Smog Legal.....
Thread Starter
Melting Slicks
Joined: May 2006
Posts: 3,385
Likes: 4
From: King George VA
Smog Legal.....
Does anyone have trouble passing smog or inspection with a 383 LT1? Is it the cam or the extra displacement that makes it fail? Will a combo of a small cam and Long tubes top it over? Really I just wanna know what doest it take to go fast and stay inspections legal?
Le Mans Master
Joined: Oct 2004
Posts: 7,706
Likes: 485
From: Everett WA
C4 of Year Finalist (appearance mods) 2019
It will pass with long tubes on provided that you run cats right after the collectors and you run the car for a good hour prior to the inspection. The cam may make a difference but Tom Wong or Brads custom auto can help you.
Melting Slicks
Joined: Mar 2002
Posts: 3,106
Likes: 126
From: S.L.C. UT
The cubes won't hurt your emissions, it's cam choice you have to be careful with. I have run 224/230 on a 112 lobe sep, on several 383's I have built with no problems passing emissions. I have heard of some guys running upwards of 230 duration on a 114 lobe sep passing. I haven't rolled the dice on an engine that has to pass emissions to try something that big. I think it gets "ify" when you go beyond about 224 intake duration on a 112 lobe sep, or tried to close the lobe sep below 112 with that much duration.
