How much longer is throttle cable than shift cable? Mercruiser pre-Alpha

Is there a "rule of thumb" for how much longer a Mercruiser pre-Alpha throttle cable should be than the shift cable? Shift cable is on the transom plate and throttle cable below the carb.

I'm moving a 73 Mercruiser 140HP over to a different hull that's missing the shifter/cables and unsure how long the throttle cable needs to be, compared to the shift cable. I haven't installed the engine so I can't measure the length of throttle cable needed. Though, I was able to mock up the transom plate, old shifter and cables to figure out the length of the shift cable, 144".

The old throttle cable is 12" longer than the old shift cable, but the old cables had a lot of slop and droops so I don't trust getting a 12" longer throttle cable. My SWAG is that the throttle cable needs to be 18" longer,,, but that puts me half way between a 13 and 14' cable.

I guess if there is no "rule of thumb" I'll have to wait until the engine installed, but though I'd run it past the guru's.

BTW, I'm installing a Mercruiser 4000 GenII shifter (smoking deal) and ordering GenII shift cables.

Re: How much longer is throttle cable than shift cable? Mercruiser pre-Alpha

Maybe the "gurus" are busy

http://www.go2marine.com/productcenters/teleflex/teleflexCableMeasurements.shtml

For now this link might help

Re: How much longer is throttle cable than shift cable? Mercruiser pre-Alpha

What's improtant isn't whether or not it's longer, What is important is that it fits. You want to keep the bends in the cable as large as you can. A cable with sharp turns is harder to move and will wear out faster than one with out sharp turns.
Also, you don't want to attach anything to your cables. (Like wiring) Thats very important up by the throttle/shifter. but if you have to change them, you want to be able to just pull them out without having to dismantle the boat.