Holley sniper efi on a 383

[74delta]

So I'm pulling the trigger and ordering the holley sniper master kit. Does anyone have any input on things I may run into? I already have the electronic ignition and I'm running a holley 650 carb. Any pointer would be great. 65 300 383 auto.

 

[Davea Lux]

So I'm pulling the trigger and ordering the holley sniper master kit. Does anyone have any input on things I may run into? I already have the electronic ignition and I'm running a holley 650 carb. Any pointer would be great. 65 300 383 auto.

You need to be sure and mount the fuel pump below the fuel tank or it will likely give you trouble. Be sure have a clean tank to start with. I would mount a fuel filter before the fuel pump and topside before the EFI unit, that should be in the instructions. (If you have not done so already, be sure you have an electronic voltage regulator) How you tune the unit will depend on what you are starting with for an engine. If this is a performance build and it is reasonably fresh, you can be more aggressive than with a stock 100k engine.

Dave

 

[furious70]

Definitely replace all rubber fuel lines. I ruined my first efi pump with rubber coming from the rubber line from sender to hardline. A filter before the pump may cause it to struggle, do a 100micron vs 10. You can do a 10 after the pump.

 

[74delta]

Definitely replace all rubber fuel lines. I ruined my first efi pump with rubber coming from the rubber line from sender to hardline. A filter before the pump may cause it to struggle, do a 100micron vs 10. You can do a 10 after the pump.

Good advice. What did you do about a return line?

 

[furious70]

My car was from CA so had vapor return line that I used.

 

[74delta]

My car was from CA so had vapor return line that I used.

Gotchya

 

[twostick]

Don't route any of the wiring harness near ignition wires, the alternator or the charging circuit. The system is very sensitive to RFI/EMI. ( radio frequency interference electromagnetic interference)

If you are using a regular magnetic pickup distributor instead of the Holley dual sync distributor, make sure you use a shielded twisted pair cable connected as close to the pickup as possible. Cut the leads as close to the pickup as possible and still be able to make the splice. Slide the stainless braid back far enough so that when you slide it back out over the splice, it covers right up to the pickup. Run the shielded cable away from the distributor, coil, plug wires alternator etc to the ECM and ground the braided shield at that end, preferably to the same ground as the ECM.

This will give you a cleaner tach signal which is critical to make it run properly especially at idle.

When I did my 493 years ago the magnetic pickup wires inside the distributor were picking up so much RFI from the rotor arcing to the towers that instead of the tach signal trace on the data log being a single line like a pencil, it was about a 1/2 inch wide or more which equaled about 3000 rpm. The ECM didn't know whether to **** or steal second. Running an MSD box makes it even worse because of the multi strike. Even shielding the cable right up against the pickup didn't clean it up 100% but it was only about 25 rpm wide instead of 3000 and it behaved properly.

Kevin