Hi all. I purchased a muffler from a 914world vendor and wanted to get a second or third opinion on the fit. I have a 1972 tail shifter and the muffler is hitting the cone at the end of the transmission even before tightening down the bolts. See image below for reference. Also, above the muffler you can see the GT muffler mount. With the bolts snug I still have about 1/4" gap between the bracket and muffler.

I've corrected the assembly of my engine mounts so I don't think that's causing the clearance issue; I'm using the 911 mounts with the concave washers. Is there anything else I'd need to check assembly wise? The vendor says it'll be fine to snug it down and have a divot in the muffler. Which I'm fine with. But my OCD kicked in and it's making me wonder if I don't have something else upstream put together incorrectly.

In the image below hopefully you can see cone touching the muffler in the back ground.

Is something off, or would tightening it down and having the transmission end touching the muffler be fine?

Thanks in advance!

Click to view attachment

Do not force the fit. This is clearly an issue between fitment on a side shift vs tail shift.

@Van b

Should I dimple the muffler for the clearance?

It's it a bursch muffler?

@TheCabinetmaker

It's from Ben's (mb911) SS muffler final production run last year.

this is one of the reasons the stock 2.0 and six mufflers are "banana" shaped to help clear the trans end/nose...on a 911 that's where the shift rod comes out..also the 911 mounts are a little shorter thank the 914 mounts pulling the whole assembly up at an angle making the muffler even closer...use the new 914 six mounts...I've found that the the GT muffler mount adds to the problem....the fix is to use longer mount studs with spacers to move it to the rear
what headers are you using

Heat exchangers must match up to appropriate exhaust (e.g., 1.7 HE's to 1.7 muffler) even if the HE's will basically fit any engine.

Are you sure that's a 1.7L muffler? It sure looks like my 2.0.

FWIW, do NOT put too much stress on those GT exhaust hangers. They will break and potentially cause you problems. Ask me how I know.

@johnhora
It has 2.0 heatexchangers. Do they make spacers or is this a fab job? I'm assuming +-1/2" SS spacer with gaskets on both sides, yes?

@BeatNavy
That is correct, they are 2.0. The car was originally a 1.7 then converted with a big bore kit.

Jorge...I was talking about a spacer on the GT mount...washers etc....I haven't seem any spacers for the header to muffler....you could fab

Really it's best to use the stock muffler mount and a muffler with the curve banana shape.

Had a customer once that allowed us to put a dimple in the muffler to clear...it was ugly but on the backside so not seen....crappy fix but he did not want to buy a new or different muffler

It's best to use stock parts if at all possible especially for a street car

Did they convert to 2.0 exchangers as well? They look like they may be 1.7’s

@mepstein It has 2.0 heat exchangers. This is an old photo before i got rid of the modified exhaust hanger with tabs, attached below.

@johnhora Ahh, OK that makes sense for the GT bracket. The car will eventually get a custom headers from MSDS but for now, maybe a dent in the muffler will suffice. I agree, not a great fix, but as you say it's be on the back side. It already has a noticeable divot from when I first i stalled it then noticed it was touching. I guess the question is what tool to use, and can I harm any internals to the muffler?

Click to view attachment

Before you dent your muffler, you may want to contact Ben and ask for his opinion. Ben has always been helpful with his products. 914/911 style mufflers have various baffles welded inside. You wouldn't want to break a weld or damage a baffle and alter the internal exhaust flow. It might not matter, but then again, it might.

@MB911

@maf914 Thanks for the diagram! I had messaged him directly earlier. Maybe he'll respond here so it can help others in the future.

Remember a tailshift equipped car never came with 2.0L (/4) HE's

Wow. Good point. Time to go side shift. - It’s worth it.

Were the 2.0 exchangers really this much shorter?
What I'm getting at is the change to side shifter may not get the clearance needed.

