1 1/2 or 1 5/8?

[5oh4fun]

I was wondering if there is a big difference in power between shortie headers? My engine is stoch with the typical mods: CAI, cat back, 75mm MAF, underdrive pullies, and 3.73's. I don't know that it will make that much of a difference. Thanks for any help.

 

[RacEoHolic330]

If you're gonna buy new headers, don't even bother with 1 1/2". You'll get much more out of the 1 5/8" with room to grow.

 

[drgn5.0]

agreed

 

[maverick0716]

On a stock engine the 1 1/2" headers will make the same if not more than the 1 5/8s. But if you plan on modifying the car more (h/c/i) than the 1 5/8 are the way to go.

 

[04sleeper]

I put 1 1/2 inch equal length shorties on my car and lost 4 hp and 3 ft lbs.
Also tried 1 5/8 inch shorties and lost 5 hp and 6 ft lbs. Went back to the stock headers and picked up the HP again. I would wait until you get some heads before you get the headers. They will just hurt you for now.

 

[tmoss]

I put 1 1/2 inch equal length shorties on my car and lost 4 hp and 3 ft lbs. Also tried 1 5/8 inch shorties and lost 5 hp and 6 ft lbs. Went back to the stock headers and picked up the HP again. I would wait until you get some heads before you get the headers. They will just hurt you for now.

And the TRUTH will set you freeee............

 

[90mustangGT]

I'm not a fan of equal length shorties, they tend to loose bottom end with no real gain over standard shorties, plus the other issues, nevermind.

A 1 1/2" runner won't flow as much maximum airflow as a 1 5/8" runner, but the velosity in the 1 1/2" runner will be higher. Your setup won't max out the flow of the 1 1/2" shorties, but you will get more volosity out of them which will mean more power down low.

Unless you have replaced the factory H pipe with thier old style cats with at least a 2 cat midpipe, your better off with the stockers.

If your going to replace both the headers and midpipe, I wouldn't even think about shorties of any kind, just get longtubes.

 

[cleanLX]

I would not spend the money to put aftermarket shorties on a stock motor.
Long tubes on the otherhand...