The 1950 flathead was rated at 100HP, with a cubic inch displacement of 239 and a compression of 6:8:1. The later engines were better than the early blocks and if your engine is running and doesn't have a cracked block as the flatheads were prone to, you might get $100-125 for it. There are still alot of rodders who like the flatheads myself included and you'll have to hook up with one either on E-bay or locally.