Hi guys
I'm getting dual system put on the 56 tomorrow. Just wanting some suggestions on size. Some people tell me 2 1/4" others say 2 1/2". What do you think?

 

2 1/4" will be fine. 2" would be just as good on that car unless it is highly modified. Since the 56 was available with factory duals, you may not have to cut the X member in the frame like you have to on a 54 and 55.

 

i have dual 2 1/4 stainless on my '55 S88 with Flowmaster 40 series stainless mufflers. No fitment issues. Seems to run smoother at high speeds than before and gets a mile or two extra MPG...of course, that is just seat in the pants observation more than any scientific evidence. I've been told to fit an H pipe behind the transmission to help low end Torque but I don't have that on my set up and the larger pipes didn't seem to affect it...again, seat measurements.

Stainless should hold up better in salt, snow and sand but make sure they use stainless wire at the welds or they will rust quick at the weld seams. Expect to pay a pretty penny more to go stainless but it should last a very long time so i think the added cost would be worth it.

 

Thanks for the info. I've just picked the car up now with 2 1/4" dual system fitted. Sounds great. At least people won't think I'm driving a hybrid now

 

I am curious if your 56 has power steering and if the frame X member was already cut on the left side. What kind of mufflers did you use? Glad you are satisfied and welcome to the site. We would love to see some pictures of your car.

 

My 56 doesn't have power steering or power brakes. The holes were already in the chassis so that made it easier. The mufflers are a straight through set up. There aren't too many of these cars over here so the guys doing the exhaust were basically starting from scratch. I'll get some photos up soon