[Gromit]

My two cents is to check the part number on your oil pan first, and make sure you know the capacity - there were different ones on the 350s though I think all trucks originally came with the larger capacity one but sometimes over the years people may have put say a Camaro 350 with its 4 quart pan or a GM crate motor with the same 4 quart (what I think of as a car-type pan)..

Those motors generally take 5 quarts to put the dipstick at full (4 quarts for the pan, and one quart for the system, assuming a filter change)..

You didn't mention if it is right or left side dipstick - that might help. Also the part numbers are stamped on the dipsticks and the tube length needs to match the dipstick.

Funny how such a simple thing can be so involved but it makes sense to me..and of course having the right one is critical to your motor living a long life..

Here is a cut and paste of the GM crate 350 specs:

"Oil Pan / Filter / Adapter / Dipstick:
The 350/290 HP engine block has provisions for both right-hand and left-hand dipsticks. The 350/290 HP engine includes
a 4-quart oil pan Part Number 10066039 which has the "double bump out" for both dipstick designs.
The oil dipstick for the 350/290 HP engine for the right-hand (passenger) side of the block is 10190942 (indicator) and
12552920 (tube). If not using right-hand dipstick, use plug 09421743.
The oil dipstick for the 350/290 HP engine for the left-hand (driver) side of the block is 03951576 (indicator), and 03876870 (upper
tube). P/N 03951600 (lower tube) is installed at the factory. If not using left-hand dipstick, use plug 14091563 to prevent an oil leak."

So I'd like to add CDowns gave you good advice regarding the Dealer.. though Lokar should work if it comes with the tube and dipstick - I'm not familiar with them..