Well, at the risk of sounding obvious, you need to either measure the old one and compare the two, or do like they did with the F150s in 1978.
Some of them shipped with the wrong dipstick. Since the problem was supposed to have been corrected at the end of 78, no one bothered to tell me why my brand new 79 was using oil.
After the shop checked for leaks a couple of times, and basically told me that it would clear up when the engine got broken in, I just went ahead and drove it.
I discovered that when I changed the oil, it would use the first quart in one tankful of gas. After that, it used no oil from then until the next change.
So, I just started running it one quart low.
Years later I happen on a service bulletin that mentioned that problem.
Their official recommendation was to change the oil and filter being sure to use the amount of oil called for with that engine.
Crank the engine and let it run for a few minutes. Then shut it off and let it sit for 5 minutes.
At that time, check the oil. If the dipstick showed it one quart low, replace the dipstick.
In the case of your engine, unless you have used a different pan, added an oil cooler, or special filters, you should be able to find the specs on how much oil it holds. Just put in that amount, and then check it with the stick.
If its wrong, take a file and make a mark where it should be.
Make sure the oil has time to drain back, and the truck is level.
As for the tranny, its a little more complicated, since its harder to change, and you have the converter which holds some.
In your case, I would find someone who has the same setup, and borrow his dip stick for a couple of minutes.
Check it with his, and then adjust yours so it matches. In that case, the transmission does not have to have the right amount, or be at operating temp. Just make sure the levels agree between the two.
J.