The AR100386 is listed with the 4240 at $648,,the AR100385 is listed with the 4440 at $569,, I am wondering if the AR100386 has a lobe for a lift pump drive..other than that I am not sure of the difference,,I know the early 404 cams were improved to help with the oil pump drive gear wear,, I don't have any info on valve lift or duration,,I have seen them used in other 404 applications, even in 4020's..so it will work out for sure,,even better if the price is right. I have an old 4430 like yours here that was bought new by the family,, it was the first new Gen sold at a dealership 75 miles East of me,,they quit milking back in the 80's and the old Gal sat in the barn for years,, now the sons want to bring it back,,and it is in sorry shape now,, I just did the AC system, hydraulic pump and lights,,waiting to see how far they want me to go for now, the interior is "Gone",,it's been repainted years back and not a good job then,,it's so Ugly you can hardly look at it,,,I won't paint it for them but I will do anything else that they want..and like some one on here said.."If it cast a shadow it can be restored"... When I restore one I like to go clear down..inside and out..seals sychro's, axle bearings, engine, Hydraulics and components..paint then wiring..and it takes a lot of time and money for a job like that. A few years ago I did 2 2510's for a guy like that I did all but the paint..and it was a pricey job..I never did see how they turned out but they ran and shifted nice with no leaks..