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Discussion Starter · #1 ·
looking to replace the exhaust system on my 55 Vert with a 327. I was wondering if there is anything to gain by going from 2" Rams Horns to 2.5" Rams Horns? Would there be any clearance issues? Will 2.5" tubing fit though the holes in the frame cross member? I'm also looking at using Magnaflow mufflers and i want to keep it fairly quiet. i would appreciate any advice.
 

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IMHO, 2.5" is too big for a 327.

Charlie
 

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my 55 convertible has a 454 bb in it and i am running short headders due to the x member and twin 2-5 inch pipes which fit through the chassis
 

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Tight.

2.5" is tight, but has been done successfully. We did.

Be advised, because of the X-member, the muffler length must not exceed 28.5" overall.

The MagnaFlow Performance pn 12224 (2" center inlet, 2" offset outlet, oval body, 20" overall length) will have a mild sound behind a stock motor.

We are running the 2.5" pn 12256 (24" overall length). Link to pic.
http://www.trifive.com/forums/picture.php?albumid=4228&pictureid=36872

One kink when running aftermarket 2.5" rams horn manifolds - our manifolds are so fat, it required moving the engine toward the passenger side (when converting to side motor mounts) approx ½", for steering box clearance.
 

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Discussion Starter · #11 ·
I am looking for a very little sound to quiet in the interior. So are the 2.5" pipes any ware close to rubbing in the X frame?
 

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Yep.

Oh yeah.
 

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Just so you're not disappointed, I think you're on the road to be disappointed. :)

Asking for very little to quiet, in the interior of a convertible, is a very tall task with anything but a close to stock muffler. If you don't want to hear a rumble, which it sures sound like you don't, listen before you buy, it's going to be hard to find.

Regardless of it it fits, I'll again recommend against 2.5" for a smaller motor.

Good luck on whatever you do.

Charlie
 

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You're not running enough cubes to need to move that much air. I'm running 440 cubes and a 2.5" exhaust system. I noticed some low end torque loss on my 350ci Blazer when I switched to 2.5" from 2".

If you're building a racer and you're looking to go as fast as possible, moving air through the engine is important. Given you're concerned about having a largely quiet exhaust, I don't see you going to the track. :)

So I've given my opinion on why you shouldn't have a 2.5" exhaust, what's you're reason for wanting one?

Charlie
 

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Discussion Starter · #16 ·
I picked up a new set of 2.5" corvette manifolds a while back but but I also have a set of the 2". I have always been concerned with clearance issues if using the 2.5". I may also need to find out if someone like Walker makes a stock muffler for the convertible.
 

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I am looking for a very little sound to quiet in the interior. So are the 2.5" pipes any ware close to rubbing in the X frame?
If you are wanting quiet, whatever size of pipe, don't use metal straps welded between frame and/or floor pan and exhaust system to hang it - use the rubber/cloth-belting type of hangers. Metal hangers transmit lots of vibration (sound) turning the body into a sound box a la a guitar.
 

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I picked up a new set of 2.5" corvette manifolds a while back but but I also have a set of the 2". I have always been concerned with clearance issues if using the 2.5". I may also need to find out if someone like Walker makes a stock muffler for the convertible.
Re: 2.5" exhaust manifolds, like the carb/intake combination needs to fit the particular engine package for best performance, so the exhaust also needs to fit the engine package for best performance. Generally, the 2.5" manifolds don't make as effective combination for that size engine, esp. in your state of build, as the 2" manifolds. Maybe what you are looking for are headers designed for your specific engine size and build.
 

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Discussion Starter · #20 ·
i can use the 2"manifolds no problem. A friend gave me some POR high heat manifold paint. Have any of you ever used it?
 
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