Rearend Question Regarding SBC - BBC Conversion
05-29-2011, 12:09 PM
#1
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Rearend Question Regarding SBC - BBC Conversion
I see many posts on here in regards to small block to big block conversions. My question is, since the factory big blocks came with a heavy duty rearend is there an issue in using a big block with a standard rearend? How many of you changed rearends when you did the conversion?
05-29-2011, 12:25 PM
#2
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The rear end itself isn't any different or heavy duty really. The only real change was the u-joints were retained with caps instead of straps which is pretty insignificant in the big picture. That won't be the part that breaks.
Depending on the use of slicks or real sticky tires...a stock one can last a pretty good while. I've had more trouble with the outer stub shafts breaking long before anything in the differential. Traction is the killer. For example...a buddy with a relatively mild high 12 sec 327 has broken 4 diff's in his '65. Since we put a 575HP 388" in it he hasn't broken anything. Now it just spins instead of hooking up! Problem with the 327 was it didn't have enough power to break the tires loose!
You need good solid Spicer ujoints, maybe later model 3" halfshafts...but easier and probabaly cheaper to just get new ones made out of even better material. Do a search here on *Shouldn't be here* for what he did to his C-3. After that the Tom's outer stubs will last forever...don't bother with cheap alternatives. Get good stuff.
JIM
Depending on the use of slicks or real sticky tires...a stock one can last a pretty good while. I've had more trouble with the outer stub shafts breaking long before anything in the differential. Traction is the killer. For example...a buddy with a relatively mild high 12 sec 327 has broken 4 diff's in his '65. Since we put a 575HP 388" in it he hasn't broken anything. Now it just spins instead of hooking up! Problem with the 327 was it didn't have enough power to break the tires loose!
You need good solid Spicer ujoints, maybe later model 3" halfshafts...but easier and probabaly cheaper to just get new ones made out of even better material. Do a search here on *Shouldn't be here* for what he did to his C-3. After that the Tom's outer stubs will last forever...don't bother with cheap alternatives. Get good stuff.
JIM
Last edited by 427Hotrod; 05-29-2011 at 04:58 PM.
05-29-2011, 03:22 PM
#3
Burning Brakes
How much HP and torque you fun will certainly have an impact on what rear end is right for the particular car, as will traction, transmission and how you plan to use it. That being said:
The 80-82 cars have an aluminium differential and there are many opinions out there on their strength or lack of it. Some guys have been okay with them, others like myself have adapted an older iron differential to that aluminium "batwing". The other issue is the carrier itself. If you do a search, I think you'll find many threads on what can be done to the inside of the differential to strengthen them.
I also agree with the comments from 427hotrod. When you're talking about conversions, rarely is anything as easy as it seems!
The 80-82 cars have an aluminium differential and there are many opinions out there on their strength or lack of it. Some guys have been okay with them, others like myself have adapted an older iron differential to that aluminium "batwing". The other issue is the carrier itself. If you do a search, I think you'll find many threads on what can be done to the inside of the differential to strengthen them.
I also agree with the comments from 427hotrod. When you're talking about conversions, rarely is anything as easy as it seems!
