Exhaust System *"X" or "H" pipes??

[Kevin-D]

Im getting a new exhaust on my 66 from the headers back. I was wondering if I should go with the "X" pipe cross over or the "H" pipe cross over... Or would I even need it? I dont plan on racing the car.. Im getting flowmasters, (two chamber) with 2.5 in. pipe, but the guy said the "X" pipe is the way to go. What if I went with 3 inch pipe then woud I even have to use the cross over? Or is 3 inch too big? Does anyone have 3 inch pipe? I figured I would ask you guys on the board.. After all.... You guys ARE GTO Legends... Please give me your opinions! See everyone on the 11th!

Kevin D
1966 GTO

[GTO_AL]

Get the xXx pipe that makes the roof blow off and then you can parachute out of it onto a boat.
Hehehehehe, the X pipe is better and you can't get 3" because it would sound better than mine LOL, I'll have to get the 3 1/2" for the '66 LOL, oh wait, that exhaust is good already.
Enjoy the meeting on the 11th, I'll be in Oregon. Tell'em all hi for me.

[THOR]

Hi Kevin,
There are many others that have lots more experience than I do but I just went thru this whole issue with my '70. In my opinion, and in the opinion of some exhaust professionals, unless you're racing, the 2.5 inch pipe along with "H" crossover is fine and easier to put in or to have installed(if you're thinking Dr. Gas X pipe at least)

I went with the torque tech brand pre bent aluminized mandrel bent downpipes and tail pipes, 2.5 inch diameter pipe and walker dynomax ultra flow mufflers thru stock quad tips on the back. The Torque Tech brand headpipes didn't fit my RAIII manifolds as well as I thought they would and the headpipes didn't "nest" up under the trans crossmember contours as well as I'd hoped. As a result, I have a tad less ground clearance than before. The flow is excellent though.
Having a new exhaust system is grrrreat ;D
Good luck with the project 8)

[Kevin-D]

well thanks Alan, but the xXx pipes make flames come up thru the motor hood too.. I DONT need that. I just waxed it. ;D

[G6T8O]

Hey Bruce .... How does it sound ??
Does it sound as good as Botkins Yellow SLUG ? ;)

Bill P. *8)

[G6T8O]

Kevin ..

Is the engine built at all ? If it's stock A 2.5" to the muffler and 2.25 out the back with an H-pipe would be A good system .....

Bill P. 8)

[REED_RACING]

I would go 2.5, 3 inch is over kill unless the motor is built. I like the Dr X crossover. I currently run the 3 inch Torque Tech system with 3 chamber Flows. The 2 chamber Flows will be louder than 3, but Brad B says my 3 chambers are louder than his 2's. I think a lot of the sound will be determined by the horsepower being put out. There's my 2 cents.... ;D

[THOR]

Yo Mr. Bill :P
Sounds pretty danged good but it's quieter than the old glasspacks that were on there when I first brought my car down to Bison's. That's good. The neighbors around my rented garage (including one little hottie) were hassling me and wondering if I was gonna get "a new muffler".
No...It doesn't sound quite like Bob's car

[G6T8O]

Hey Bruce ...
I'm lookin forward to hearin it. Will this new system change with the idea's your kickin around ??

Bill P. 8)

[theJUDGE]

Well to add what's already been said, my 68 GTO has 3" w/ 2 chamber Flowmasters. (sets off car alarms, knocks stuff off the walls & loosens interior parts). As R.R. stated, overkill for a streetcar, especially if you ever want to have a member of the female persuasion ride in the car.
The Judge is running 2.5" w/ 2 chamber Flowmasters through factory splitters. (doesn't sound quite as pissed off) but sounds wicked. I would recommend the 2.5" aluminized pipe running through either 2 or 3 chamber Flowmasters, the 3 chamber will definately sound less raspy with a stock engine.

[REED_RACING]

And there you go! ;D

[G6T8O]

Your Honor .....
You missed the part about the crossover !!!!

Bill P. 8)

[Pontiacshack]

NO,NO,NO, this isn't going to work! You must first have Davey build you a 700 hp engine, then go with 3 inch to the x pipe, and 3 1/2 out the back. That's what you should really do. Okay, now I'll try to get a bit helpful. If you go with the H pipe, you will save a bit of money, and it will tuck up higher to give better gound clearance than the X pipe. That has been my experience anyway. 2 1/2 inch w/H pipe and some good mufflers,( I really like the sound and performance of Magna flow mufflers), and I think you will be very pleased. Good luck.

