I have a 1968 with 300 I6 I have a automatic column from a 1970 and a c6 from a 1984 f150 my question is what flexplate do I need and torque coverter. Thanks for any help. Also will my drive shaft need to be shortened?

 

Can't tell you about the driveshaft, but you need to use a 300 flexplate and a C6 converter.

 

You should've gotten a C4 transmission but the C6 will work, but you'll need to find the bell housing for it which was only on the later trucks.

If you can't find a 300 flexplate, use one off a 302.

 

I don't know what the flywheel / flexplate balance is on a 300 inline 6 , but the 302 can be 28oz. or 50oz. So be careful there or you may end up with some bad vibration .____JIM



.

 

Pretty sure the 300 is internal balance. I know the 240 I had was so no imbalance on the flywheel. Have to use a 240-300 flexplate.

 

C6 had an integrated bellhousing, no changing it like on the C4s and FMXs. But being that it came from a F-150, it was behind a 351W more than likely, which means it has the 90* SBF pattern already. So it will bolt up as is.

But I do agree, a C4 would be better suited in this application. See if you can find someone in your area with one that would be willing to trade straight across for your C6. Race car guys would be your best bet. Or simply buy a C4 off craigslist and then sell your C6.

 

300 is an inline six so theoretically it's naturally balanced. Mine doesn't have any weights on the damper pulley or the flexplate. Just find a 300 or 302 flexplate and knock the weights off if need be.

Yup. Every C4 as far as I know will directly bolt on and it's a lot less of a power sucker than a C6. Can be built to be stronger too. C4 building is a big thing for drag racers. Mine's got Kolene steel plates, Kevlar bands, Raybestos clutches, and a Transgo shift kit. The thing is built for more power than my engine can ever give it.

 

Every C4 except the ones behind the small-block 6 motors. They use a whacky bell/flexplate/converter/starter/pattern.

 

Silly small six thinking it's good for something.

 

Got a 200/C4 combo in our 67 Galaxie 500. It's peppy! Straight pipe off the manifold, sounds like a tractor! And we had to cut a hole in the hood for the air cleaner to stick through. Everybody thinks it's got some big mean fire breathing motor. I don't know what it has for rear end gears, but it will spin a tire fairly easily. Haha