[Firemunky]

SO we (my son and I) finished the swap of the blown 350 to blown 454 last Saturday. Drove it around all week to breakin. It was time to see what it could do. We went to a long stretch of basically abandon road. Stopped...brought er up to about 3500 and in on the gas and out on the clutch. Well not what I wanted....the MT street slicks hooked nice...we went about 6 feet and ripped 6 teeth outta the GM 4.10 ring gear! I already ordered a new Richmond set......My questions is with the 350 with 600hp we dumped it like this hundreds of times with no problems. Not even having had this BBC to the dyno yet I'm guessing 800hp so do I need to lauch differently so as not to rip out the new gears or should this have been sort of expected from this increase of power and stock gears? It is a 12 bolt series 4.
Thanks in advance.
Craig

[El Toro]

Be happy that you got several hundred runs out of a stock rear end, it was time. If you don't have a spool in it now, might be a wise next move.When you're doing the gears check the upper control arms and cross member thats a week point.

[Wally]

Originally Posted by Firemunky

SO we (my son and I) finished the swap of the blown 350 to blown 454 last Saturday. Drove it around all week to breakin. It was time to see what it could do. We went to a long stretch of basically abandon road. Stopped...brought er up to about 3500 and in on the gas and out on the clutch. Well not what I wanted....the MT street slicks hooked nice...we went about 6 feet and ripped 6 teeth outta the GM 4.10 ring gear! I already ordered a new Richmond set......My questions is with the 350 with 600hp we dumped it like this hundreds of times with no problems. Not even having had this BBC to the dyno yet I'm guessing 800hp so do I need to lauch differently so as not to rip out the new gears or should this have been sort of expected from this increase of power and stock gears? It is a 12 bolt series 4.
Thanks in advance.
Craig

I say that was a good run on the stock GM gear and I would not even think twice about replacing it with a good used one. The early gears are plenty stout. Tourque is what killed it plus sticky tires and maybe a touch of axle wrap, better known as wheel hop.

[gspan1830]

That 4-Speed might be a weak link too.

[427L88]

Expected on a weak set. Even with a new clutch pac/springs and axles , oem 12 bolt is marginal with a rat under pressure.

Did you expect it to hold up under that much power? Is the driveshaft a Denny's HD/Nitrous or oem? If not, you best get one with the big 1350 ends. Is it a Muncie 4 gear? You best get an AGE M23 then.

The blown rat was the cheap part dude, in case you hadnt reckoned that yet!

Or get the slicks off and learn to drift the thing.

[VinceS427bb]

check your axles also
the driver side like to snap in 2 after some hard clutch dumps with plenty of torque
you don't want that to happen,
don't ask me how i know either...