[Kevin-D]

Thanks for all your comments and ideas. Now I know a little more when I do go to the muffler shop. Once again, Im glad Im a part of the Legends Forum. You guys are GTO Gods!

See everyone on the 11th. ;D


Kevin D
1966 GTO

[Flyingtiger]

Hi Kevin, A short note on your exhaust. X crossover would be more efficient therefore the best choice, however, you'll loose the accessibility to your drive shaft and/or transmission unless you install ball joints immediatly after the "90" on the down pipe, and slip joints just before the mufflers. I'm currently doing this same job on my '65. Be sure you'll have enough room for the drive shaft to clear regardless of rear axel spring height. 2.5" is the way to go. Dynomax is the best muffler for the application. Consider having the aluminized steel system built for the car, as I have had to compromise some clearances with the Flomaster "one size fits all" A body kit. If I had to do over again, this is the route I'd take. Also, there's an outfit in Pacific Wa. that specializes in these types of performance installations. Their name is Performance Exhaust. Give them a call and talk to Andy Collins. Phone number for PE is 253-891-2939. They do quality work at a reasonable price. Tell Andy you heard about him from the club. These guys will treat you right.

[Kevin-D]

OK thanks! I'll call them now.

Kevin D

[G6T8O]

Can any body tell me what the hp/gm there would be between the two crossovers, On a stock engine ??

Bill P. *8)

[Pontiacshack]

Hey now, I'm not trying to step on any toes here, but I am no longer recommending the exhaust shop mentioned a few posts ago. The ownership changed, and the last person I sent there, got bent over pretty good. I think we have a pretty powerful tool here, so I'm not trying to abuse it, but I would check with Mark D and get the name of his exhaust man. Just my two cents, good luck.

[LonnieS]

Thanks for stepping in with some caution, Stefan. You got our back, 'G' ;)

[THOR]

One other thing on exhaust...man lotta posts on this ;D
I got the CD with 54 different tracks of exhaust combinations, professionally recorded. With it comes a list of flow rates
This was done by a man named Hand. 27 3 inch pipe recordings, 27 2.5 inch recordings, half with X pipe, half with no crossover at all. It's fun to listen to. I will bring it to the next club meeting

[theJUDGE]

Well the exhaust shop that I recommend now that Brock sold out is American Exhaust in Renton.
Kevin is a true craftsman & he has done Ainsworth's Judge, Bruce's Judge, & is doing all of MIKE-D's work.
Anyway, the original discussion is in the archive postings for the phone number, but they're in the Sunset part of Renton.

[THOR]

Hi Mark,
What time is that demo? ;D
I'm there

[ponsteen]

Hi guys! FYI I have ran both two /three chamber Flowmasters as well as Dyno Max mufflers. I have also ran H and X pipe systems.

I am currently running a three inch Dr Gas X system with Spin Tech mufflers in my 64 wagon. For those of you unfamiliar with Spin Tech mufflers--they are currently being run by Nascar/Nascar truck/Outlaw sprint cars/Busch/and various roundy round cars. The tone is somewhat similar to Flowmasters but they do not drone as badly as Flowmasters. Blake can bring them in at Honest Perf. Spin Techs are less money than Flowmasters as well!! Check prices at the Sprint Shop (1-800-664/2788), there are several series available.

The X system gives a definite high pitch sound. Listen to D. Kennedys' 65, or my wagon.

A quality mnuffler shop should have no problem installing an X/H system. Ask first and find someone who knows what they are doing. Any system should be installed with the headers being the lowest point in the exhaust system. Anotherwords the system should run uphill as it approaches the rear end and the mufflers should be as far back as possible.


The bottom line is any system should sound good on a Pontiac. ::)

[G6T8O]

Mr. Ponsteen...
With your experience with both system's, Was there a noticable difference between the two? Would it make a difference on a stock engine?
Thanx
Bill P. 8)

[ponsteen]

Hi. The only difference I could detect in the systems was the sound. The X system emits a higher pitch.

