Anyone have suggestions about what size exhaust pipe to run out of the Clifford shorty headers? Looks like the end of the output tube is 2” outside diameter but could accommodate up to 2-1/2. This is going on a street car so I don’t want too too much noise. Thanks!

I would run no bigger than 2 1/4". Depending on engine mods, you will likely be fine with 2" or 2 1/8". Depending on the year/model, the factory pipes were likely 1 7/8" or smaller.

-Matt

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-MattMan
LEANED & MEAN

It depends very much on the engine mods you have. Please tell us about your engine as it is now and/or desired modifications. What do you consider loud? Please describe. Also, are you talking about full dual exhaust, or Y'ed into a single?

Personally, if you are bothering to have headers on your Slant, I would not bother with anything smaller than 2.5" single exhaust, or 2" duals.

Lou

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Home of Slant6-powered fun machines since 1988

Thanks; good questions. The long and shorty of it is that I’m planning on running the engine as otherwise stock; maybe moving to a Aussiespeed long intake with a four-barrel carb or even EFI as the budget permits.

As for sound, I’m thinking toward the quiet end of the spectrum but not creepy quiet like a Tesla or Prius. A little rumble would be OK/expected but I still want to hear the stereo eh.

I’m thinking dual exhaust all the way back as long as the available space permits it.

Hope that helps; any insight is appreciated.

Update on this project (or, What I Did on My Summer Vacation): Clifford shorties are installed; while I had that side of the engine available, I cleaned it up and gave it a new coat of blue paint. I got a 2-1/8 diameter kit from Speedway, got all the pipes cut, welded up and hung up. At the stock location near the trans mount, I fabbed up a longer bracket to hold both sides of the pipe then built a mirror image of the stock hanger to fit in the driver side. Painted the intake, used a Remflex gasket, created a bracket for the choke. And new motor mounts plus a “mini-starter”. Finally, put in tail pipes to put the exhaust out both sides behind the tires.


Here’s a link to a video showing the mostly completed project: https://youtu.be/yiXetp5H-Rg

Questions remaining: seems like I’ve got a giant hissing sound—any thoughts on why? I torqued all the manifold bolts to the reccomended 5 ft-lbs. Maybe I need to go up on the torque?

Also, car idles nicely but has died s few times just sitting in park—and, frustratingly, died instantly every time I put it in gear tonight although it was warmed up and the choke was off. I suspect fuel pump or something’s wrong with the kickdown linkage. Would appreciate any ideas. Thanks!

Here’s a picture

Nice purdy engine.

Probably you have a vacuum leak at intake to head. 5 lb/ft probably not enough to seal. I just install the same get-up and torqued to 8 lb/ft. with the intention of, if needed, going to 10lb/ft. I replaced all studs, and used brass nuts with a dab of copper anti-seize on them.

Torque spec assumes clean drag free turning of nuts. I you used old studs and nuts, the actual clamping force exerted could very from stud to stud. In other words a 5 lb/ft reading on a freely spinning nut would have more clamping force than a stiffly turning nut with the reading.

Try 8lb/ft and observe compression of gasket. Tip #2 on Remflex package states; "gasket crush should be 50%."

What year is your car. I see a Saginaw power steering pump, and a very different bracket holding it in engine photo. Reason I ask is, I'm suffering with a TWR pump and goofy wracked bracket that required several hours of farting around shimming and fitting it so its pulley aligned with damper. If this red neck garage get-up don't hunt, than I just as soon convert to the much less expensive and simpler Saginaw arrangement.

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82' LeBaron Convertible; the new Chrysler Corp
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Many thanks. I will twist the manifold nuts up to 8 ft-lbs and see what happens.

This is on a 1980 Plymouth Volare station wagon. I think the pump bracket is similar to the brackets on other Volares. I think it's probably the stock setup as everything else on the car has been original so far.

BTW, it seems that neither Lokar or Bouchillon makes a kickdown cable for a 1 bbl in front of a 904. Is there any other cable-based solution or should I put this on my list of reasons I have to upgrade to a 4-barrel?

Torqued the manifold nuts down to 8 ft-lbs. Still dies out when shifting to gear in normal circumstance, although if I rev it up it immediately after shifting, it now sometimes will keep running (albeit poorly). I disconnected the kickdown and confirmed that was not a factor. I’ll try moving up to 10 ft-lbs to see what happens. Gasket seems to be about 50% crushed now; seems it could take a little more.

You likely have the intake or headers hanging up on something and preventing the flat sealing of the intake to the head. Also, the remflex may not cover the exh flange on the headers completely and allow an exh leak, but that would be a popping/farting sound, not hissing. You need to always put the int and exh on with no gasket and check for flat/parallel alignment before assembly. Remflex cannot fix misalignment. We just found a big hole on Brian Mimken's where the remflex meets the Clifford shorties and does not cover all of the flange opening.

Lou

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Home of Slant6-powered fun machines since 1988

If you need any help I am on the far southern edge of Cook County.

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Official Cookie and Mater Tormentor.

You might consider moving the tranny cooling lines, they are very close to the headers it appears from the picture. Perhaps I'm not seeing it for what it is. If they are 1/2" or more away should be fine. I ran mine on the other side of the engine, along the frame, but I fabricated flexible lines.

brian

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Finally had the chance to take the intake manifold off to check for alignment, etc. I think I'm seeing that the top of the intake did not fully seal up--probably it was being pulled off line by the headers. Picture of the center section below. I disconnected the headers so the rest of the exhaust is not pulling on them. Seems that should help get a better seal across the top. Any other thoughts/tips/do's/don'ts? Hoping to get it together this week.

@67 Dart: Thanks for the idea re: tranny cooling lines. I think there's at least 1/2" there but I will take a look to confirm.

Sounds like an excellent idea. What's a good source for Slant Six manifold studs/nuts?