LT1 conversion help for 1970 suburban

[SUBURBULANCE]

I am just finishing putting a LT1 motor with a 4L60E transimission in my 1970 suburban high top ambulance. I need to find a converter to switch the electronic pulse transmision into a cable drive so I can use my original speedometer. doing a little research i came up with Cable X which would definitely do the trick but i was hoping to spend less than $300 to do so. I was wondering if anyone had one laying around or had another recomendation for me