General Use Recommendations

Answers for your questions
(and in case you have any doubts on the performance impact of our exhausts)

General use recommendations based on restoration objectives:

Purist type Restoration - If you are restoring a car to its original state - without modifications to the engine beyond that which was provided by the factory....then our exact reproductions are what we would recommend in most cases. Stock pipe size in virtually all the high horse Pontiacs was 2.25".

The early GTOs (64-66) and later Firebirds/TAs (after '74) didn't have a performance option that used factory headers. These cars gain a substantial performance improvement by upgrading to our factory headers while retaining an original appearance.

Modified Restoration ("Restification") and unlimited Modified - If restoring or improving a vehicle with a performance bias....i.e cyl head improvements, intake & carb upgrades our enhanced flow/larger collector version headers and larger pipes and crossover are for you.

Comparison of RARE's 2.5" version Ram Air header (right with ceramic silver)
vs. original RAIV factory header collector (left, pn 9799721  2.09"i.d.). 

Think factory style headers are still too restrictive or power limiting?

Here's one example of how efficient they are in turning your car into a Torque monster and by delivering the same power improvement that a tube header does for any street/strip Poncho (without the tube header "blues"......clearance probs, ticky-noisy, burning gaskets, rust thru, crunched tubes, unable to get to all needed bolts, floor heat, etc.)

A recent dyno test of a 455 + .030 with single 4bbl, Crower cam and ported heads using our 2.5" collector Ram Air series headers & 30" of 2.5" pipe produced 517.2hp @ 5600 rpm, 607.0 ft lbs @ 3800 rpm.

(And if you see Greg Jones in his 70 GTO Conv, with this powerhouse between the fenders, get ready to breathe tire particulate.)

Ultimate exhaust systems available for all A-bodies, B-bodies and F-Bodies

General use recommendations based on Horsepower/Torque objectives:

Below 400HP(Stock power profile): Usually for stock restorations or for improving the performance of non-modified stock engines our "stock configuration" or standard factory headers are highly effective and recommended for these applications. 
Greater than 400HP: For all engines with modifications and ambitious power goals, our larger-collector/enhanced flow factory headers are recommended. Our enhanced flow versions are the 2.5" Ram Air series headers for all GTOs/LM and 2nd generation FBs...and …the enhanced flow headers for the 1st generation FBs, X bodies and Big Cars are our "Super" Long Branch. 

To extract the most power from your Poncho you should finish your exhaust system with our 2.5" or greater sized pipes and an X-crossover. 
All these components together make up our "Ultimate" exhaust system.