The only performance test that I am aware of was conducted by Jim Hand using his 71 Pont wagon with a 455 which runs in the high 11's (probably faster now). Hand tested approx 12 ;Dmufflers and both X/H systems. The tests concluded the X system was superior, (meaning his car ran faster with the X system using the same muffler as the H system), and the muffler of choice was the Dyno Max 17749 (Hemi Turbo. But his tests were measuring performance in the quarter, noise decibels, ets. It's very interesting.

Does either system pick up a stock motors' performance? Definitely yes! The sound of either system is worth at least 40 Horsepower---Just listen and you be the judge.
;D

[THOR]

I have the flow rates for all the muffler and pipe and crossover tests done by Jim Hand. When one buys the
Silent Power CD with the 54 different exhaust system recordings, the flow rates are also provided. The Walker Dynomax line indeed had the best flow. I picked up the UltraFlow SS mufflers based on this and the fact that it's about ten decibels lower than the other mufflers at about 3500 rpm. With these mufflers that hottie won't tattle on the landlord about that "loud car" ;)
Since it's copyrighted material, I can't publish it but I can show it to ya at the next meeting 8)

[MikeS]

Kevin, I realize this is a little late, But, Hot Rod Magazine ran a test on this very subject comparing both 3" X pipe and 3" H pipe systems. I don't remember which month it was, but it was a 2002 edition. The outcome was that the X pipe system gave a little more horsepower through about 5600 RPM (10 -15). The test was done on what else, but a Chev 350 (good ol' Hot Rod) and Flowmaster 2 chambers. The test mule was some car, (probably a Camero,) hooked up to a dyno. The motor was a medium build up, but very streetable. Unless you are gonna build a hot motor, the X pipe won't be worth the clearence headache you'll get for your 15 HP investment. H pipe that 389! Just my very late 2 cents!

[Kevin-D]

No your not too late Mike, Thanks to all of you for your help. This board is the greatest thing for guys like me just starting off.. I will be going with 2.5 inch aluminized pipe with an H pipe with Flow Masters. (two chamber) I wanted to go with an X pipe but since I dont really plan on racing.. An H pipe will do the job for me. Now for the next discussion... ;D HEADERS!! What type is good? What type has a nice fit for a 389? I dont want to pull the engine to put them on. I have Hooker Headers now.. and was under my car the other day and noticed that one had dragged the ground and was patched up. Im gonna try to have it fixed. IF there is a fix for it.. But I should do this all at once while Im there. Save money in the long run...

Thanks
Kevin D

[REED_RACING]

Where do we start with Header installation? Headers are not fun to put on a GTO. I have 1 3/4 Hooker super comps. I know for a fact I have jack the motor on each side for installation. Also have to take the oil filter off too, but they sound sweet...... ;D

[Icelander]

The Pontiac Street Performance website has been talking about this lately as well. The concensus I got from them is that Hookers tend to fit moderately well, but nobody has had consistent fit on their A-bodies. Some rage at all the modifications they had to do and some won't buy anything else. As I understand it Hooker just bought themselves back a few years ago (like Harley Davidson did from AMF) so their quality is improving.

Just my $.02

Kendall

[Pontiacshack]

I purchased a pair of Hedmann Hustler headers because of the claim that they are a super fit. Well, other than a couple of holes in the flange needing some opening up, they really fit great. These were for a round port, but I believe they also come in a D-port. They are not cheap, and don't get them confused with the standard Hedmanns, because I understand they don't fit very well at all. Good luck, and remember, it's only money! ;D

[MikeS]

Kevin, I have a set of Hookers as well. Blake says they fit the best of what's available over the counter, but they're definately not perfect. Blake is in our club and the owner of Honest performance in Renton. Give them a call.

[455RamAir]

Just a quick re-visit to the X/H pipe subject. A friend of mine runs a 580 HP 455 with 2" primary headers, 3" full exhaust, Super Turbos and H pipe. He doesnt like the sound with the X pipe. Not deep or rumbly enough for him. I think it sounds pretty good but I can appreciate what he's saying.

I've heard many people say not to run an X pipe with chambered style mufflers because the sound is less than optimal. Apprarently the X favors straight through's like Magnaflow and others.

Todd