Muffler Sizes 1931 Car

Could someone tell me what the difference in muffler size would mean in performance or loudness . I have a 1931 Reo Royale 358 cubic inch motor . A friend measured his Royale original muffler which is 30 inches long and 6 inches in diameter . The only size I could get was 24 1/2 inches long and 6 inches in diameter . Would this present a problem ? I should also mention that the inlet is 2 1/2 inches and outlet is 2 inch on the muffler . I live in Canada so getting parts across the border is not easy .

Mark, I'm having mine custom made. Getting the sizes correct is important for visual originality but I think that performance is mostly dictated by those inlet and outlet diameters. I would go 2-2.25 on the outlet only because I abhor tiny pipes on a big engine.

In terms of quiet performance I'd also be concerned with the internal construction. Some of those long, round mufflers, for example used on Packard Eights 33-36, contained an internal resonator chamber.

As long as the inlet and outlet are the same size as original you should be ok. It may be slightly noisier than original. Later model cars often had a muffler and a resonator as 2 separate pieces. You might add a resonator for more silence.

I don't know what is hard about getting car parts across the border. There is no duty so your only extra cost is shipping and customs duties. If you have it sent by mail there is no customs brokerage fee but there is a fee if it is sent by courier.