hey, just wanted to drop by and let you know that i also LS swapped a volvo and used the same type of circuit to get the tach working. I used a 1k resistor and the tach normally works. Sometimes in the cold it gets "stuck" at the highest value and doesn't fall back down when the engine RPM decreases. I might play with the resistor value a bit and see if i can't get it to work right.