Which spark plugs?

[Unofficial]

So I'm taking my truck into a shop tomorrow to get some problems diagnosed, because I can't figure anything out for the life of me. Before I do, I wanted to make sure I'm running the right plugs. They seem a little short to me, and I feel like having too short of a plug will cause problems, so what are you guys using for plugs? What should the thread reach be?

[Irish_Alley]

part numbers would be good for this for comparison

[Unofficial]

part numbers would be good for this for comparison

They're AC-Delco Rapidfire plugs. I don't have the part number. I got them from autozone, these are it, but they don't have a picture. I just feel like they're too short.

EDIT: The part number just says "1." It says that on the plugs.

http://www.autozone.com/autozone/catalog/parts/partsProduct.jsp?skuDescription=Ac-Delco-Rapidfire+/+Spark+Plug&categoryDisplayName=Routine+Maintenance&fromString=search&itemIdentifier=22175_0_0_&productId=22175&sortType=&parentId=42-0&filterByKeyWord=spark+plug&isSearchByPartNumber=false&navValue=14200033&categoryNValue=14299999&fromWhere=&itemId=33-0&displayName=Spark+Plug&store=1767&searchText=spark+plug&brandName=Ac-Delco-Rapidfire

[Irish_Alley]

the treads should be about 1/2" that plug should be p# 10

[Unofficial]

Hmm, maybe they aren't too short. I guess I'll just take it in and see what happens.

[DnStClr]

For your 87, The plugs should be (AC Delco p/n) CR43TS. Gap at .035 inches  The threads are 14 mm and they (the plugs) have an extended tip.