I an at the point where I am considering some up grades on my 1980. I'm thinking of going with RB header and pre silencer then stock from there back. Also, RB Weber or Holley carb set up. The engine is 100% stock now, not an FB, was wondering an estimated HP for the two upgrades? What would the two up grades plus a street port estimated HP get me? Thanks in advance.

 

The RB header and presilencer wakes up any 12a or 13b. Here are some numbers;

 

Do not use the Holley, you will be disappointed more than likely. Go weber or mod the nikki. Also you want to get the RB Street Port exhaust for maximum effect of any carb you put on there.

 

My stock port 12A went from about 118whp (I know that is kind of precise for "about", but that is what the dyno showed) to about 135 whp when installing the rb header and presilencer followed by 2-1/4" pipe going to a stainless steel turbo muffler. That was all with a stock stripped Nikki with larger fuel jets. With a mild street port and the same exhaust and carb, the HP was about the same, 135whp. Boring out the primary venturis of the Nikki brought the HP up to 145-150 whp. I did also increase the size of the exhaust system downstream of the header (after a buddy went off track and crapped everything downstream of the header), but that had no noticeable effect on the horsepower.

Another buddy used a holley on his race car (stock port 12A) and the driveability sucked going through corners. It would stutter/die and then come on at usually an inconvenient time.

Don't know if that helps, but.....

Carl

 

I’m stock as well and will be going the modded Nikki Carb setup route eventually. Although it doesn’t seem that Yaw power and Sterling are doing modded Nikki’s anymore - there seems to be some people within the state that offer rebuilds and modding the Nikki a bit. I need a rebuild on mine and figure I can have one these people mod it to get a little bit more Oomph out of the Nikki along with a full RB exhaust.

 

I dynoed my setup with the RB Dellorto carb and it was putting down 134whp. I then hogged out my nikki and it revs faster and better and feels like its putting down a bit more power as well. Only a butt dyno, but I'm pretty sure it's putting down more HP to the wheels.