vetteguy75

What does recurve the HEI distributor mean? AND how do you do it? AND how does it help performance? AND does it have to be done with a new HEI distributor?

Scott Marzahl

It simply means that you change the timing advance curve from stock.
The stock setting is not performance orientated but more for emissions.
Inside the distributor are two small springs which control the tension to the two small half moon shaped weights. By changing springs with ones of lighter tension, the weights can move outward sooner and faster which changes how fast your timing comes in. One also changes their timing to say 36 degrees at 3000 RPMs without the vacuum advance connected. This starts your ignition firing process much sooner, which in turn creates more power.

tlynam

Well said, but, you can't just throw the lightest springs in the kit in there. Look out for detonation. Too much advance under load at lower RPMs will cause pinging that can do alot of damage.

Scott Marzahl

I might add that your distributor is best dialed in for your application on a Sun Distributor machine. You can do it on the car too, it just takes more time and trial and error.

vetteguy75

THANKS! It makes sense now.

Tim H

Any older car I buy, first thing is unhook the vacuum advance and adjust the timing mark up to 12 and lock it down, then hook up the vacuum if you want.
Get a dial back timing light and then play around with idle timing and advance and total timing.