure it, I went up a couple sizes on the carb jets. I'm running #60's in it now. The jets are easy to change, if necessary.

Other than possible pinging, it won't cause any other problems. Make sure you have the vacuum line plugged.