[Shotimes] '89 SHO: New battery but still no power like lights, starter, etc.. WHY?

[HomeboyNorm@aol.com]

Hi all,

I and my friend did some work to his '89 SHO not too long ago.. We installed 
a whole drivetrain from a different '89 into the one my friend currently 
have.. 

After we had everything hooked up, we went to drop in a spanking brand new 
battery (and yes it's fully charged), and then tried to bump start the motor 
(for the oil prime-up).. No cranking, or anything, just nothing.. Then we 
noticed there were no interior lights on, so we tried the headlights but 
nothing too.. 

Battery connections were checked carefully, and they are on good and tight.. 
This '89 didn't have any problems before with its previous drivetrain.. And 
then it got parked for months before we dropped in a different drivetrain.. 
Now the electrical gimmicks to be worked out are really 'bugging' us.. 

What could the cause be? We're like the idiots when it comes down to 
electricity.. I was thinking to check the power at various places with a 
digital voltmeter, but then we don't have one to use with.. 

Any feedbacks, advices, and/or suggestive fixes will be GREATLY appreciated.. 
HELP!!

Thanks, Norm

'89 red/grey SHO
'93 black/black MTX SHO (probably a 14.99 or better car after an upcoming 
tune-up)
'93 red/grey ATX SHO (parting out)
'99 black/characol Mustang SVT Cobra (13.68@104.6mph stock on a 2.2x sec 60' 
with the crappy soon-to-be bald tires - Also a 13.72@104.2mph to back it up 
with)