If I understand correctly, you dismissed the BBC V8 from the '86, but are wondering if you should swap the 250 from the '70 in for the original 235?
With the proper gears, the original equipment could pull down a house, but I don't think you'll keep up with current highway speeds without making changes to the drive train. That's about 25 mph faster than it's originally set up for. Is that why you're hoping to build up the straight six?
