i know this has to be able to be done, since people run 4cyl tachs of 8cylinder motors

does anybody have any insight?

 

Everything is do-able, eventually.

The tacho would need the "pules signal" trickery inside reworked/replaced/fiddled to accept the 12 pulses versus the 6.

An instrument repair mob would do that for a fee.

 

Im actually looking to make thir run a 6cyl efi system

 

Easy on the Marelli just run off 1 coil.

Cal are you going to run the car distributorless? if so you will use 2x6cyl ignition units just run the Tach off 1 side.

 

I know on aftermarket tachs, there is a switch inside to change, marked 4-6-8. John's cars in Dallas does the factory tachs when you buy the small block chevy conversion kit from him, so it can be done. I am not sure if he would tell you how to do it if you called him or not.

 

If you are using a single distributor you can attach a tach signal converter from Dakota Digital to drop the pulses to what you need. Under $100.

 

Mustang six im checkinf that out right now

 

So it doesnr go to 12cyl. But could I just run 8 in and 4 out? Because its the same pulse adjustment

 

What kind of ignition system are you running? Knowing that, I might have another idea.

 

Planning on ussing a pre he ignition wuth an aftermarket pickup and msd 6al box

 

The 6al is only programmable for 4, 6 and 8 cylinders, meaning you will need 2 of them and run them 60° apart.

With the tach signal you can run a 6 cylinder tach off 1 of the 6al’s

 

Huh, I talked to a msd guy and he said they are running them on he distributors. Maybe he's refering to a different model I dont remember