Here's the info. on my 40. Perhaps it will help you.
The front tires do not rub the fenders when cornering. Since then I have installed the MT Products Lincoln brake kit on all for wheels. Using narrower front tires and/or removing leafs from your stock front spring may also enable you to "fine tune" your drop. The 40 Ford rear wheel mounting to wheel mounting distance is 59 and 1/2 in. I think the 41 is the same. The front axle is the same as a 41 Ford so I assume the front WMS to WMS is the same as a 40. I am sure you can find comparable radial tires to the bias ply I used.
My 1940 Build Info.
Front suspension; Magnum 4 in. dropped axle with matching Magnum dropped steering arms. The axle is 3/4 in. narrower than stock axle to allow better tire/fender clearance. Front spring is POSIE #2040 39in spring with reversed eyes. Also Posie front shackles.
Front has tube shocks and stock 1940 sway bar. Tube shocks were on th car when I bought the car in 1963. Bottom of shock attaches to perch bolt; top of shock attaches to vertical support that is bolted to frame rail. ( This was a kit that was sold many years ago and sometimes comes up on ebay.) I think similiar kits are available today from Chassis Engineering , TCI, etc.) I did not have to split the wishbones since the trans is stock 1940 trans with stock torque tube driveline and completely stock rear end with 3:78 gears. Rear spring is stock and not reversed. Rear shackles are replacements, but same as stock. Front tires are 5:60 x 15 Coker wide whites (2 3/4 in. white wall) on stock 15 x 5 1/2 early Ford truck rims (total rim width is 6 1/2 in.). Tire dia. is 25.88 in. Rear of car has BF Goodrich (from Coker) 7:60 x15 with 3 3/8 white wall. Rear tire dia is 28.66in. Rear rims are 15x6 from SOLIDS with 4 inch back spacing and 3 inch front spacing for a total rim width of 7 in. Bolt pattern of all wheels is stock 5 x 5 1/2 in. Bottom of front chin pan below grille is about 4 1/2 in off the ground. Because car sits so low two jacks are needed to lift front end in case of flat tire. One jack first lifts frame and then another jack goes under axle to lift wheel. One jack will not fit under the nose of the car as it is so low and you have to use 2 jacks so as not to crush the front sheet metal when lowering the car. On rear of car you need to first jack up the frame and then use another jack to jack up the axle housing in order to change a tire as it is a close fit. After installing the axle and front spring I had to shorten the tie rod by about 3/4 in and make the drag link about 3/4 in longer and rethread it 11/16-18 RH thread. When rewelding the tie rod, I cut it in the middle, inserted a solid piece of round stock, assembled the tie rod and welded all the joints. Right now the car "sits right" but the fluid from the rear end runs forward into the drive shaft since the car sits at such a rake. There is a baffle available for this problem but the rear and torque tube must be removed to install it. Since originally writing this, I have removed the rear end and installed this baffle and a new style neoprene seal in the clamshell. Clamshell is filled with cornhead grease. No leaks so far.
