arodenhiser

First some quick background....

1968 Cutlass S
350 sbo with small valve 5 heads
9~9.5:1 C Ratio
650 Holley carb on Edel Performer (soon to be a '70 bbo Qjet)
True duel exhaust, 2 1/4 inch from header to to tips, rear cut out bumper.

I have just replaced my rotted out headers and need new collectors welded to the tail pipe side. My headers have 2.5" collectors with the 3 bolt flange. I am having new 2.5" collectors welded to my exhaust side on monday.

Is it benificial to have the exhaust shop put in a 2.5" diameter H-pipe in at this time. I am being quoted about $125 extra (parts and labour) to put in the H-pipe over the price to just install the collectors.

In a year or two/three I plan to replace the exhaust with a complete 2.5" system.

Where is the best position for an H-pipe. Is it better to have it closer to the engine or does it not matter. I am thinking it should be behind the crossmember so it will not be in the way of the tranny mount etc.

What are the experts thoughts?

Whew, all this typing has me exhausted!

Adam

arodenhiser

Wow! It must be slow here to go a day without an opinion. TTT

Adam

Rickman48

Had a 396 BB Chevelle 2-dr wagon, and a crossover seemed to enhance responsiveness and increase MPG.
$150 for a crossover seems real high - call around!
On the same car, I had collector 12" extensions installed - really made a difference you could feel!!
Eventually ran mid 13's @ 110 MPH, with stock convertor and 3:55's.

Beob

$100 sounds good! Installing a F-Master H pipe kit now.

455man

I agree it sounds expensive. If it could be done cheaper I'd do it for the extra hp.

Redog

"X" pipe is the best, followed by "H" pipe, then true duals.

"X" pipe helps equalize the pressure from the left and right bank better than an "H" pipe and is dyno proven to make more horsepower than both an "H" and true duals

Plus "X" pipe give you better sound.

True that an "X" is going to be the best for drag and racing apps, but IMHO is does very well on a street car too

455man

I'd read that the H pipe gives an increase in torque and the X gives more hp.

GAOldsman

Either way is a great safety feature to keep you from catapulting if the front u-joint gave way at a high speeds (drive-shaft safety loop alternative) if placed in the vicinity halfway or closer to the tranny. Although often enough you get what you pay for and $125.00 installed is not too too much, unless you have a shop with a lift, welder, tubing bender, etc...
Scot

HouTXCutlass

I bought an entire Dynomax 2.5" exhaust system with an H pipe section already in it for about $240, installed it myself and had a muffler shop weld it up for $50. That was 8 welds and about 45 minutes of shop labor which they charge $60 an hour labor rate. $125 seems a little high especially if they're doing other exhaust work. What is their labor rate? My H pipe is about 18" behind the header collector connection but I don't know what the optimal placement is. Good luck, Rob

cutlassefi

According to Hedman Headers who makes both, an H pipe gives you more torque below peak, an X pipe typically gives you more hp above peak.

Depending on your gear, if it's numerically higher than 3.73 then I'd do an X pipe, for anything lower than that an H-pipe would be my choice.

Jmo.

Redog

I don't think exhaust tubing is going to stop a driveshaft

Lalo442

Summit has this Kit for $34.95 for 2.25 inch pipe like mine but they have other sizes I was thinking if getting this then getting it welded or maybe just letting the muffler shop do the whole thing ???

http://www.summitracing.com/parts/SUM-642022/?rtype=10

UnkleMarc455

I've had both on a 1972 Cutlass Supreme w/ 350 combo and the H pipe felt better. It was a street driver and I actually like the H- pipe sound better (JMO) find someone with both set ups & compare for yourself. I was running 2.5 Torque Tech exhaust systems.

ziff396

Well, I completley redid my new magnaflow with the X pipe to true duals, and hooker aerochambers. I hated the sound of the X. To ricey for me. Sounded more like a new mustang I am running 3" x 2' scavenger pipes into the rest of my 2.5" magnaflow pipe system with 12" (8" case) cherry bomb 2.5" all the way through resonators just before the trumpets. Now I have the LOW big block sound that I like Did I notice any difference between the x and duals? NO. Scavenger pipes are old school and work great for torque and the sound I prefer. And, I run her up to 6k. (sometimes) JMO

arodenhiser

I got my collector's welded on today. I decided not to go with the H or X pipe today. My exitsting exhaust will last me another year or 2. When it finally needs to be replaced I will certainly use a kit with one.

http://www.youtube.com/watch?v=Nu4KSe3l2zw

Here is a short video of her after getting welded up with the new headers.

Just a reminder... 350sbo, true dual, Hookold 3901 Comp Headers with 2 1/2" collectors and 2 1/4" exhaust/tail pipes through unknown mufflers and factory tips.

The vidoe is a little raspier than with the naked ears. I do like the steam shooting towards the camera.

Adam

Don L/442

Sounds good. I'd be happy with that for a year or two.

jag1886

I put an H pipe in my car with the new exhaust system they help bottom end torq and they help cut down on the drone from the mufflers. A local muffler shop will convert your exhaust to and H pipe for way less than people are quoting here.