Diff Cover Drain

[MHISSTC]

So you recommend a cover that has ribs for strength, cooling fins for lower temps but are you against one that has preload which potentially strengthens the weak GM rearend?

The aftermarket cover for the GM isn't a performance advantage-unless you count potentially being more durable as an advantage. If you want to say it is a cooling advantage then whats the big deal since we allow radiators, coolers everywhere else.

Maybe I worded my post poorly.

I am in not against alternate diff covers for GM axles, or any platform for that matter, because I don't think durability is a performance advantage that can be measured in faster lap times. I think we should let diff covers be wide open. It also doesn't make sense to me that we can't do covers, but we can camber an axle which CAN lower lap times, but also introduces potential reliability issues by introducing a slight angle at the splines that increase wear. I would also venture to guess cambering a solid axle isn't something that should be attempted by your average CMC driver and that only those who are hiring expensive race shops to prep their cars are doing it. How much does it cost to have a shop camber a solid axle? Maybe we can get rid of that one along with the long overdue removal of the Ford 9" allowance?

What about being able to do C-clip eliminators? All the information and discussions I've seen say even though we CAN do that, we don't need to because all but one company builds them for drag racing and not road racing and that they really aren't needed anyway and are a waste of money. Can we get rid of this one along with the Ford 9" too?

Anyway, what I was trying to point out was that my recommendation to a rule change way back when didn't include diff covers with the preload feature that is commonly perceived as a potential performance advantage, even if it offers no such benefit in reality... ...and that got shot down back then. Has reliable information been shared widely enough to have changed perceptions since then?

Earlier in this topic the subject of wheel hop in the GM being the main culprit of reduced axle reliability was brought up. Will a different diff cover successfully combat this? I see there was a rule change request made to allow the Ford 8.8 in the GM chassis to supposedly bring about increased reliability to the GMs. Is the Ford 8.8 rear really that much better? If a different diff cover will do the job of making the rear end more reliable for the GM drivers, wouldn't that be a more cost effective solution to increase reliability than to allow a modified Ford axle in a GM? I'm thinking out loud here because I don't know.

[centerville]

Does this mean aftermarket diff covers?

6.29.4 Differentials or differential covers may have a drain plug added. "Differential covers may be
substituted".

[Supercharged111]

Yes, they're open now.

[BryanL]

Yes, they're open now.

So the rules are out. Guess I missed that. Where are the cliffs notes for changes.

[Supercharged111]

Changes are in red in the rules. Most were clarification changes. Big diffs also axed, years corrected for 5.3 swaps, aftermarket accessory mounts allowed for LS, ram air defined, angle iron can be welded to our k member to protect oil pan, and a couple others that escape me.

[Fbody383]

So $3k brakes, just not $3k rear ends... got it.

Sorry couldn't resist...

[Supercharged111]

So $3k brakes, just not $3k rear ends... got it.

Sorry couldn't resist...

Good point, but killing the diff rule doesn't impact people the way that killing the brake rule would.