rear gears

[old-tank]

Will there be any real or ‘seat of the pants' acceleration gain if I replace 3.4 gears with 3.6 gears? My 55 Century CVT has been leaking from the front torque tube seal so I need to pull the rear out anyhow. The car with dynaflow and engine (322) is totally stock except for a ‘mild’ cam (can’t find the spec right now). It starts well and idles smoothly and has no drivability problems except it is more sluggish at lower speeds than one of my other 55’s with original engine; BUT from 50 to 100 mph it really hauls….that’s nice but that is not where I do most of my driving. According to my calculations the engine is turning 2400 rpm @ 60 mph with 3.4 gears and will be turning 2550 rpm with 3.6 gears. Will this gear change help or should I look for other ratios? (this would be the cheapest and easiest change for me since I have a 55 Special 3.6 rear with speedometer gear)<BR>Thanks in advance<BR>Willie

[56Roadmaster]

Hi, no you probably will not gain much at all you need to look at the cam spec and see where the torque band is greatest then go about matching every thing else. Plus the dynaflow has a variable pitch torque converter which is designed to give even acceleration without wheel spin, you may want to consider going to a LOWER torque range cam because you are not able to turn the engine RPM enough to make the one you have effective. Scott

[Guest]

Hi,<BR>The difference between 3.4 and 3.6 is not great but you will feel it "in the seat of your pants" irregardsless of the cam specs. In fact if the cam tends toward the higher rpm range as you suggest it will be even more noticeable than with a more "stock" cam. Since it sounds like you have the other gear and it's coming apart anyhow I'd go ahead - you won't be dissappointed but with the small ratio change probably also won't be estatic! Ideally you need about a 3.9 gear for liveable streetable performance. Anything lower than that gets old if you go very far (been there) lots of fun in short bursts lots of noise in longer trips.<BR>Ed Green

[The Old Guy]

I am sure that someone out there with a straight eight will trade you the 4.1 from their car for your 3.4. That will give you a decided boost from the lights ,but as the earlier post stated, it gets a little buzzy on a long trip.

[old-tank]

Thanks for all the input so far. Found the Specs on the cam: Bought it from NW Buick Performancein 1993 (what happened to that company anyhow?); the part number was CS-2114; lift .454 on both int & ex ; duration 260 on both int & ex; power range 1000-5300 (on their stock cams they list a power range 800-4800) They told me it would work well with dynaflow and since they are out of business I can't even send them a nasty-gram!<BR>Willie

[Bill Stoneberg]

Hi Willie,<BR>I have a 4.11 rear end out of my Wagon sitting here collecting rust.<BR>It needs a 3rd member but you can have the rear end for the gears if you want it.<BR>I can even deliver next time I go to SA or if you come to the meeting on the 3rd you can get it.

[old-tank]

Finally got it swapped and working...the verdict: the torque tube leak is fixed; no new noises or problems and the seat of the pants acceleration is better..feels like stock with low speed driving and still hauls at higher speeds.<BR>Now I have a 3.4 gear set to collect dust or sell.<BR>Willie