I was going to order a EDL-5673 (edelbrock catback) for my 1984 LG4 but it says on jegs that its for TBI I was just wondering if there was a difference?

 

The difference will be in the cat mating flange on the end of the I-pipe. Both LG4 and LO3 cars had 2.25" ehxuast but I am unfamiliar with LG4 cat hook-ups. Everything will bolt up but you may be required to modify the cat hook-up. I am sure someone will chime in to confirm or dissprove that the two connections are the same.

 

I have an LG4 As well get rid of the whole exhaust it is crap. Every last bit.
Get this:
$135 HED-68470 Shorty Headers
$99 HED-17470 Y pipe
$169 WLK-17495 Catback from dynomax
complete system for a budget
That will make that motor breathe fairly well