yeah, another exhaust combo thread. deal with it.

[johnunit]

framework:

Somewhat tight budget (would like to keep it under 600ish for parts)
Sound and smog are both a concern. A lack of muffling or de-emissioning can both get me towed under "street racing" laws here. Air pump must be there too.
No drone on the highway, medium volume under heavy throttle
best power possible within those restrictions without custom fabrication



351W swap headers
mint original 90 mustang H-pipe including cats and air tubes
mufflers to fit (18 inch offset/offset? Magnaflows?)
Impala tails
MKVII O2 sensors


What muffler size do I need? Is there anything way off about that setup? Will the h-pipe be a big restriction point? Am I missing anything that should be bashing me over the head with the weight of it's own obviousness?
It's expensive, but does anyone have any experience/knowledge of these?
http://www.summitracing.com/parts/WLK-17156/

I'm about to finally have some money to blow on the car, and I wanna get it right.

[85crownHPP]

What size pipe is a stock H-pipe??

Why not go aftermarket with-cats H-pipe?

You're going to need something for mid-pipes, yes on the offset/offset, and you need whatever size muffler you need to mate to whatever size tailpipes and mid-pipes you get.
And I wouldn't like the idea of a flapper valve inside my muffler...

I think the size/length of the tailpipes and size of any trumpet shaped tips has the most to do with how loud its going to be...
You cant hear mine idling inside the car, and its not loud enough to offend when she's going somewhere.

[johnunit]

What size pipe is a stock H-pipe??

Why not go aftermarket with-cats H-pipe?
You're going to need something for mid-pipes, yes on the offset/offset, and you need whatever size muffler you need to mate to whatever size tailpipes and mid-pipes you get.

stock fox body, I have no idea and was sorta hoping to find out (should have been clearer) but I am 99% sure I have 2 inch right now, factory or stock replacements.

Aftermarket catted H-pipes seem to be 400-600 dollars here. If I'm not gonna completely torpedo my performance, I'd like to turn that into 140ish by going with the h-pipe a guy has for sale. Before someone asks, I'm not going with what I have now because I have multiple small un-findable leaks and it's ancient.


Help me out here, what would I need for mid pipes?

[85crownHPP]

Whaaaaat I swear I saw catted H-pipes on eBay for under 300...!

Some folks used fox mid pipes with extensions, some have used the Walker 43281 2 1/4" pipes, or whatever its 2 1/2" equivalent is.

Really the stock stuff shouldn't hurt you too bad. If an Impala SS can make 200 some horsepower out of 2" tailpipes, so can we.

It's hard to do "budget" and "right" in the same go. You can always upgrade later too.

[351m]

Measure the OD of the pipe, that will be the size. Probably 2.25" for the Mustang H pipe though as the walker midpipes I have seen listed on here are 2.25" as well.

Doing it right and the easy way would be this...

- Find out what size the H pipe is, buy mufflers to fit.
- Buy Impala tails and weld the outlets of the mufflers to them after they are installed.
- Install the catted H pipe and hook up the air tubes
- Drive to a shop and have the remainder of the pipe bent and installed.

[johnunit]

[QUOTE=85crownHPP;578485]Whaaaaat I swear I saw catted H-pipes on eBay for under 300...![quote]

I have too, but shipping is ridiculous to Canada. Shipping + duty + exchange rate brings it over 400 pretty quickly.

Some folks used fox mid pipes with extensions, some have used the Walker 43281 2 1/4" pipes, or whatever its 2 1/2" equivalent is.

This is good to know. given that, I may just buy everything but the tips from the guy with the mustang H-pipe.

Really the stock stuff shouldn't hurt you too bad. If an Impala SS can make 200 some horsepower out of 2" tailpipes, so can we.

It's hard to do "budget" and "right" in the same go. You can always upgrade later too.

fair enough, but my plans are for a bit more than 200hp, and I'd prefer to not have to rip into new and nearly impossible to re-sell stuff once heads, cam, etc. are done. Flow-through 2 1/4 inch mufflers along with the Walker 2 1/2 impale tails and the stuff discussed here should support plenty though.

I wouldn't be so anal about getting the package right, but I don't have anywhere better than an increasingly cold and dark driveway to test-fit stuff, and I know most of the original hardware is going to fight whoever touches it every step of the way. Having my ride to work held at the exhaust shop because it costs 200 bucks in random parts or labour that I don't have would be a bit of an issue.

[Lincolnmania]

i use mustang 2.5" midpipes and weld extension pipe to them.......2.5" ofset ofset mufflers

[85crownHPP]

the stock H-pipe might be a bit tight if you are planning for more towards 300 HP then

[johnunit]

Thanks mangs.

Revised plan:

BBK 351 swap headers
Stock mustang H-pipe (but plan to upgrade around the time heads, cam, whatever go in)
Mustang 2.5 midpipes
whatever extension shop needs to make the next 2 fit right
Mufflers 2.5 off/off length doesn't matter within reason
Impala 2.5 tails

[Pirate]

Muffler suggestions:

1. Flowmaster Delta 50 series.

2. Walker Dynomax Super Hemi Turbo (longer version).

Or get the Magnaflows.

Just a note, none of these three will last more than a few years with cats in front of them under moderate to heavy daily driving. The only long-lasting muffler (that will last for any length of time after catalytic convertors) that springs to mind is a Borla.

[1990LTD]

Why won't they last with cats in front of them?


I like my Magnaflows without converters, FWIW

[Pirate]

Why won't they last with cats in front of them?


I like my Magnaflows without converters, FWIW

Because, in addition to converting spent gases to carbon dioxide and water....they also spew out a bit of sulfuric acid (I hope that's teh correct type, I've slept since then), but of course, that's the dirty little secret of catalytic convertors.....

[1990LTD]

Right-o. Unburnt hydrocarbons ftw.

[351m]

Muffler suggestions:

1. Flowmaster Delta 50 series.

2. Walker Dynomax Super Hemi Turbo (longer version).

Or get the Magnaflows.

Just a note, none of these three will last more than a few years with cats in front of them under moderate to heavy daily driving. The only long-lasting muffler (that will last for any length of time after catalytic convertors) that springs to mind is a Borla.

So Stainless will but Stainless won't last in short?

[1987cp]

Muffler suggestions:

1. Flowmaster Delta 50 series.

2. Walker Dynomax Super Hemi Turbo (longer version).

Or get the Magnaflows.

Just a note, none of these three will last more than a few years with cats in front of them under moderate to heavy daily driving. The only long-lasting muffler (that will last for any length of time after catalytic convertors) that springs to mind is a Borla.

Regular Walkers are more nicer to the ears.