pcmhacking.net

Hi All,
Has anyone changed from a dual plane manifold to the single plane on the 355 engine?
Just did a couple of dyno runs and it doesn't want to make any power after 5800rpm. Fuel looks good and my timing is around 34deg. running the 1000cfm 4 barrel throttle body.
(I know Harrop says they are good till 5500rpm so I'm guessing that may be the problem

How does it compare to the dual manifold power curve? I would expect the single to maybe Rev a bit more but loos e a bit of low rpm torque.

Not sure. I do have a single plane. Think I might have to put it on and do another run. On the street this engine has no problem revving out to 6600rpm & feels like it pulls all the way. Different story with the load on the dyno tho.

The Harrop single plane is really good. Will pull hard in the top end. I had one on my turbo 5 litre. Didn’t notice much of a loss down low but I noticed the top end