Its best to determine what the current cable length is. The part number and implied length is (was) printed on the cable sheath end perhaps on the helm end or on the motor end. Take a look at the cables to see if you can find the part number.
You can call Grady and ask and they are usually accurate but not always In any case one set should be about 2 feet longer than the other.
Thank you Sea Sick! Grady let me know, they are 26' and 28' However they are out of stock, so i need to find after market and make sure i get the correct Yamaha ends.
The lengths sound right but pull them out when you start the job and find the markings to confirm. Seasick has been there and follow his advice. You don't really want to try to make a different length work. Unnecessary complication. You don't need Grady cables either. Teleflex makes them for everyone and makes two grades - buy the better one.
No prob. Look up Seastar Extreme cables. They are good quality and are ( or were) a decent price.
You did mention throttle cables but I hope you plan on replacing throttle and shift since they are probably the same age.
I think this model is correct (call and verify correct part numbers.
XTreme™ 3300CC/33C Series Control Cable by SeaStar Solutions®. XTreme™ versions of the 3300/33C cables are offered for demanding applications in which a smooth feel at the control is essential. Cable has a 10-32 threaded terminal and a clamp-type fitting at each end. 3" nominal travel. 4"...
www.boatid.com
and they appear to be in stock. These cables are fairly common and most decent marine stores will carry them.