440 Jensen Interceptor Exhaust Crossover / Balance Pipe

[Cal Tonsley]

Hi, we have a 1970 Jensen Interceptor in our shop that needs some repairs and mods. These cars run a 440RB motor and 727 Trans package. The vehicle is currently running an aftermarket style twin 2.5” exhaust system off stock manifolds with mufflers and resonators and no crossover pipe. The exhaust note is currently too rowdy for the client, he’s looking for a more refined, quieter note that better suits a “Grand Tourer” type vehicle.
We’re thinking that we’ll change the resonators plus add a balance pipe and would like to know if anyone can suggest an optimum location back from the manifold outlets for the balance pipe? Of course this will also be dictated by undercar space etc.
Any help would be much appreciated! Have added a couple of pics of some other Jensens FYI.

 

[H22A4]

I can’t help you with your question but will say those Interceptors are a neat bit of history! Some of them came with 440 six packs that Chrysler sold to them in 1971! Not that I want to spoil the fun but the six pack setup was not a success for Jensen.

 

[496 polara]

The closer to the engine generally the better. Space and access needed permitting.

 

[4spdragtop]

I would thank @VOETOM would have some great insight/advice.
Very cool car! Got more pics?

 

[Cal Tonsley]

I can’t help you with your question but will say those Interceptors are a neat bit of history! Some of them came with 440 six packs that Chrysler sold to them in 1971! Not that I want to spoil the fun but the six pack setup was not a success for Jensen.

While not a SP, the vehicle in question is actually an FF - Ferguson Formula All Wheel Drive!!

 

[Xgoldfish]

I agree with 496 polara that the crossover should be closer to the end of the exhaust manifolds, perhaps just after the transmission if space allows. Let see pics of the real FF. Very special car. Not sure exhaust should be tamed, but can understand one’s desire to be discreet.

 

[RustyRatRod]

I would thank @VOETOM would have some great insight/advice.
Very cool car! Got more pics?

Exactly. You beat me to it. Tom is the man!

 

[VOETOM]

See if you can find a Dr. Gas X-type Crossover around there. I know he sold some overseas. They will smooth the exhaust tone but not sure the owner will be able to tell inside as much. Maybe I missed it but what mufflers do they use?

 

[Cal Tonsley]

See if you can find a Dr. Gas X-type Crossover around there. I know he sold some overseas. They will smooth the exhaust tone but not sure the owner will be able to tell inside as much. Maybe I missed it but what mufflers do they use?

Thanks, I’ll try and report back re mufflers next week once I’m back at work and can take a look at the car.

 

[VOETOM]

Cal, I looked at your Jensen factory style exhaust and it looks like you have zero room to play under it. I'd be sure it has the OEM mufflers (2" in and out I think??) and the factory resonators at the end and not just empty cans. I am sure there are some round mufflers that might fit (like those used on the Turbo FWD mopars in the 80s and 90s) but I can't tell about length or diameter of the originals from the photos I found.

 

[Cal Tonsley]

Cal, I looked at your Jensen factory style exhaust and it looks like you have zero room to play under it. I'd be sure it has the OEM mufflers (2" in and out I think??) and the factory resonators at the end and not just empty cans. I am sure there are some round mufflers that might fit (like those used on the Turbo FWD mopars in the 80s and 90s) but I can't tell about length or diameter of the originals from the photos I found.

Thanks again, the current exhaust is non factory in stainless steel with resonators that need to be replaced to give a more factory appearance. I’ll aim to get some pics to upload during the week. Really appreciate your help!

 

[VOETOM]

Thanks again, the current exhaust is non factory in stainless steel with resonators that need to be replaced to give a more factory appearance. I’ll aim to get some pics to upload during the week. Really appreciate your help!

There is no sound control in some aftermarket mufflers like the original mufflers will give and without resonators, it could be a beast with that big engine. The muffler volume is needed to get the sound levels down and who knows what the non OEM mufflers are like inside. Resonators were an important part of its original sound I am sure.