Will a modern battery fit the original battery box or do i have to change the box.? Thanks

Interstate and others still supply the original style Battery for the original Battery box.Check with your local Interstate Dealer.I believe they are NF29F #

  

Measure the length & width of your battery tray, then go to this site to find the group number:

http://www.rtpnet.org/~teaa/bcigroup.html

Armed with this info you should be able to get exactly the battery you need at your favorite parts emporium.

That list shows the 29NF Battery.13Lx5Wx8 15/16 H.Its an oddball because its long and narrow.Thats about all that will fit the original Tray.

  

The 29NF batteries were in the 56-57 TBirds. Did the passenger cars use them too?

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Yes they were Paul

  

If you are in the States there are many MFG's of the 29 NF battery to fit your tray, if not in the States or cannot find a 29 NF at a decent price and do not care so much about Original then several Import batteries are skinny enough to fit the tray and just shorter with many the correct heigth like a Mazda as an example. Strangely, these Import applications are also more powerful then the 29NF.

312T85Bird

What?