From what I remember the only physical difference between a 51r & a 51 series battery is the orientation of the battery post. I personally wouldn't use it in place of the correct battery due to the stress on the batter cables/wires, as the wiring in these cars gets older it just gets more brittle, etc...But other than that I don't see any issues, as long as it has enough cranking amps to meet the requirements the car needs you should be just fine.

 

I had a similar issue with my Sol but my thing was one version of the battery was much cheaper than the other. I took the opportunity and replaced all my grounds with higher gauge OFC cable (Big 3 upgrade). Upgraded the starter hot/fuse box positive battery terminals to thicker OFC wire aswell. This allowed me to extend both the ground and the hot as far as i like. So now i can use either version of the battery and that saved me in the range of 50$ for the replacement. As a bonus gave me the piece of mind that everything is reliable and i shouldn't have any grounding issues in the near future.

The Knu concepts OFC cable, New brass battery terminal connectors, and copper welding connectors only ran me in the 25$ range. So i guess really i got payed to do the upgrade, and my starter works fantastic even in the dead of winter.

When it comes to replacing a battery as long as the form factor fits in the vehicle, it runs on the same voltage, and has enough cranking amps to start the motor. You can make pretty much anything work.

BTW advanced auto seems to carry both 51 and 51R, 51 seems to be the better value with higher CCA to the comparably priced 51R
All 51 and 51R

51 - 500CCA
VS
51R - only 410CCA

See same price different value

 

 

Im guessing you mean the plastic part that covers the positive battery terminal? That is there so that in the event of an accident the battery doesn't ground out against the hood and start a fire. Also to keep you from accidentally shocking yourself under the hood ( gotta watch them elbows ) . Some also have rubber boots that stretch over instead of the little plastic box which i prefer.

As far as the wiring upgrade its simple as pie, Just remove each old ground / power wire you want to replace. Take your new wire crimp on a copper welding lug the right size for what it connects to (i find a vice works best for the crimp). Run and cut it to the length you want and attach the opposite end to the respective battery post. I suggest soldering your crimps but lubing them up with di-electric grease and heat shrinking should prevent corrosion just the same.

You should really use new stranded OFC (oxygen free copper) cable for this job its mostly sold for stereo installs or welding. Compared to reusing anything old as the wire breaks down with time, and forms corrosion in its connections that cant be seen with the naked eye. Which can lead to all sorts of odd issues, and as i stated above the whole thing shouldn't cost more than 25$ ish if the pieces are properly sourced.

Just look up Big 3 upgrade on Utube, HT wont let me link the how to

Terminal connector for battery

Welding lugs for cable end to chassis

Knu koncepts OFC cable

Really no need for a DIY its just remove and replace.

Theres picture of my wires before and after in with my bay pictures in my thread here .
The OEM ones are the black ones in the early pictures, i replaced them with the neon ones in the later photos. The knu concepts rubber coating holds up fantastic under the hood, and stays flexible even in the coldest months.



:::: I Replaced ::::

:: + ::
Starter to battery positive
fuse box to battery positve
Both sharing a brass battery terminal connector

:: - ::
Battery ground w/ brass battery terminal connector to chassis
G4 trans ground to chassis
Valve cover ground to chassis
Cleaned thermostat housing ground
Added a ground from PS pump to chassis