70chev Posted April 27, 2011 Share Posted April 27, 2011 Alright so I finally got under my car and decoded the rear axle and it turns out I have 256 gears. Should I switch to 273 gears? My car has a turbo 350 and It looks like I am going to have a 355 engine; imput please.......... Thanks, Wayne Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted April 27, 2011 Share Posted April 27, 2011 I don't think you are going to see much change between the 2.56 and the 2.73. What is your plan for your Monte? How will the 355 be set up? Good mileage cruising, mild performance, high performance? They all go hand in hand with gear ratio choices. Quote Link to comment Share on other sites More sharing options...
70chev Posted April 27, 2011 Author Share Posted April 27, 2011 I just use it as a driver.....would like to take it to the track once or twice for fun. Also, do a lot of freeway driving. Quote Link to comment Share on other sites More sharing options...
72 LS5 Posted April 27, 2011 Share Posted April 27, 2011 If you do a combo of city/highway, you may want to consider a 3.08 gear. I put that in my 85 Monte with a 355 and turbo 350 trans with a mild converter. You may not be in the fast lane on the interstate with 3.08, but you can keep up with traffic w/o going over 3k rpms, and you'll still have some off the line dig. Plus, with that ratio, you can really tweak it with tire size if you aren't 100% happy with the results. 2.56s are tall gears, but when I found out the original gear in my 85 was a 2.29, I almost fell off my chair. Before I changed to the 3.08, I would only use 2 gears down the track - it sounded like a powerglide car! Quote Link to comment Share on other sites More sharing options...
Andy's Auto Posted April 27, 2011 Share Posted April 27, 2011 I have found the best beat versus neat gear to be a 3.31. Decent cruise, great tire smoke. But if it your daily driver, 2.56s are about THe most gas pump freindly gears out there. I pulled my 3.73 12 bolt out of my 68 Velle for 2.56s last year, more so because of a 25 inch tall BFG. Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted April 28, 2011 Share Posted April 28, 2011 Andy must be getting old. I would go no less than 3.73, and I prefer 4.10 or 4.56..... Quote Link to comment Share on other sites More sharing options...
502ci Posted April 28, 2011 Share Posted April 28, 2011 I'll suggest a 3.42 gear, I have it in two of my other vehicles and it seems like a decent compromise of both mpg and performance...my Monte has a 4.11 gear and I would not suggest that unless you plan on putting in an overdrive.. Quote Link to comment Share on other sites More sharing options...
72MC Posted April 28, 2011 Share Posted April 28, 2011 I have found the best beat versus neat gear to be a 3.31. Decent cruise, great tire smoke. But if it your daily driver, 2.56s are about THe most gas pump freindly gears out there. I pulled my 3.73 12 bolt out of my 68 Velle for 2.56s last year, more so because of a 25 inch tall BFG. Well, I think I will have to side with Andy on this one. Based on Wayne's post I believe he still wants to maintain a highway cruiser as well as some stop light to stop light. With a warmed up 355 and th350, 3:31 gears are sweet. Still great on the highway doing 70+ mph and some decent grunt on the street from a stop light. Don't think I would go with 3:73 - 4:56 for highway use doing 70+ mph in a 3 speed. But that's me. The biggest problem with 3:31's is that they don't make them anymore. I have a set in my El Camino and a spare set that I doubt I will part with. I would suspect 3.23 or 3.42 would be the way to go. Don't get me wrong. I absolutely love my 4.10's in the Monte but I also have OD. - Dave Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted April 28, 2011 Share Posted April 28, 2011 someone is making the 3.31's I forgot who started doing it Quote Link to comment Share on other sites More sharing options...
72MC Posted April 28, 2011 Share Posted April 28, 2011 Sam, that would be good news. About time. - Dave Quote Link to comment Share on other sites More sharing options...
502ci Posted April 28, 2011 Share Posted April 28, 2011 Yeah, several months back I also heard someone was making the 3.31 gear. Quote Link to comment Share on other sites More sharing options...
Andy's Auto Posted April 28, 2011 Share Posted April 28, 2011 Motive Gear is still making the 3.31s. Quote Link to comment Share on other sites More sharing options...
72 LS5 Posted April 29, 2011 Share Posted April 29, 2011 I have 3.31s and love them. BUT, on the highway I cruise at 3000-3200 rpms and I'm in the slow lane doing just shy of 70 mph, getting past by campers - everybody does 75++ around here. I have 255s 60 15s, btw. I wouldn't want to go on any long trips with that gear and no overdrive, but its great for winding backroads, around town, and a quick blast on the highway. Running a 28 inch tire certainly would give you another 4-5 mph on the highway. I'm keeping my 3.31s. Quote Link to comment Share on other sites More sharing options...
MCfan Posted April 29, 2011 Share Posted April 29, 2011 I have 3.31s and love them. BUT, on the highway I cruise at 3000-3200 rpms and I'm in the slow lane doing just shy of 70 mph, getting past by campers - everybody does 75++ around here. I have 255s 60 15s, btw. I wouldn't want to go on any long trips with that gear and no overdrive, but its great for winding backroads, around town, and a quick blast on the highway. Running a 28 inch tire certainly would give you another 4-5 mph on the highway. I'm keeping my 3.31s. According to the rimsntires.com comparison tool, changing from a 255/60-15 (27" tall) to a 275/60-15 (28" tall) will increase your speed 3.5% at any given rpm. I also run a 3.31 with 275/60-15's on the rear and my engine is taching exactly 2800 at 70 mph(actual via gps). In fact, that combo of gear and tire gives you exactly .025 times (or 1/40) your rpm in mph (if your transmission's high gear is 1:1, of course). For example, 1600 rpm on the tach is 40 mph, 2000 is 50 mph, 2400 is 60 and so forth. So, you can run 75 mph at 3000 rpms (if you can afford the gas, that is). Quote Link to comment Share on other sites More sharing options...
zmanabba Posted April 29, 2011 Share Posted April 29, 2011 Andy I went to Motive's web site and couldn't get any prices. Do you have a ballpark price. I have never used their stuff before how is the quality? Thanks, David Quote Link to comment Share on other sites More sharing options...
zmanabba Posted April 29, 2011 Share Posted April 29, 2011 Wayne, If you decide to get rid of those 2.56's let me know. I might be interested. David Quote Link to comment Share on other sites More sharing options...
Ian Posted April 30, 2011 Share Posted April 30, 2011 Andy I went to Motive's web site and couldn't get any prices. Do you have a ballpark price. I have never used their stuff before how is the quality? Thanks, David Summit caries them. I have their 3.42's in my 12 bolt. Quote Link to comment Share on other sites More sharing options...
72MC Posted April 30, 2011 Share Posted April 30, 2011 Motive Gear is still making the 3.31s. I just went through Motive Gear's catalog and the only 3.31 ring and pinion gears I see being made are for Dana and Ford 8.8 rears. Still not convinced anyones making 3.31 gears for GM rears. Summit does not offer 3.31 gears for GM 10 or 12 bolts either. If I'm wrong on this, I should would like to see part numbers. - Dave Quote Link to comment Share on other sites More sharing options...
cudax Posted May 1, 2011 Share Posted May 1, 2011 When I was looking to upgrade mine I couldn't find a supplier for 3.31's either. So, I found a nice used original set on e-bay and after I purchased them, I found a 70 12 bolt with 3.31 posi near me in perfect shape and bought that too. Long story short and back to the point, if someone is producing them I would like to know who too. Mike Quote Link to comment Share on other sites More sharing options...
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