Alternator/bat/cylinder head grounds

Please excuse any and all ignorance in advance as I have zero knowledge in electronics. I have 2 negative 1 gauge wires one shorty at 10” and one at 38”. I believe I am starting to loose current under long road trips as it seems harder to start and the lights have been flickering intermittently at night. The alternator is a 100amp kragen brand pile of crap that only has 7,000 miles on it. When I bought the heep there was no ground feed into the alt. The new alt only has one threaded screw coming out the back for the positive feed. I have I know 1 maybe 2 threaded holes in the rear casing of the alt. If I were to find the proper screw to fit and attach my negative cable to the casing and feed it to the battery would I blow my alt? Or is this the proper way to ground out an alt.
The jeep did not come with a battery ground to the fender. Would it be more beneficial to my electrical circuit to ground out the battery to fender or upgrade the chinsy cylinder head braided ground to the 1 gauge?
Application: renix 87 4.0l
Thanks,
Mike

The alternator should get grounded through the bracket, but adding one directly to the case shouldn't hurt anything. There should be a ground between the block and battery on the pass side, and then a strap from the back drivers side of the head to the firewall. That firewall strap is problematic, so perhaps replacing that would be a good first step. Adding another ground from the battery to the fender can't hurt.

You might also want to clean the battery terminals and replace the cables if they are corroded. The Renix needs to see a minimum engine rpm before it tries firing, so anything that gets the starter running faster makes a big difference starting. I prefer fine stranded wleding cable since it's nice and flexible.

Thanks for the input, my battery terminals are military style and are spotless. The cables are a 1 gauge welding cable, so the starter should have no trouble receiving a current. I'll try hooking up the alt casing to the -terminal and replace the cylinder head strap with 1guage and use the strap as a battery ground until I get another strand of welding cable.

Don't be fooled by looks at any connection, go through all of them one at a time, clean-em up. A redundant ground at the alternator and starter cases is a good idea also.

I replaced the starter on my wife's, no go. Clean all the grounds again, SHAZAM! She was pissy about the money I shelled out for a new starter, but in this case it wouldn't have been long anyway. She just skipped the opportunity to be stranded somewhere. LOL

Okay I'll replace the starter ground as well. It consist of the same chinsy braided material as the cylinder head ground. It looks completely fouled with oil and mud so I'm sure it’s in need of an upgraded replacement.