75 datsun exhaust

[2wheel-lee]

FYI, my 1975 620 has the original exhaust and muffler. The exhaust tubing is 1-3/4".

[NVFireFighter]

On 11/23/2018 at 5:25 PM, datzenmike said:

 

 

 

 

 

The '75 through '79 use a 4 into one exhaust manifold with a single down pipe.

 

 

 

 

 

Is there a better manifold for a 78'? Mine has that shield over it and it's a buzzer/vibration sound that drives me bonkers! Plus I would like to re-do the whole system and a little performance wouldn't hurt..... 

[datzenmike]

Just tie the warm air shield down with stove pipe wire. It's part of the ATC...auto temp control, along with the pipe from it to the air filter snorkel. It's free and will run much better with it in colder weather.

 

Nothing easy and cheap. It's not very restrictive so there's little to gain.  Only when you get into a larger carb or multiple carbs with a 'larger' cam does the stock exhaust start to hold you back. I think the 620 uses a 2" down pipe to the muffler. Go up to 2 1/4" and replace the muffler with a turbo style. (but not a straight through kind) The turbo ones have packing and sound absorbing material inside and will be noisier than the stock one. Don't expect the world form this. I put a header on my stock L16 and there was no improvement. The original exhaust manifold was that good.

 

 

[NVFireFighter]

2 hours ago, datzenmike said:

Just tie the warm air shield down with stove pipe wire. It's part of the ATC...auto temp control, along with the pipe from it to the air filter snorkel. It's free and will run much better with it in colder weather.

 

Nothing easy and cheap. It's not very restrictive so there's little to gain.  Only when you get into a larger carb or multiple carbs with a 'larger' cam does the stock exhaust start to hold you back. I think the 620 uses a 2" down pipe to the muffler. Go up to 2 1/4" and replace the muffler with a turbo style. (but not a straight through kind) The turbo ones have packing and sound absorbing material inside and will be noisier than the stock one. Don't expect the world form this. I put a header on my stock L16 and there was no improvement. The original exhaust manifold was that good.

 

 

 

Thanks Mike!