Technical Length of Model A frame w/ spring behind

Can anyone tell me how much a model A frame needs to be lengthened to retain stock wheelbase using a 36 Ford rearend with spring behind? Or better yet, a measurement of frame that has been lengthened for spring behind? Will be retaining the stock rear crossmember. With some type of reference points? Any help greatly appreciated, thanks!!

 

I think if you measure from the center of the rear end housing to the center of the spring it's 7 3/8 inches. I cut my frame towards the rear, just after the taper on the bottom. I recently bought pieces of a Model A frame on Ebay, and have just begun the fitting process. Mine turned out to have a 7 1/2 inch cut probably to do with the width of the cut off saw blade. You will have to move body bolts around and drill some new holes, as some bolts will no longer line up. Good luck!

 

Yep, 7 3/8". That's what I lengthened my A frame for a spring behind 40 axle. Some will say 7 1/2" but it's really 7 3/8".

 

yep, I moved mine back 7-3/8" too,
here's an early build picture

 

Thanks a lot guys! Hey Paul, Looks like I'm doing something similar to your picture. Quick change and modified A spring. I don't really want a low car, and was thinking of trying no kick-up. How much is yours kicked-up and could you post a pic of how the car sat? I would really appreciate it.

 

Mine isn't kicked up (sorry I'm old and don't know how to post pictures) The spring behind configuration will lower the car a bunch, maybe 5 inches or so. I became concerned about the distance between the axle and the frame in case of bottoming. I raised my chassis an inch by adding a piece of rectangular tubing between the crossmember and the rear spring. I took a couple leaves out of the rear spring to soften the ride, and that lowered it some too. I may put a snubber at the contact point between the axle and frame.

 

rear cross member is two inches higher than stock.

 

Guys, another easy way to do this is to unrivet the crossmember, and slide it forward instead of backwards. Then reverse the bells so that the spring is ahead of the rear end, not behind. This way you don't need to extend the frame at all, just slide the crossmember forwards and reweld it in.

 

Thanks again guys!