Just a curiousity thread, the LT4 Fbodies were 50 state smog legal. But their Exhaust manifolds didn't have AIR tubes on them. So how would one go about getting around the visual when getting smog checked?

 

I thought after producing the first few cars with stainless steel stock style manifolds, they switched to stock cast iron manifolds that had been extrude honed???

 

From what I understand they all got the stainless steel extrude honed manifolds. Just with the different cam they no longer used the EGR and therefor didn't have AIR tubes. Thats just what Ive always.

 

AIR and EGR are two different systems. They have absolutely NOTHING to do with each other. The LT4 in the Corvette got away without the EGR system, because of the cam overlap. That's a single connection from the #8 primary to the back of the intake manifold that is deleted. But the AIR system is used to help the cats heat up faster on startup, and connects close to the front of the exhaust manifolds. That can't be deleted just because of the cam change. I know the Corvette LT4 engines had the complete AIR system.

Check this thread:

https://www.camaroz28.com/forums/sho...d.php?t=494581

 

Yeah I read that about an hour ago. Ive been looking online to get clear pics of the Fbody manifolds, but only found the one on here for sale a month or two ago and the a port of one in Car Craft of the 30th Ann. SS.

I didn't understand the logic where I got that info from either. Like I said, I was just searching google like mad for any thing I could get.

 

A friend of mine with a 30th Z28 bought a set of AS&M dual-cat headers. They were terrible - melted everything in the engine compartment, even though we used liberal amount of heat blanket everywhere. He pulled the AS&M's, called his buddy, a manager at SLP, and got a set of the extrude honed manifolds for the LT4. I think this was around 2002. They were just like the stock manifolds. I haven't seen him or his car in many years, or I'd get a picture.

 

I've got a pair of those manifolds laying in my garage, I'll try to get you some pics up after church.

 

Yeah please post up some pics.

As for the manifolds, they say they flow as good as shorty headers. For what they are, I think they are kinda cool actually. They look stock, flow like shorties, easy install, 50 state carb legal. Wish I could find a set someday.

 

 

Appears they have the connections for the AIR pipes and for the EGR.

 

I saw that too. That answers my question.