When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The 5 pin module retards the ignition timing 10 degrees when the pin with the black arrow in the photo below is grounded.
To hook it all up you just plug the 4 wires in the HEI to the 4 other pins on the module like they are on the stock 4 pin module. You then run a wire from the pin with the arrow to one side of the pressure switch. The other side of the switch, run a wire to ground. Hook the switch to a manifold vacuum/pressure source. That's all there is to it.
Of course you still have some adjustments to make. Start the pressure switch out at 1 to 2 psi.
I would limit the the distributor to 20 degrees advance. You can find how to limit the advance with a search here or google. I would put a limiter on the vacuum advance so you can adjust that also. This can be found in a search too.
I would set the timing to 36 degrees total all in at 2800 to 3000 rpm, which would give you 16 degrees at idle. Hook the vacuum advance to ported vacuum source. As terrys6t8roadster has stated, there will be little no no vacuum in the manifold to use, so ported is the only way to go.
You'll have to just play with what manifold pressure (boost) to retard at and the maximum timing it will run best. You'll also have to experiment with the vacuum advance limiter to get the best off idle response and cruise smoothness and gas mileage.
The 5 pin module retards the ignition timing 10 degrees when the pin with the black arrow in the photo below is grounded.
To hook it all up you just plug the 4 wires in the HEI to the 4 other pins on the module like they are on the stock 4 pin module. You then run a wire from the pin with the arrow to one side of the pressure switch. The other side of the switch, run a wire to ground. Hook the switch to a manifold vacuum/pressure source. That's all there is to it.
Of course you still have some adjustments to make. Start the pressure switch out at 1 to 2 psi.
I would limit the the distributor to 20 degrees advance. You can find how to limit the advance with a search here or google. I would put a limiter on the vacuum advance so you can adjust that also. This can be found in a search too.
I would set the timing to 36 degrees total all in at 2800 to 3000 rpm, which would give you 16 degrees at idle. Hook the vacuum advance to ported vacuum source. As terrys6t8roadster has stated, there will be little no no vacuum in the manifold to use, so ported is the only way to go.
You'll have to just play with what manifold pressure (boost) to retard at and the maximum timing it will run best. You'll also have to experiment with the vacuum advance limiter to get the best off idle response and cruise smoothness and gas mileage.
Mike
This sounds like a great idea, but the links take me to something different than what you described. The links do not seem to be going to the correct item.
04-26-2018, 06:08 PM
How to setup a cheap boost retard with your stock HEI distributor!
