280C exhaust swapout
 

I am in the process of converting my '74 280C CA model to a 49 state federal model. The thermal reactors are removed and I have put in place (temporarily) the US exhaust manifolds. Do the manifolds look correct?

I don't have a federal version to look at and for those of you that have one I am hoping to hear, yup, that's what mine look like.

Thanks,

Doug

Yep, those are the same style manifolds that are on my 72 280CE. Use a W108 280SE mufflers and you'll be able to run dual pipes all the way back.

Really, I can install a W108 280 SE exhaust system and it will bolt right up?

I have brand new MBZ downpipes for these manifolds, hopefully those would work. with the W108 exhaust system.

I'm hoping to yank the Thermal Reactor in my '73. How hard was it? any tips?

The muffler will probably work, probably not the entire system. You'll either need to have a muffler shop bend you up some pipes or see if you can score a system form a Euro W114 280CE.

It was pretty easy to remove. First remove the battery and battery tray, then the AC compressor, then the steel hot water heater pipe running along the head, then the air injection rail, then you can get at the 12 manifold nuts. Some are tricky to get at, try a 12mm 1/4" socket w/wobble, then lastly the 4 manifold to down pipe bolts, which are easiest to get from below with an extension. I spent about 2 hours getting it all removed.

Mufflers work fine from a W108 280SE/L. I have this setup on my 71 coupe.

Pipes can be modified, but W108 pipes are not plug and play. Routing is different especially as you approach the rear axle and beyond.

Very nice when finished, as you have that great dual exhaust note. The coupe exhaust has been obsolete for many years, the single outlet sedan exhaust is what is substituted.

Jim

Allright, it's all done now. The CA thermal reactors are gone and the 49 state exhaust system is now in place. I had a local muffler shop weld the new downpipes to the existing system.

The result? WOW!!! No difference, actually. Somewhat of a disappointment. well, it's quieter.

But, with the NOS Holley economaster with automatic choke and the new quiet exhaust this car is truly a pleasure to drive. Drives like fuel injected. What a great car.

Although the M110 is a noisy motor. Maybe I need to adjust the valves.

All in all worth it to clean up the engine compartment.

I got a chuckle out of this. Restrictive exhaust systems will only be a problem if the engine can push out more HP. I believe that this applies to M117 5.6 V8 motors and 6.9, but probably not so much for a carburetor 2.8 liter engine.

Still, you may see improved fuel mileage.

If anyone wants my old thermal reactor system with the air injection manifold, it's free to whoever wants to pick it up in walnut Creek, CA.