I posted this in engine swaps and didn"t get a nibble. I am putting a 400 in my 78' F150 4x4 to replace the existing 351M. Now for the tough part. The truck is a 4 speed. The 400 caame out of a car with an automatic. Will the flywhell from the 351M work with the 400, or will I have balance problems?

Never a dull moment.,
Jerry

 

They should interchange. The 351M used a Windsor crank which has a 28 oz imbalance, the same as the 400.

Jason

 

The nice thing about having online parts places is the use of their application charts.

Unfortunately rockauto lists the 78 351 as a 351W which isn't correct beside the fact the listing is for 80's trucks. I'll have to let them know

Here is what I got from their site though.

No flywheel info just ring gear info

Flywheel Ring Gear Info for 351M

DORMAN Part # 04415
MT; 180 Teeth; 351M Eng {Gear-Up! O.D. 15.512" I.D. 14.518" Pitch 12 Width .440" Teeth 180 Chamfer None FORD OE# D7TZ6384AX}

ATP Part # ZA506
MODIFIED ENGINE; M.T. & 180 Teeth {RIng Gear Outer Diameter=15.512" Inner Diameter 14.518" Pitch=12 Width=.440" Teeth=180 Chamfer=NONE / OE# D7TZ6384A}


400 Info for flywheel ring gear.


DORMAN Part # 04415
MT; 180 Teeth {Gear-Up! O.D. 15.512" I.D. 14.518" Pitch 12 Width .440" Teeth 180 Chamfer None FORD OE# D7TZ6384AX}
ATP Part # ZA506

M.T. {RIng Gear Outer Diameter=15.512" Inner Diameter 14.518" Pitch=12 Width=.440" Teeth=180 Chamfer=NONE / OE# D7TZ6384A}