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#1
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8.5 10 bolt factory gear ratio
i was trying to figure out what gears were in my 72 ventura since i just got it going on the street
the id stamp really looks like JG theres a little hook like its a G but on of the codes is suppose to be JC for 3.08's but im running at 2350rpm@ 60 with my 275/60/15s and according to the calc thats pretty colse to 3.23s???? |
#2
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I take it you've never had the cover off?
Best way I always knew was to check the actual teeth count, to be 100% sure what you have. An educated guess would be 3.08 or even 2.73 for a 307 Ventura in 1972. If it's the original rear end, it might not be a bad idea to change the fluid anyway. |
#3
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Yes the best way to find out what gears you have is to remove the rear cover & count the gears to know excatly what gears you have. Being that old it may ahve been changed for any or many unknown reasons. Then Change the fluid to syn. as it is alot better for the rear end with some miles on it.
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#4
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What engine was in your Ventura originally. A Pontiac 350, auto would have had a 2.73,Chevy 6 had a 3.08.
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#5
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Not all Pontiac 350's got the 2.73 rear gear, the std gear for most all cars in the Pontiac line was the 3.08 then it was changed for options & other equiptment. A/C alwasy got a lower rear gear, but if you got A/C with the trailer towing pkg. you got the 3.23 as the rear gear. The choise of rear gear choise was really mixed up in the late 60's & early 70's. When I ordered my 73 GTO SD car I wanted 3.70 gears & that was not able to as no gear for the pontiac line was bigger then 3.42. The one I ordered & never came in was an A/C car & I had to get the 3.23 rear gear as that was the only one I could get with the SD & A/C, but if I would have wanted the 400 I could have had the 3.42's.
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#6
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All the 73-74 Ventura's I ever messed with had either 2.73 or 3.08
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#7
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Here is a page from the factory brochure showing the Ventura gear ratio.
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