I need help identifying a Ford V8.
It has 6 bolt valve covers, which according to the internet means it's a small block or Windsor. It has the smaller size spark plug size that came around after 1973, I think...Here's what (little) I know:
My father in-law Marv's dad bought him this truck as a wedding gift, brand new in 1971. It's an F100 and originally came with a 302 according to the dataplate. Somewhere along the years (early 80s?), Marv "blew the engine" and swapped in a junkyard motor. He couldn't remember what engine it was that he put in, but he seems to think it might be a smaller engine than the 302.
My in-laws are now in their 80s and Marv's suffering some cognitive memory loss. The truck hasn't been on the road in about 12 years, and neglected maintenance finally sidelined it. We helped them move into a new house about 6 months ago, and after towing the old pickup to their new place that included a spacious shop, I've been picking away at getting it roadworthy again. The brakes were totally shot and required replacement of all shoes, wheel cylinders, master cylinder, hoses, a few sections of rigid tube, etc. With some fresh gas, the engine runs pretty well, but I want to do some basic tuneup items: cap, rotor, points, plugs. This is why I need to know what engine I have, because I believe these parts changed over the years. The spark plugs alone are not what I should have in the original 302.
My in-laws have given me the truck and I just want to be able to take them both out for a drive every now and then. Marv's memory loss is such that he can't remember what he said to you two minutes ago, but so many of the memories he can access are closely tied to this truck, Old Betsy. He's not capable of providing much help on the truck, but I do my best to narrate what I'm doing and include him in the process. It's amazing to see how engaged he is when we're in the shop poking around on this project. Help me get her cleaned up and roadworthy so Marv can enjoy some of his best memories. Here it is when we towed it to the new home a few months back:
Last weekend I drove it for the first time in at least 12 years. Pulled down to the house for a bath.
TLDR: help me identify this engine: where do I look for casting numbers? Are there other identifiers or tells that can at least tell me what tuneup parts I need to order?