Originally Posted by dinosaurfan

Whoa, slow down here guys.....where did you get some of these ideas ? I think Jowilker is correct in that a 410 core would be worth 500$, tops. Everything but the crank is ordinary stuff. But as far as being 'not THAT much better than a 390', well, it is. About 100lbs-ft better. And lets stop with this story about mercury threw a 428 crank in their 390- WRONG ! Mercury developed the 3.98 stroke crank. They wanted to get extra torque for the large luxury barges of the day, and the 410 gave 80-100 lbs-ft of torque over a similar 390. Ford was busy developing the 427 Cammer and 482 starlifter engines, and paid them no attention to them at all. The 1U casting # is correct, it would be in 66-68 full size Mercs. It is not identifiable from the outside. Now about the flywheel or flexplate, don't worry about at all. They are available new for the same price as 390 gear.Try Pioneer for flexplates and McLoed for flywheels. If your shop doesn't know how to order the right one, just get the regular 390 unit. Your machinist can balnce it to work fine. ( You are having the rebuild balnced, aren't you ?) After Merc did well with the 410, some Ford dealers started installing the 410 crank in 406 blocks (makes 428 inches) and dropping 427LR heads on the engine- that is how the 428CJ engine was born. Pressure from dealers and HotRod magazine finally prompted Ford to offer the engine as a production item. C'mon now, am I the only guy who remembers this stuff ? DF

Originally Posted by Towman4u

The real Mercury 410 did not use 390 top end! I know from experience. Stumbled upon this motor when my dad bought a 69 f100 back in the early 80's. We thought it was a Merc. 390 until the thermostat stuck closed. Went and got one for the 390, (you guessed it) it didn't fit. It was way TOO small. Thats when we found out from a friend (ford mechanic) that it was a 410. He told us at that time it was a 390 that used the same crank, rods, intake and heads as a 428. My opinion is if Mercury created the stroke, then they most likely created the intake and heads as well. Don't believe what's on Wikipedia about the Mercury 410. This motor is insane. It would make a monkey out most of ford's run of the mill motors. I'm not talking about BOSS, COBRA JETS, 427 SOHC. Rated at 330 hp and 465 lbs ft torque. Most likely under rated, it had every bit of that hp and torque. It felt like it had more than that but then again it was in 2wd short bed f100 with 4 on the floor and 411 gears!