gt40 or gt40 P - Which are better if want to keep smog?

[Triple White 91]

Which heads are better to maintain smog and with an edelbrock performer intake?

 

[Maryland Stang]

The P heads are not drilled for smog. The regular 40's are ready to go.

 

[LiquidGT]

To my surprise Explorer GT40s arent drilled for smog, I would know, but I passed my final emssions test with high flow cats. I didnt have the thermactor system hooked up to the back of the heads because there is no provision for the pipe.

I dont know if you have to have an inspection though, if my state had inspections I would've JB welded the pipe to the heads.

 

[Maryland Stang]

I just drilled holes in the thermactor pipe so I could mount it to the back of the heads. We have visual inspection only and I've already been to the test station and they said it was good to go.