flywheel interchange

[Darren]

I'm swapping the 360 out of my '71 F100 for a 390 and plan on keeping the 3 speed. Would it be wise to keep the existing 11 inch clutch, or should I go to 12 With a larger flywheel? Thanks.

[1972hiboy]

If you are going to do a clutch now is the time to do it. not after you get the engine back into the truck and couple months down the road. I did this swap with my 390 install. went to the bigger clutch and flywheel. id say go for it.

[fordman]

11 inch is enough for that trans. I think 12 inch is for larger transmissions.

[tnlprt]

12 inch clutch is for higher performance use.....or heavier duty

Did you have to change the bell housing to one with the hump to use the 12 inch clutch

[fordman]

12 inch clutch is for higher performance use.....or heavier duty

Did you have to change the bell housing to one with the hump to use the 12 inch clutch

I knew it was something like that.i couldnt remeber exactly.

[1972hiboy]

everything bolts in. no need for a bellhousing. you bolt up the flywheel and the pressure plate and clutch, put it all back together

[Madman]

Isn't the flywheel itself the same for a 360 and 390? I'm pretty sure they are.

[fordman]

Isn't the flywheel itself the same for a 360 and 390? I'm pretty sure they are.

Yes i would think so. They are the same block and the same bell pattern.

[Madman]

That's what I thought, the 390 had a bigger clutch but the flywheel was the same...like a 289 and 302, until they changed the teeth count near the 80's.