i dont know anything about the classic engines.

have any idea? i'm thinking 289, but thats just because its blue, haha

 

it's a 289/302 windsor alright from what it looks.
the casting number is hidden under the starter, you can't really see it without removing the starter. Maybe we can figure it from date code as they stopped making 289s during 289 and started 302s. so if the engine is below 68 it's 289, 69 and later it's 302. 68 could be both.

The date stam is on the block, driver side, at the front just where head hasket is.
there's a little hump that should have a code like 7D13 or something like that. first is year, 2nd the month (a=jan, b=feb, ...) 'I' doesn't exist, so it goes h=aug, j=sep .. the last two are day in month

hard to describe whee it is but in your picture it's just about where coil wire (from coil to distr) and the distributor wire (from, distr to coil) cross. between engine and fuelfilter. that's the general area to search for it