400 to 727

If you are going that route... obtain an late 80's I6 flexplate and it's high torque starter and have it balanced to the flexplate for the v8.

I have a low milage matched starter and flexplate combo I was to use on my 390 th400 combo, but that will never be. If interested let me know I'll let them go for $50.00 plus shipping.   

Well the original 401 th400 flexplate has bolt pattern for the th400 converter, and will not bolt onto the TC727 converter. Also the Th400 flex plate is weaker design, many crack and break.

You will need to have the late 80's I6 flexplate balanced matched to the flexplate for your engine. So in removing tranny, you will have that opportunity to do so, while you are at the swap.

The the late 80s I6 has a less dished flex plate than previous years, to allow a Mitsubishi type gear reduction starter. Which is actually stronger than earlier oem v8 starters. Also they are smaller, so headers have better clearance and less prone to heat soak the starter.

The advantage is easier to find over the counter, and easier on battery when cranking performanced v8. It does remove the need for a ford starter solenoid, but you can make it function with existing solenoid, by jumper wiring the connection directly to the motor, in bypassing the integeral starter solenoid to the late 80s starter. The jumper needs to be around You may get away with 14awg, because of its very short length. I had to change the gauge... was thinking of power to engage motor directly, when there needs a kick out of the solinoid as well.

Edited by 304-dude - Mar/27/2023 at 2:16pm

Texas275 wrote: Will the 727 converter bolt up to the I6 flex plate?

Yep! Mine i had drilled for the th400 converter, but never had it balance for the V8 engine. It can be used on both trannys.

The last year the 401 was available was 1978, so the flexplates you have might be for a 360. They will fit, but you would want to have it balanced for your engine.