I am transplanting a 1999 5.2l from a 1999 Ram SLT truck into a 1940 Chrysler 2 door coupe. Keeping the EFI and PCM and wiring.
I want to use dual exhaust with no cat convertors.
What do I do with the before and after oxygen sensors? They were before and after the cat convertor on the truck.

Mike

"In general" you will need the front oxygen sensors for the engine to run. The back oxygen sensors check to make sure the catalytic converters are working (which aren't there now), so that would create a MIL (or check engine light) code. A '40 coupe probably won't have a light to tell you there's a problem, but the computer might put the engine into "limp home mode" (not sure about that) which would kill your mileage & performance.

I'm not sure about the emission laws in Canada, but the old-school way of doing this was to add "MIL-eliminators" which would modify the signal from the rear oxygen sensors so you don't get a "check engine light code"

Purplebeeper, thanks for your reply. In Canada, anything older than 1990 does not require emissions testing.

I will look into MIL eliminator. Hopefully others will chime in how they did that.

Mike

If the engine is mostly stock, I'd run dual cats, one in each headpipe. Installing a"downstream" sensor after one of the cats.

These will muffle the exhaust a bit and likely keep the check engine light off.