mdjice

I just got a set of headers (hedman elite), a set of super 40s flowmaster installed on my 77 vette (350/290 HP) I asked for the H pipe system and they installed the mufflers straight telling me that if they did the H pipe, they would have had to weild it and i couldn t access my tranny easily and would have to cut the pipes...is this true? also is it really worth it to do the H pipes or not? they will do it for free if i want to so. should i do it or is it a jus more tim without my car for very little ??
thanks

Gordonm

Get an H pipe installed and have them put in a ball and socket joint. I have this on mine and it comes apart very easily. I have had my exhaust off more times than I care to remember. I'll see if I have a picture of it.

Here it is with the two clamps undone. There are 3 studs tha tgo in the holes and you just tighten them up. It breaks apart quite easily.


Another better shot of it together.

Tonys96

No, it won't do anything for you.

Gordonm

It will cut down on the drone quite a bit. Evens out the exhaust pulses for a more pleasant tone. Performance wise proably not much

MN80Vette

I just switched from block huggers without an H-pipe to full length ceramics with an H-pipe, so I had a pretty good without/with test. I recommend an H-pipe. The sound is smoother and more even left-to-right. Someone on this CF recommended this site to learn more:

http://www.popularhotrodding.com/eng...xh/index1.html

Here's a picture of where my new exhause from header ends to H-pipe.

73383

You can put the H pipe in now or later, but you will probably end up doing it after you listen to the drone those flow 40s put out at 2000 rpm.

big_G

My H-pipe helped chill the '40's quite a bit. Still a little resonance around 1,500 rpm, but much subdued.

mdjice

if it s only a sound issu I actually won t need it! My super 40s sound perfect!!! not too loud indside the cabine but loud asd hell outside it s perfec!! rememebr I got the super 40s not the original ones! so if the H is only a sound issu I won t bother if it affect performances at lower Rpm then I will

Little Mouse

I think you should go back to the stock exhaust you are causing
noise pollution.

mdjice

Yeahhhhh RIIIIIIIGHT!!!! loooool
Thanks a million times little mouse for all your precious help!!! Sounds great and works wonders even not timed and carb tuned yet!

Little Mouse

Sounds like the mufflers you picked were what you were hoping for,
did the headers fit good ??

MN80Vette

No, sound is not the only reason for an H-pipe. The Exhaust Science link I posted above is long and detailed, but you can mine the performance benefits of an H-pipe or X-crossover from the article.

Ganey

The purpose of the balance pipe is to improve performance. The resonance issue is a side benefit.

hayman

I wish I knew what this drone/resonance sound you guys are talking about.

I just installed a Edelbock intake and I asked the question if I should block off the cross over and the majority said to block it. Wouldn't this cross over in the head have the same effect?

I have not been exposed to the high performance stuff so I must have got lucky with selecting the Dynamax ultra flows because I hear nothing but a nice sounding rumble.

Bill

mdjice

can you still take out your tranny without cutting the H pipe??

MN80Vette

I don't know and I won't be concerned about that until I have enough Corvette funds to install a Keisler 5-speed. I had the Super T-10 completely rebuilt two years ago.

mdjice

How much did it cost you to get the T rebuilt if you don t mind me asking

75coupered

H and X will improve flow and performance by reducing resonance in the exhaust pulse, good upgrade on any exhaust system, the sound benefit will also shine through.

Best bet it to install a split H pipe with a connector flange bridging the two sides, this will allow you to insert a block-off plate between them and effectively eliminate the H for testing purposes. One downside to all H and X pipes is that you eliminate telltale signs of problems on either bank of the engine, oil burning for example, the puff of smoke will exit both pipes instead of just the affected side...thus the blocking plate for testing and tuning helps to isolate each bank of the engine/exhaust, plus this will also allow you to remove just one side of your exhaust for work without having to take it all out.

panic

this is how it sounds at idle a 2 3/4 undercarriage exhaust with 3'' X pipe and 40' flomasters under a 570hp vette



and some pics...

Jims79

good choice you don't need the H pipe. I was going to install one on my modified 79 and my buddy bobs77vet said "have you heard your car coming around the block". I stood in his driveway while he took a few laps and man bobo is dead on the thing sounds sweet.