Blueprint 306 w Holley Sniper- Ignition Question

[AZMike75]

I'm getting ready to install my blueprint 306 crate motor (holley sniper efi) next weekend and have a question regarding the ignition. It's a 75 and had the stock ignition setup previously. The new engine has an HEI distributor- what am I going to need to change or swap out on the ignition end?

 

[Attac]

Mike
Just did this on a 351. Went from carb and duraspark to sniper and Hei.
Unplug your distrib plug that goes to duraspark harness and also unplug harnesses to duraspark box. The one harness will now be free and can just be taken out. I didn't cut the other harness plugs off that origionally went to duraspark box, we just sealed them and tucked them out of the way. Remove your coil and the wire that goes to "tach" side of coil can be removed completely. That is the wire that sends a signal to box so that your distrib will fire. The + side wire from coil will go to the red wire on your hei. The tach wire from sniper will go to the green wire out of hei. The red and green are the ones on the little flat adapter that you have to usually get separately but yours may already have it. I don't remember if blueprint included it on mine.you can also remove the duraspark box from your fender.
Chuck

 

[AZMike75]

Mike
Just did this on a 351. Went from carb and duraspark to sniper and Hei.
Unplug your distrib plug that goes to duraspark harness and also unplug harnesses to duraspark box. The one harness will now be free and can just be taken out. I didn't cut the other harness plugs off that origionally went to duraspark box, we just sealed them and tucked them out of the way. Remove your coil and the wire that goes to "tach" side of coil can be removed completely. That is the wire that sends a signal to box so that your distrib will fire. The + side wire from coil will go to the red wire on your hei. The tach wire from sniper will go to the green wire out of hei. The red and green are the ones on the little flat adapter that you have to usually get separately but yours may already have it. I don't remember if blueprint included it on mine.you can also remove the duraspark box from your fender.
Chuck

Fantastic info- thank you Chuck! Did you run the HEI through a relay? I read on here in a few spots that it's recommended.

 

[Attac]

We did not on the 351.
I will have to go look at mine with the blueprint motor. I used a full painless harness and I have a bunch of relays but I can't remember if One goes to hei on that one. I tested the wire we use for power to coil on hei when starting on the 351 and did not get a big noticeable drop when starting. I Guess if you did a relay would assure a 12v to it. Maybe viper wolf will see this and give us a lesson on this. He is way smarter than me
Chuck

 

[Attac]

Let us know how that motor does. I am looking at getting one for the one we are building now (oldest sons). The specs look really good with torque where we need it. 365/365 is better than my 331 from them.
Chuck

 

[Amac70]

why not run specific holley sniper ignition, so the computer can control it?

 

[Broncobowsher]

Follow the instructions for a GM, since that is what the ignition will be.

 

[BluePrint]

Hey Guys,

not sure which version of our 306 you have (with the big cap, or small cap hei) but both would just require a 12V to both the distributor, and to the holley sniper unit. make sure its constant 12V in all Key configurations (on crank and run)
Both HEI's we use do not control timing, and are a ready to run configuration

if you have the small distributor, like on our bronco edition, then you will want to piggyback the 12V distributor source, to the coil also.

hope this helps, give us a call anytime!

BluePrint Engines

 

[AZMike75]

Let us know how that motor does. I am looking at getting one for the one we are building now (oldest sons). The specs look really good with torque where we need it. 365/365 is better than my 331 from them.
Chuck

Will do and thanks for your input here- I really appreciate it!

Hey Guys,

not sure which version of our 306 you have (with the big cap, or small cap hei) but both would just require a 12V to both the distributor, and to the holley sniper unit. make sure its constant 12V in all Key configurations (on crank and run)
Both HEI's we use do not control timing, and are a ready to run configuration

if you have the small distributor, like on our bronco edition, then you will want to piggyback the 12V distributor source, to the coil also.

hope this helps, give us a call anytime!

BluePrint Engines

Thank you! I have the larger blue HEI distributor cap. I have a feeling I'll be calling you guys to make sure I've got this thing wired up right! Much appreciated!

 

[BluePrint]

Will do and thanks for your input here- I really appreciate it!



Thank you! I have the larger blue HEI distributor cap. I have a feeling I'll be calling you guys to make sure I've got this thing wired up right! Much appreciated!

Anytime!

you may want to grab a power pigtail too. makes wiring a little easier!
https://blueprintengines.com/products/hei-distributor-1-piece-power-tachometer-pigtail-harness

 

[AZMike75]

Anytime!

you may want to grab a power pigtail too. makes wiring a little easier!
https://blueprintengines.com/products/hei-distributor-1-piece-power-tachometer-pigtail-harness

Damn..wish I would have known that as I just placed an order for some break in oil a few days ago! Just ordered that pigtail thank you!

 

[DirtDonk]

Did you run the HEI through a relay? I read on here in a few spots that it's recommended.

I used a full painless harness and I have a bunch of relays but I can't remember if One goes to hei on that one. I tested the wire we use for power to coil on hei when starting on the 351 and did not get a big noticeable drop when starting. I Guess if you did a relay would assure a 12v to it.

There's a big difference in power source between the two, unless you're running an aftermarket harness too Mike?
A stock harness uses a resistor wire to power the coil, and that's the wire that many try to use to power an HEI distributor because it's so convenient. But since the HEI needs, and benefits from a full 12v, some opt to use the old resistor wire to trigger a relay, rather than sourcing a different wire.
It's more involved of course, but gets the job done.

Attac's Painless harness has no resistor wire, so does not need a relay unless it's desired. All the wires have a full 12v and there are plenty of extras to choose from.

Paul