VCCA Home Forums TECHNICAL - 1945 AND NEWER 1955-1957 55 muffler

I plan to convert my 55 belair to dual exhaust. Recent checks with vendors indicate a muffler for 1955 non-convertible with single exhaust, but they don't show mufflers for dual exhaust. Would the single exhaust muffler be used on both sides of dual exhaust system for 1955? Is there any difference single vs. dual?
Sid

The 1955 V-8 single exhaust cars (except convertible) used a long 34 inch muffler. The convertible used a short 28" muffler due to the X type frame limiting space.
The dual exhaust cars (with powerPac 4 Bbl engine) used two shorter 28" mufflers including the convertible.
The convertible single exhaust muffler was NOT the same as the short dual mufflers as the dual mufflers has more restriction to eleminate excessive noise.

In late 1955 Chevrolet sold a dual exhaust converson kit for installing duals on a single exhause engine.
It consisted of the brake and fule lines for mounting them on the out side of the frame away from the exhaust heat.The right muffler, exhaust and tail pipe and hangers. This would be the short muffler. The cross over pipe was cut off of the existing left exhaust pipe and a plug provided for plugging the opening.
Kit also came with a pair of the single exhaust type tail pipe extensions (not the powerPac extensions).

In 1955 the powerPac cars had only the 4 Bbl. Carb. and dual exhaust to boost horse power.

IN 1956 things continued ALMOST the same except in mid-year all dual exhaust cars used a pair of the longer mufflers rather than the short (except convertibles). The dual exhaust kit was also sold for single exhaust cars.

The 1956 PowerPac engines had the 4 Bbl and dual exhausts PLUS a higher compression ratio and a high lift camshaft giving the engine a 25 HP boost over the 180 HP 1955 Power Pac engine.. (the higher lift cam also used in Power Glde 2 Bbl. cars giving them a 8 HP boost.)

All in all there were TEN different mufflers used on the various V-8 engine combinations in 1955 and 1956.

For the average the right dual muffler lasted about 18 to 24 months for most owners. The left several months longer. Chevrolet sold Aluminized mufflers for replacement ( at a higher cost) and they gave a little longer service

In 1957 A connecting pipe was added (on dual exhaust cars) that ran from the left to right exhause pipe to force more hot exhaust through the right muffler in cold weather to help prolong its life. It helped a little. By tnis time owners were more reluctant to have duals and in 1958 Chevrolet made dual exhause optional on a 283 2 barrel or 4 barrel engines to give a wider choice.

One more exception. Dual exhausts was not available on station wagons or Nomads in 1955 due to the right tail pipe would not clear the gas tank. However they could be equipped with the 4 barrel carburetor.

Thanks Gene. Both Napa and O'Reillys sell a 27 inch muffler that comes pretty close to what the 55 had originally. Appreciate your help as always.
Sid

Is your 1955 a convertible or hard top?

Hardtop.

That is what I remembered.

And best of all Gene, you remember so well !