Not a Buick but i will ask anyway. Anyone running 2.73 gears behind a big block? Her is my cituation. I'm building a 1970 el camino ss. It is set up with 2.73 gears in the factory 12 bolt. The engine is a big block Chevy 496 stroker making 576 hp @5400 rpms and 640 torque at 4500 rpms. I plan on running a 400 tranny and possibly converting it to a switch pitch with a 1800/4000 stall. It will most likely have the factory 14 inch factory wheels with 245/60r14's. Im shooting for a factory look and thats what it came with. The car will be a cruiser set up with some handling goodies. Any input on this combo? Looking for some opinions.
A 1970 El Camino is rated as a 1/4T truck. Add a posi, and bolt 500 pounds of lead pigs into the bed. You're gonna need 'em. :Brow: I have a 400/400/3.55 setup in my truck with that camper (in my avatar) and it will light up the right rear tire on hard acceleration. Since it is an El Camino, you could check here for more input- http://www.chevelles.com/forums/ The '71 Chevelles and El Caminos came with bigger wheels (15X7 instead of 14X6). I'd advise you to go to those 15X7 wheels or cheat and get wider SS wheels like Wheel Vintiques makes. I think it would look better with the same style SS wheels (just wider), but that is your call.
I usually run 3.73's with a 28 inch tire. I'm thinking the switch pitch combined with the short skinny tires may help out some. I'm not worried about getting out of the hole. I'm sure the 14's don't have a chance regardless of the ratio. I personally hate 14's but I'm trying to keep a stealthy stock look with this build. The torque numbers on this build should fry those tires at will. This will be my cruiser. When I want to do some thromping I will get the Buick out!:TU: I was just curious if anyone else has tried something similar.
If it rea makes 640ftlb you will be fine with the 273 , I drive a stock 72 455 every day with the stock 256 rear and it gets up and goes just fine with the stock converter im even runn a 275 60 tire
I do (used to be 2.56). Top end is limited only by aerodynamics, tire speed rating, courage, and the law. With big torque it's always amusing to feel the pull in fourth from 35 mph. Original owner swapped the 3.42 out for 2.56, then dumped the Muncie for a Super T10 with a 3.44 first gear. He towed his 5,000# boat for an estimated 100,000 miles this way getting "reasonable" fuel mileage. With this combo the car sixtys very fast and settles in for fast highway zooming. I call it the poor man's overdrive.
I drove a 2.56 behind my big block for many, many years. Big-block torque allows for tall gears. The only thing that sucked about off-the-line was lack of traction - I could NEVER find a tire that wouldn't spin, because I had tons of torque. If you have a dedicated track car with massive back tires, then a 2.56 might not give you a hard enough launch. But for anything on the street, a 2.56 is fantastic. You probably don't need that much converter either.
The factor here is NOT big block small block etc. Your camshaft, Intake, ignition timing etc anything that affects low end torque under 3000 rpm. Single plain intakes kill low end torque Big duration cams kill low end torque Over sized carbs 1000cfm will kill low end torque stock ingition may slow down the torque curve advance in the motor. ALLL these things add up... SINCE you have a lot of cubes that is always a plus on the torque side. Smaller duration size cam will always produce more low RPM torque below 3000 rpms than a long duration cam. THAT really is the only need for 2.73 gears (torque) SO I would say as long as you do not have a RACE motor your going to enjoy driving your car. A Burn out is a burn out once the tires spin traction is lost no matter what gear you have. Remember --- this is YOUR car. we can tell you all day long about what we think and like but you have to fit your car / truck to your needs. If you feel maybe the gears are dragging your low end down on the launch maybe you do have a pretty big duration cam try a 2000 -2500 stall that will snap the rpms up to where the motor will make more numbers above 300 ft lbs. Good luck have fun... wish I could afford a big cube motor like that. Jim
My 71 Chevelle BB convertible has the 2.73 12 bolt posi (original). I have a couple of gear sets 3.08 and 3.31 but I decided to stay with my original. I am running a 496 full roller, Brodix RR heads, 572 lift cam and 400 turbo. No problem with low end power (video) just a quick tick of the pedal 4400 rpm let off. This was with the stock converter, I tried a 3500 and it is just too much for what I want. I turned on a side street and kicked it to the floor and ended up with a 200 ft of rubber before I let off.. I tried this converter as I just had my trans rebuilt and did some modifications like six red clutches and koleen steels to the direct and intermediate. I just got a 2200 converter to install to make it more street friendly. I really like the 2.73..... Nelson https://www.youtube.com/watch?v=jGh9K99BCA4
Yah well if you have a torque problem with a 572 motor YOU GOT REAL big problems. lol. I would think you can have 4 cylinders down and still light them up....LOL. Jim
