ok I have given in and decided my plenum seal is bad. So would there be any advantage of going to the m1 intake? How difficult would this swap be? Does this eliminate the plenum lower plate? Oh btw its a 99 1500 with a stock 5.9 automatic thanks

 

I go if you have an M1 go for it but you can do a manifold mod (other posts) while you are in there (I didn't wish I had)and replacing the pan gasket isn't that bad (other post for that too) did mine about 6 months ago. Instructions on forum are good.

 

From what I understand you simply install the manifold and efi adapter to use your throttle body.

 

I opted to keep everything stock this time might try it out later when funding is better.