The distributor pickup is the same between small and big-block electronic distributors. The difference is in the vacuum advance canister.
In fact, if you don't mind drilling out and replacing a rivet, the physical pickup coil itself will swap in from a later Lean Burn application (which did not have mechanical advance). However, pickup trucks larger than half-ton used mechanical/vacuum advance well into the mid-'80s so they're still relatively easy to find in junkyards.
RockAuto ships to Canada, but the shipping can be murder. You should be able to find it, or its equivalent, at your local non-NAPA parts store (Echlin ignition is gaaaar-bosh!), though it's not likely they'll have it on the shelf. Ask the man for Standard Ignition LX102 or equivalent, and tell him you don't want the cheap one! Spend the extra for better quality, particularly on ignition stuff.
Remember, us local-parts-store guys are the people that patronize your place of employment too. Plus, if you have an issue there's a lot of value in being able to deal person-to-person. RockAuto might refund or replace the part, but they won't cover any of the shipping costs and you won't get credit until the original manufacturer decides the part was defective.
If your local parts guys are total hammers, try Amazon dot ca with the same information. They're usually on par with, if not cheaper than RockAuto and they have a Canadian distribution system. Not only will their shipping be faster, if you have Prime or order enough to cover the minimum, it'll also be free... but please, try the local guys first. Keeping your money in your community is more important than you might now think it is.
aboard the Mopar train.
