On a stock 350 , you can gain 20 to 30 horses with a set of long tube headers.How much do you think you'd get with a set of block huggers? They are not much longer than a set of manifolds.

5-15 maybe ?

20-23 is probably high on a stock engine. But it depends on what you have to start with.From a single exhaust with y pipe and one muffler you may get that much.From a dual exhaust with 2.25 or 2.5 pipes with good mufflers 5-15 as Doug said.

Shorty headers will make about the same peak HP as a good full leanght, but will not make the same mid rpm power as a full length.

http://www.sandersonheaders.com/letsgettech3.htm

Originally posted by BPOS:
http://www.sandersonheaders.com/letsgettech3.htm looks like a good article...but hp and tq cross at 5252 rpms....NOT 5500 rpms...

so right from the gate that chart is incorrect.

Well aint that something. Youd think they might know something about that, building high performance engine parts and all. That graph sure aint from any real dyno testing.

I think they are supposed to cross at 5250...but maybee I remember wrong...

I will be installing my new ceramic coated 1&5/8" Summit full length headers soon. I already have dual 2&1/2" exhaust to the mufflers and 2&1/4" out of the mufflers. I don't know if I'm being overly optimistic but, I'm hoping to pick up 20HP....

-Mark

Yeah, by golly, that chart is kinda screwy - I noticed that the torque values on the right don't line up with the HP values on the left...

Originally posted by kristofer:
</font><blockquote>quote:</font><hr />Originally posted by BPOS:
http://www.sandersonheaders.com/letsgettech3.htm looks like a good article...but hp and tq cross at 5252 rpms....NOT 5500 rpms...

so right from the gate that chart is incorrect. </font>[/QUOTE]I think it is the vertical scale throwing things off. ;)

http://www.sandersonheaders.com/images/smallvslargetubechart.gif

Horsepower is a mathematical function of Torque. The formula is: Hp=Torque X RPMs / 5250. a That is why, of necessity, at 5250 RPMs, Torque equals Horsepower.

Lynn Bilodeau

Ah, I see. It is the vertical chart and the fact that the numbers arent to the same scale that makes that chart look wrong. Even though the graph crosses at 5500 on that chart, horsepower isnt equal at 5500. By that chart, toruqe looks like it is about 490 at 5500rpm, and horsepower looks like it is about 515 or so. Thats actually the way its supposed to be. If you look at the individual curve at 5250, horsepower and torque actually is equal due to the fact that the left side of the graph isnt actually equal to the right. That makes me feel a little better about the integrity of that chart(I guess we shoulda looked a little more closely).

Originally posted by greg moreira:
Well aint that something. Youd think they might know something about that, building high performance engine parts and all. That graph sure aint from any real dyno testing. It is probably from actual data points in testing different headers then plotted.