[markpj23]

Wondering if I can put catalytic converters on a 389 dual exhaust setup in a '64 LeMans. Yeah I know I don't have to but I don't have to go to disk brakes either.

Are there high-flow units out there that won't steal too much power / add too much back pressure?

Thanks in advance,
Mark

[cm_ls1]

i just got some 3" magnaflow's , the rest of my system is 2 1/2"

make sure you get the stainless steel center as the ceramic core ones tend to die quicker.

i would suggest getting one size larger than the rest of your exhaust to avoid any flow restrictions.

[JC455]

Technically, it's illegal. The only cars that are supposed to have cats are the one's that came with 'em.
Another consideration is that cat. equipped cars have a relief in the sheetmetal that allows for an air gap (cooling) and gives enough room for the exhaust to NOT hang down and be ripped off the car (although Ford has a good idea w/ their straight off the pipe cats- quick light off and little ground clearance issues).

[markpj23]

Thanks for the replies / photo.

Illegal? In the State of CA only I assume.... can't believe that running a cleaner vehicle would be against the law.

Ground clearance and heat shield were on my mind already. Had a friend years ago who wedged a 302 into a Volvo station wagon... got the plug wires out of order and when he fired it up (probably 4 cylinders firing) all the raw gas caused that cat converter to really put out some heat

Mark

[Ccass]

here are good hi-flow cats that is reasonably priced. The more expensive 'metallic substrate' cats will hold up much better on hi-po cars.

http://www.pypesexhaust.com/mufflers.html

scroll down to the bottom.

[engineer]

it is illegal in all states, ( a federal EPA) law since cats have to be designed with certain temperature and fuel \ air requirements. not easy to do on a non cat car and actually improve the emissions. more likely to screw up engine performance and therefore emissions. Also illegal to add a cat to make a dual system or relocate one in a non factory position.