OEM exhaust flow, headers to H pipe

[krtw]

Ok, here is another question for you all..... I am planning to swap heads, etc and was considering full length headers to catted H pipe. Just curious what kind of flow is possible with our stock exhaust. Heads I am considering are anything from GT40x to AFR, have not made my mind up forsure.

Personally I think its really cool that our cars came with real headers, not cast manifolds. When I first bought my car and checked out the OEM exhaust setup I was impressed....the first car I ever had with true dual exhaust from the factory. Previous car was an '89 V8 camaro, stock exhaust on that car was a joke.

Food for thought...

 

[JJ95GTID]

I had the same thoughts when I bought my car. And for stock setup it is definately a good setup.

I ended up replacing each part of the exhaust seperately as money permitted.

The most hp gain is from replacing the 4-catted H-pipe. It is really restrictive compared to aftermarket 2.5" H and X pipes with or without cats.

When you step up to aftermarket heads then the headers are the logical next step. If you look closely at the stock headers the are crimped to make access to the bolts easier. This is a restriction on aftermarket heads with larger exhaust ports.

The catback is really a matter a choice of sound and $$$$.

 

[final5-0]

Yes ... OEM mid pipe is the most restrictive item :Word:

Yes ... While it is true our OEM exhaust does not have cast iron manifolds

IMHO ... Calling them real headers is being very optimistic

They have the same issue as a shorty header
No benefit of exhaust gas pulse scavenging

You get that benefit only from LT's

However ... For a mild bolt on combo ... OEM headers don't hold you
back much ... if the truth be told

Now ... As for catbacks ............
They are one of the worst gain for buck spent items
you will get involved with when talking power besides ignition upgrades

You gotta be moving a good bit of air before a catback makes any
difference ... Again ... Talking Power NOT Sound

Grady