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#1
05-08-2009, 07:40 PM
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"B" body ring gear vs "A" body ring gear
In a related post I told of blowing out the rear end in our Catalina at the drag strip last week. Finally had a chance to pull the back cover. The spider gears were the weak link, it appears that at least one of the spider gears lost a few teeth.
The ring gear is a 12 bolt [3.42 ratio]. The question is: Is the diameter of the big body 12 bolt the same as for other GM units ? The reason I ask is that I am considering putting a 12 bolt spool in place of the posi unit. I do have some other spider gears that can be put in but I don't want to race with a rebuilt posi unit and risk blowing it out. I am considering a custom built rear end for the Catalina but the spool would be a less expensive alternative and a quick-fix for the immediate time being. Any help is greatly appreciated, Jim
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65 Catalina sedan. Allen Thomas Performance 495. KRE Heads at 310cfm ported by SD Performance, ProSystems Dominator carb on ported Victor intake, P-Dude custom grind hydraulic roller, MSD ignition, 3.50 Moser/Ford rear. F-Glass front bumper by son Rob, rear by the old man and joint effort for trunk lid. 3950# w/driver. Best of 9.5761/139 on 175 shot, 6.01 /114 in 1/8. |
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#2
05-08-2009, 08:08 PM
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The ring gear is the same diameter, can use a 12 bolt spacer, but you can't use a 12 bolt spool. I had a 3.42:1 posi in my '66 GP and it ate up the rear running 12.1 @ 110 MPH. I'd put a 9 inch in it if you're looking to go faster. JMO
BTW, Brad says he'll have some new R&P gears soon to fit that rear......
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" Darksiders Rule "
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#3
05-08-2009, 09:33 PM
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misterp266: thanks for the reply. Question: If the ring gear is the same diameter on 12 bolts then why wouldn't a 12 bolt spool work ?
Thanks, jim
__________________
65 Catalina sedan. Allen Thomas Performance 495. KRE Heads at 310cfm ported by SD Performance, ProSystems Dominator carb on ported Victor intake, P-Dude custom grind hydraulic roller, MSD ignition, 3.50 Moser/Ford rear. F-Glass front bumper by son Rob, rear by the old man and joint effort for trunk lid. 3950# w/driver. Best of 9.5761/139 on 175 shot, 6.01 /114 in 1/8. |
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#4
05-08-2009, 09:40 PM
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Also, thanks for the news regarding upcoming R&Ps, that would be great.
Thanks, jim
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65 Catalina sedan. Allen Thomas Performance 495. KRE Heads at 310cfm ported by SD Performance, ProSystems Dominator carb on ported Victor intake, P-Dude custom grind hydraulic roller, MSD ignition, 3.50 Moser/Ford rear. F-Glass front bumper by son Rob, rear by the old man and joint effort for trunk lid. 3950# w/driver. Best of 9.5761/139 on 175 shot, 6.01 /114 in 1/8. |
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#5
05-09-2009, 09:43 AM
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Jim,
I admit I never tried it but I'm assuming the spool would be:
As far as I know only 3.55:1 gears will be available. Primarily targeted to street use. Not sure when, you'd have to ask Brad.
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" Darksiders Rule "
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#6
05-09-2009, 08:22 PM
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misterp266: thanks for the post. I also posted this question in the Race forum. The answer I got over there was that the difference is the ring diameter [which means the pinion is also different].
So you're right, a spool for a conventional [non-Ponitac big car] 12 bolt will not work in a Big Car Pontiac. Thanks for the info, Jim
__________________
65 Catalina sedan. Allen Thomas Performance 495. KRE Heads at 310cfm ported by SD Performance, ProSystems Dominator carb on ported Victor intake, P-Dude custom grind hydraulic roller, MSD ignition, 3.50 Moser/Ford rear. F-Glass front bumper by son Rob, rear by the old man and joint effort for trunk lid. 3950# w/driver. Best of 9.5761/139 on 175 shot, 6.01 /114 in 1/8. |
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