I think that the stock ones are not that good, but i can't switch to headers because of the law in our country.
Are there manifolds out there that fit our car and flow better?
I've seen the sanderson manifolds and the dont look like headers at the first look, so i think these would pass vehicle inspection.
Or does GM perf.parts have something good in stock?

Thanks for the help

Pat

 

Edelbrock T.E.S they look like headers but replace stock manifolds, they are tubualr exhaust systems

 

TES does not replace the manifolds. It replaces the exhaust up to the cat. They would be called "headers" by those who don't want you taking off the factory exhaust system.

If we're talking about the '91 TPI, you have about the best they had. You could take them off and clean/open them up a little to improve flow. I know a guy who did that and produced some respectible power with them.

The factory y-pipe is a significant restriction. If you can replace that with a mandrel-bent part, that would help performance.

Do you have a dual cat version? Those are decent as well.

 

Yes, '91 Z28 with dual cat.

Whats different to the earlier manifolds?

Pat

 

TES does replace the manifolds, what are you talking aBout? They replace the stock factory manifolds and they have all the emissions stuff on them and they are 50 state legal in the USA. They are not headers, they are basically redesigned manifolds.

 

Dope: They don't replace the factory manifolds because they don't hook up to the factory y-pipe. They are installed in place of manifolds,and y-pipe - true. But, they are not a bolt-in replacement for manifolds - unless you use the TES y-pipe.

However, Pat specifically said he cannot remove the manifolds because of the laws in his country. That's not the United States, in case you hadn't gathered that, so being 50-state US legal is irrelavent.

They are headers in the common use of the term on this board, and as defined in gear-head magazines, and amoung all the gear-heads with whom I associate. You're trying to narrow the defination to suit your tastes - good luck. When you get right down to it, what we call "headers" are "manifolds" in the broader defination, and vice-versa. So, let's stick to convention. And what may help the person asking the question.

Pat, back to your question: The difference between dual- and single-cat wasn't in the manifolds, but the pipe/pipes to the cat/cats. I wasn't clear on that in my earlier response. There is some improvement to be made with cleaner bends in the pipes between the manifolds and the cats. If you're limited to factory manifolds, cleaning/opening up what you have with a die grinder, and smoothly-bent pipes, is about all you'll be able to do.

 

Would they know the difference if, maybe you switched to better factory manifolds from a different car? The manifolds shaped that were used on the 350's in the '70s were a better design than what these cars came with. They were as close to headers as you can get from the factory, but they were stock Camaro parts (as well as trucks and other cars) from the '60s to the '80s.

This is a picture of a set that looks the same, but does not have provisions for the AIR tubes. Almost any set like this that you find will have the holes for the AIR tubes, however.

 

Corvette ram horns would be your best choice for exhaust manifolds if you're not allowed to use headers. There is also a guy out there named Brezenski that I think makes stock style looking monifolds that have very good flow. Basically all the guy makes is cheater parts for racecars.

 

Actually, I just found this out the other day looking at my uncles Corvette...

His '84 Cross Fire Corvette has factory headers that have all the emitions on them.

If it just has to be a factory manifold, get those.

 

Hey thanks all

I will check if i can get some of those! :lala:

Pat