71 MONTE 4 YA Posted November 25, 2011 Author Share Posted November 25, 2011 Hey guys I took the cover back off of the BOP rear end that I have and emptied the fluid out and found these numbers on the pinion gear 12A41 GM SS. If I am correct that means that there are 12 teeth on the pinion gear and 41 teeth on the ring gear meaning I have 3.42 gear ratio. Correct? There were these numbers also 894703 220. Any help is always appreciated. Thanks... Rodney Quote Link to comment Share on other sites More sharing options...
72MC Posted November 26, 2011 Share Posted November 26, 2011 Yes, you have 3.42's. 41 divided by 12 is 3.42. That 12A41 GM SS should be on the ring gear outer edge. Too bad you don't live closer, I still have a stock BOP (Pontiac) 10 bolt outfitted with posi 4.33 gears, drum backer plates and axles included that I would let go for fairly cheap. Probably would need an overdrive tranny though. - Dave Quote Link to comment Share on other sites More sharing options...
714024SPEED Posted November 26, 2011 Share Posted November 26, 2011 The BOP 12 bolts were 10 bolt housings that were drilled out for the 12 bolt cover from GM.I dont know why they did this? The rear you bought should hold up fine. Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted November 26, 2011 Share Posted November 26, 2011 It is actually an Olds rear. It has a 10.3 inch ring gear and it is different than any other GM rears. It is great that it has a 3.42 gear in it. It should be a nice cruising gear. Quote Link to comment Share on other sites More sharing options...
71 MONTE 4 YA Posted November 27, 2011 Author Share Posted November 27, 2011 It is actually an Olds rear. It has a 10.3 inch ring gear and it is different than any other GM rears. It is great that it has a 3.42 gear in it. It should be a nice cruising gear. Thanks Mike. Now I have to get a shorten driveshaft. Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted November 27, 2011 Share Posted November 27, 2011 How long of a drive shaft do you need? I have one that came from a monte with a TH350 and a 12 bolt chevy rear. Quote Link to comment Share on other sites More sharing options...
71 MONTE 4 YA Posted November 27, 2011 Author Share Posted November 27, 2011 How long of a drive shaft do you need? I have one that came from a monte with a TH350 and a 12 bolt chevy rear. To be honest Mike, I do not know. But I was told that it had to be like 3 inches shorter. I don't want cut mines just in case I might need to go back to stock. Quote Link to comment Share on other sites More sharing options...
bobsmc Posted November 27, 2011 Share Posted November 27, 2011 rodney, you need to come see me i had a bop in my red monte before i built my current set up i have evrything you need bob Quote Link to comment Share on other sites More sharing options...
71 MONTE 4 YA Posted November 27, 2011 Author Share Posted November 27, 2011 rodney, you need to come see me i had a bop in my red monte before i built my current set up i have evrything you need bob Bob Pm me with prices Quote Link to comment Share on other sites More sharing options...
71 MONTE 4 YA Posted September 3, 2012 Author Share Posted September 3, 2012 Sorry everyone I know this is an old thread but I wanted to ask everyone if i could get these perches to work on this BOP rear that I got back in 2011? Here is the Ebay Listing Quote Link to comment Share on other sites More sharing options...
71 MONTE 4 YA Posted September 11, 2012 Author Share Posted September 11, 2012 I got the perches in the mail today and I really thing I'm going to be all set with these. I laid them on the axle and it's going to be a perfect fit. Here is a picture of the actual spring perch: Quote Link to comment Share on other sites More sharing options...
monte70car Posted September 11, 2012 Share Posted September 11, 2012 Rodney how well does the coil fit? To me it looks like the coil will need a large opening at the bottom. I also see where it says offset so this will change the location of the coil spent from sitting above the rear end to either in front or behind the rear end. Quote Link to comment Share on other sites More sharing options...
71 MONTE 4 YA Posted September 12, 2012 Author Share Posted September 12, 2012 Rodney how well does the coil fit? To me it looks like the coil will need a large opening at the bottom. I also see where it says offset so this will change the location of the coil spent from sitting above the rear end to either in front or behind the rear end. Rob it sits in front of the housing just like the original on our Montes. I haven't tried a spring on it yet. Quote Link to comment Share on other sites More sharing options...
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