I recently bought a group 51 battery for a '63 Avanti, but now wonder if I should have gotten a 51R (same except terminals reversed). I need to decide while I still have time to exchange it.
The 51/51R battery is smaller and much lighter, is of modern technology, costs less, and lasts longer. What's not to like about a 51/51R (unless you're dedicated to originality)?
The pic below shows a 51R installed in a '63 Avanti. Everything on this car looks well done, so I figure he knew what he is doing. He has re-positioned both hold-down posts and has made a bracket to move the fender-side post forward. It looks like these changes have made using a 51R battery a better choice than a 51, although it looks like either could be used.
The 3EE battery is (LxWxH, inches) 19.3125 x 4.375 x 8.875
The 51/51R battery is ........................9.374 x 5.0624 x 8.8125
The 51/51R is ~0.7" wider -- should be no problem
The 51/51R is ~ 0.75" lower in height -- no problem
Comments?
--Dwight