I just got a new muffler and tailpipe installed on my 85 Caprice with a 305
engine 4-barrel carb. The pipe looks smaller than the one that was on before.
At first I thought everything was fine, but now I think the performance might
be a little slower.
Am I imagining things? The end of the tailpipe is 2 inches in outer diameter,
and the pipe is kinked down a bit when it goes over the axle. The intermediate
pipe going into the muffler looks like it's about 3 inches diameter.
Is the 2 inch pipe standard? If it is smaller than standard, will it affect
I'm not sure of the OEM tail pipe size but if it is 1/8" to 1/4" smaller I
really doubt that you would feel any performance loss unless you were
referring to wide open throttle where you need all the exhaust flow that you
can get. Actually a slightly smaller exhaust can add to the low and mid
range torque, make most driving feel stronger.
If you feel a loss in power it's more than likely the muffler. Most
aftermarket mufflers are basically universal on the inside as far as the
muffler baffles are concerned.
There is really no standard in after market replacement exhaust parts.
Exhaust shops have to cobb the parts more often then they will admit. Even
parts from the same manufacture that are supposed to go together with
When you go in for Exhaust work, you have to specify pipe size. If not
the catalog may list all cars as using a 1-7/8 pipe when only V6 cars did.
Not to mention if you don't check it out, before it is installed you get
weird stuff like a 3 inch mid pipe going to a muffler with a 1-7/8's outlet.
Really the only way not to get screwed in After-market exhaust, is to
use High end parts. Name brand mufflers, and catalectic converters. Even
then, you want custom mandrel bent thick wall tubing. Most after-market
exhaust systems have thinner wall tubing then what was OEM.
The kinks in the pipes on your car are from a tubing bender. They only
way to bend tubing with such a thin wall with out kinking, or reducing
diameter is what a mandrel type machine. The mandrel type has something
inside the tubing to keep it from compacting.
As for 2 inch pipe on a single exhaust on a stock 305, it won't kill it.
Yet it is creating back pressure. 2-1/2 is about as small as I would go. But
then again I like my motors to breath.
That's the truth! My friend brought his Jeep Wagoneer w/ 360 into a local
muffler joint.. He had a reman. engine with no miles on it and after this
trip to the muffler shop, it had no power.. He didn't think anything of it
but a year down the road, he was crawling underneath and noticed that the
place had put a section of 1.5" pipe in there to fill a gap where they
obviously had no other pipe !!! I think he wanted to drive his Jeep
through the place after that..
Thanks. This was the ONE time I didn't scope every detail out in advance,
since I was so tired of trying to find a place to replace my warranteed Walker
muffler, couldn't find a place, then got the cheap price of $80 for a Maremont
muffler and tailpipe (labor included) and bit without asking any questions,
ASSUMING that the stuff would be the same dimensions.
Man, let your guard down once and see what happens..............
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