These are full length/long tube headers design for 3rd gen F bodies. They have 1.5" primaries and 2.5" collectors but the best thing is that they follow the factory routing path! All you'd need to do is have a Y pipe fabbed up and you can have longtubes and stay legal with the cat/s in their stock location. These would be great for 305 and some 350 engines depending on how high hp they are.

 

i think those are more like mid-lengths. i wouldn't run 1.5" primaries/2.5" collector if someone paid me. the 1 5/8" is more beneficiary (sp?) to even the smallest output 305's than the 1.5's

 

28" length primaries,same as the other long tubes. I was under the impression that the 1 5/8" primaries were just a tad large for a 305 but since that was the standard that's what we got. I'll be doing more research on this.

 

The stock or mildly modified 305 does not respond well to tube diameters larger than 1.5" and you'll see a definite decrease in overall power. If you have modified the car to run in the 12 second range then 1 5/8" primaries become necessary. But a larger than 1.5" primary will cause a decrease in power in a 305. A 350 can tolerate a 1.625" primary but try to avoid the temptation to go larger on a street engine. One of the few manufacturers that make an equal length street header for the 305/350 is Hooker under part number 2138. Tube diameter is 1.5" while length is 28-30" specifically for street use because the stock engine runs out of breath around 5000 rpm. The shorter tube length in designed to help the engine breath better in this range. A 12" collector extension can be used to broaden the torque curve with these headers. The Hooker unit is a traditional 4 into 1 header with the left side connecting with the right side,therefore facilitating connection with the rest of the cars exhaust system.
Quoted from "Camaro & Firebird Performance Handbook" by Peter C. Sessler and published by Motorbooks International.

 

I was just looking through my PAW catalog a couple of hours ago and saw those listed. I was wondering why nobody ever mentioned those on this board.... until I saw this thread.