Haha, I just need to get her back on the road right now. I've finally made my way through the mountain of 914 parts boxes and can see the light at the end. I can't bring myself to buy another large piece right now. I think I'd lose my mind.

Not sure. In a message to Ben earlier this year he says, he runs this exact muffler on his 911 with no issue. He seem to be fine with the transmission denting the muffler slightly. I reached out here to see if others who bought his muffler had similar issues.

Mark, do I remember correctly that you guys are building similar mufflers now? Or was that a fever dream from to much 914world scrolling?

I think I'd lose my mind. - A requirement of 914 ownership.

Last run ......looks more likely to fit 1,71,8 headers,,, 911 mount behind the engine,,914-6 mufflers had longer header to muffler stubs... In Bens defense,,the muffler bus, got way to complicated..

I used another flange with a gasket on each side as a spacer to move the muffler back. There is plenty of room with these mufflers to move them further back.
http://www.914world.com/bbs2/index.php?aut...ch&id=13080

Thanks for the info. Did you fabricate a new flange, or cut them off old headers? If fabricated what material, CNC?

Yes we are.
I’ll check to see if we have some 3/8” flanges. Let me know if you need a set $25+ actual shipping. Can send priority. 1st class only goes to 1lb.)

Mark

Ben sold the flanges to me, when he was still making headers and mufflers.

Jorge,

In the area you are having issues with you can indent the muffler if need be. It is clear the issue is the mismatch of tail shift, and 2.0 heat exchangers. That combo never existed. The 1.7 and the 1.8 heat exchangers moved the muffler in a different position.


Just an FYI my first new run of mufflers will be ready around October.

@mb911 . Thank you for the reply Ben. Any pointers on how to indent it? My current thoughts were to place the muffler on plywood covered with towels, to absorb blows and help reduce scratching on the exposed side, then hit with hammer and a drift. Thoughts?

I would really look at a way to space it backward using the flanges, that is if there is room obviously, vs. creating permanent deformation to this nice muffler.

You might eventually want to convert your car to side shift where the spacers wouldn't be needed and you would still have a nice muffler, or who knows sell this part later on.

Denting it seems like a last resort solution in my book.

Other option is maybe sending it to Ben so he can properly cut and create a clearance recess.

Again, the flange ideas seems like the cleanest and pretty simple option if there is room.

Good luck!

@Mikey914 Mark I'll buy a pair of flanges from you if they are available. I think i have an extra pair of gaskets for the flange sandwich.

Thanks for all the help everyone!

I have steel ones if you need flanges.

That'd be great. How how thick are yours and how much ?

They are 3/8" and I know usps priority mail will be 9 dollars. So I could send a set for $20 total.

@mb911 OK good to know.

I'll wait to hear if @Mikey914 has any left, since I've already told him I'd buy some from him. But I'm glad to know you have some available if he does not.

Thank you again!

I can let you know Tomorrow afternoon as soon as I'm back in. I'll post up.
Mark

Please do not just dent that beautiful muffler; additional flanges is the best route.

Added bonus - if you add flanges you can probably use a standard muffler hanger and not worry about the GT hanger. The standard boomerang hanger is better all around. Several of us have had issues with the Tbolts breaking and the muffler left hanging by the heads. The standard hanger is pretty bulletproof for supporting the muffler.

Zach

I don't have any stainless available right now, but need to cut a few more up for another run, so I'll go a little heavier on the 2.0 flanges. I should have these ready in 7-10 days.

Mark

@Mikey914 sounds good. Thank you!

@VaccaRabite Good to know. Tha k fully i still have the correct old 2.0 hanger. Might just do that.

@Cairo94507 Thankfully I came to my senses, I will be doing the flange sandwich. Also, I need to see your car! I'm biased towards Irish Green. I'm in Culver City.

@Mikey914 just checking in. Any updates on the flanges?

Just need to get some cut up. Should be about 10 days. Will be doing some 2.0 and 1.7