632C2

I decided to put an 'X' pipe on my '67 convertible this past weekend. The motor is 383" and is based on a ZZ383 short block. I bought the 'X' pipe from Dr.Gas. Since I have exhaust manifolds on the car, Dr.Gas was a little apprehensive as to whether the power would go up on the car. They said that typically 'X' pipes on a motor with cast iron exhaust manifolds doesn't make much of a power difference.

I am glad to report that they were wrong! I realize they have to be careful with their claims. I picked up almost 9 rwhp and over 20 rwtq at their respective peaks. What I think is more significant is the increase of between 15 and 20 rwhp in the midrange! To say this 'X' pipe works is an understatement!

These numbers are SAE corrected. Uncorrected numbers are 402.57 rwhp and 427.81 rwtq. Standard corrected numbers are 400.96 rwhp and 425.58 rwtq.

Here is the dyno chart and a pic of what the 'X' pipe looks like on the car.





Steve

73, Dark Blue 454

Interesting,..plus x-pipes mellow out the sound.

Did the X-pipe get in the way of any of he e-brake cables/brackets? Did re-locate anything or simply put the X-pipe under it?

632C2

It did not get in the way of anything but I wouldn't say that it was a simple installation. It took me 2 days to accomplish it.

Steve

CoolKars

Nice installation. Are those 2 1/2" pipes, if so, will V-band flanges fit through crossmember. What is the outside diameter of flanges. Thanks for post, I was considering x-pipe but after seeing dyno result will definitely put x-pipe on when installing new exhaust system.

CGGorman

632C2

They are 2-1/2" pipes and, yes, the V-band flange will fit through the crossmember. I don't have the actual OD of the flange.

Steve

Brettmc

Any idea what difference placement has on the effect? For instance, putting the X under the differential.

Brett

rcread

I have an H pipe. Would you mind dynoing your car with one of those too? Thanks.

632C2

I don't have any concrete results on placement. According to Dr.Gas, the farther forward the 'X' is placed, the better. My guess is that since the velocity slows down the farther back you get, the effectiveness might diminish the further back the 'X' is placed.

You're joking, right?

Steve

rcread

Yes. Though it would be interesting to see how much of an advantage the X pipe is over the H.

SULLY_PA

ROTFL

427Hotrod

You DO realize Steve that there are folks around here with built Big Blocks that don't make 400 RWHP!!!

Thanks for the info...very interesting test!!

When are we going to the track?


JIM

ZL1powr

Great results...That is a potent 383...

Maine Vette

That's pretty interesting stuff Thanks for the post!

427Hotrod

Hey Maine Vette....we have a Forum Member in New Hampshire who is wanting to come down with his 540" '67 Vette to the Forum Cruise IN in Bowling Green in a few weeks. His buddy who was going to bring his car too wussed out and can't come. You have any plans of coming down for it? Y'all could run together to make sure everyone got there with no issues.


JIM

632C2

Thanks, Jim. Depending on the weather, I am planning on going to the track next Wednesday night. Up here, you never can plan too far ahead. Have fun at the Cruise-In!

ZL1powr and Maine Vette: Thanks!

Steve

CheezMoe

Hi Steve,

Is there a particular spec you ordered from Dr. Gas, or do you call them and tell them the application?

thanks

rihwoods

When in doubt,go "X" and "H"...

632C2

I used their universal 2-1/2" 'X' pipe. It was around $100.00. I talked to Chuck.

Steve

SLVRSHRK

Did you order it direct? Looks ,like they want around $179 for that pipe on their website.

Thanks