Manual trans + 4.8 + Stock rear = Disaster?

[explosive]

Hey,

Budget is tighter than expected this year so i'm looking to do a light and basic setup while i acquire everything for a nice turbo build. I'm thinking stick my cammed 4.8 vortec into the car and toss a 4 speed manual behind it. I think it'd be an enjoyable little cruiser. This would also save me from going to an 8.8 immediately. Car currently has a 305 in it, im assuming it has a 7.5 in the rear. I figure a lumpy 4.8 would make 300ish at the rear tire on a good day ? Seems like on a street tire the combo should survive so long as i dont beat it to death.

What are the thoughts ? Eventually I'd like to just do an 8.8 w/31 spline shafts/carrier. this is my first go with chevy stuff.

 

[olds307 and 403]

At least upgrade the spider gears, especially if you plan on dumping the clutch. They are soft and explode under pressure, ask me how I know.

 

[GuysMonteSS]

It all depends on how you drive it.
The harder you drive the faster it will break.
Guy

 

[Streetbu]

The engine isn't the issue. The stick is. I blew my 7.5" up three or four times with my Muncie and a heavy right foot and only 300hp....

 

[81cutlass]

A stock 8.8 might not last either. The stock fox 28 spline axles aren't hard by any means. Plus they are 4 lug. Unless you go with a sn95 style 5 lug axle that's wider.

A 7.5 will last if you drive the car like normal on 15" tires. If you put anything sticky and go to the track its life is numbered.

 

[explosive]

The engine isn't the issue. The stick is. I blew my 7.5" up three or four times with my Muncie and a heavy right foot and only 300hp....

Ouch, thats not too promising lol.

A stock 8.8 might not last either. The stock fox 28 spline axles aren't hard by any means. Plus they are 4 lug. Unless you go with a sn95 style 5 lug axle that's wider.

A 7.5 will last if you drive the car like normal on 15" tires. If you put anything sticky and go to the track its life is numbered.

I’d just be rolling around on a basic street tire/rally wheel setup for now. Im leaning toward the wider sn95 axle. Might see if i can get axles with the chevy pattern but then i gotta make sure i can put brakes on it. The cars a wagon and i love the rally wheel look. As for strength im a prior long time ford guy who’s put many 8.8’s through the ringer lol they have always impressed me - my uktimate goal is 650-700’s through an 80e and id trust a 31 spline setup on a tire so long as its through an auto and footbraked.

 

[jlcustomz]

I've had a built 7.5 posi unit for years behind a 5.7/ t56. Being put together right helps, better parts help. Some units are better/less worse than others. Luck helps. Having suspension not hopping & jarring it helps. Not dumping the clutch when traction is good makes a life or death difference.

I'm not saying my bfg 255/50 18's aren't bald as fuuk from spinning them, I'm saying it requires some care. Absolutely no hot pavement 5000 rpm clutch dumps.

May consider the explorer rear/ southside machine swap one day if there is a factory posi 4.10/11 ratio available.

 

[Bonnewagon]

I had a Pontiac 400 with a 4 speed Saginaw and 7.5" rear. No problemo 10 years. BUT- I had 3:23 rear gears and street tires.I was not kind to it and it lasted. Crummy ratio gears like 2:41 will cause strain and break easier.

 

[Streetbu]

Mine was a "built" 7.5" with Richmond gears professionally installed. That was the first rear end I blew up. Running a mild 300hp 350 and a Muncie M21. I drive like an *ss so I'm not blaming the rear end. Had 255/60/15 Bridgestones on it. Kinda soft. Ended up just putting used S10 gears in it every time after. Got to where I could do the gear swap in 1.5hrs... LOL