56 exhaust system

[Steve H.]

Hi all, I need to know if the mufflers on a 225 horse power '56 are supposed to be round or oval. I thought I read somewhere they were all round in '56 but the JG soes not say one way or the other. Some vendors offer oval or round off road mufflers, but I was told the off road were only an option that year. Also, were the pipes welded and if so where?
Thanks in advance for your help.

Steve #28428

[Dennis C.]

Re: 56 exhaust system

Steve, Head pipes from manifold to X-member are a one piece item. The next pipe and the muffler are a welded together affair with no clamp at the muff. So much for facts - now, I'm not sure if the original muffs were oval or round "off road" or not, or if they were an option (which I doubt in '56), BUT I would install the round off roads no matter what, unless you are deaf or never start the engine. Sound wise, the oval muffs belong on a hearse. JMHO

[James F.]

Re: 56 exhaust system-Steve

Steve,
Oval mufflers only in '56. "Off road" muffler terminology was not invented until later in the life cycle of the solid axle. Regards,

[Dave Suesz]

I get a lotta flak for this, but "all" 55-57

were supposed to be 4" round mufflers. The 55 was supposed to have muffler and pipe assembly LH 3718851 and RH 3718852, which used muffler 3717324 (or optional Arvin 3720948), but apparently the mufflers were more GM's choice than the customer. Both were 26 1/4" x 4". NO change 56. In 57, the parts changed to LH 3736957 and RH 3737644, but still used the same 3717324 muffler. The optional Arvin 3720948 muffler was used until December 56, and was replaced the zinc-plated 3744928 in January 57. The plated assemblies were then called LH 3736957 and RH 3737644. There is anecdotal evidence that some 55's were equipped with oval mufflers, probably leftover 54's. I know VE55S00517 was originally equipped with 4" round mufflers.

I went on a personal quest to aquire this information, because my Dad provided an accurate description of the originals, but EVERYBODY, dealers, etc., including the NCRS, said I should have oval mufflers. My thanks to Ken Kayser, who provided me the data to vindicate my Dad.