gear swap question

i have a 88 ram with a 440 that i installed 3 years ago, runs great and plenty of power

question is i just bought some 3.90 gears and am on 31x12.50 procomps,im going from the factory 3.21

now for the front dana 44, all i can find is 3.92, will this work or will my driveline bind up, i also see some 3.91 sets for the chrysler 9.25

really i would rather have some 3.73, but can't find those for the 9.25 either

what should i do, i hate to say it, but ford 9 inch?  

Actually you have another problem too. There is a carrier break at 3.73/3.92 on the D44 so if you go to 3.92's you need a different carrier too. I can find no 3.73 for a 9.25 either at the moment.  Not sure about using 9 inch Ford because if I was going to swap rear axles, I think I would look for a D60 since you have a 440. One more possibility is the old Chrysler 8 3/4 rear end that like 9 inch has a removable pig and is a fairly sturdy axle too and it can be had in a 3.73 (Yukon makes them)  

Gears will generally tolerate a couple hundredths discrepancy without problems. But a 440 is probably too much motor for a D44. I would not use the 8 3/4 either. The 8 3/4 is more appropriate behind a Jeep 4.0 than a 440. I'd go with either the Ford 9" or  D60 (or even a 70).  

well im not wheelin the truck, more on the lines of going to the strip and picking on some 4 cylinders, 4 wheel will only be used in snow or when i need it, no mud runs or bogs,

the truck is 4600lbs and runs 16.1    2.27 60

the new hemi dodges can weigh from 4800-5600 depending on body stly and they are running low 15's or high 14's with the 9.25 so i was thinking mine would hold up if i rebuilt it

what about 3.55 i can get those for both the 9.25 and 44 right?  

3.55 is available for both and should work fine with your tire size. With an open diff, the 9 1/4 might survive. Locked, it probably will not.  

With 31's it should last. 30 years ago I had a friend that had a 66 charger with a with a VERY warm 383 with a 4.56 and a spool in a old 8 3/4 rear axle in it. (9.25 more or less replaced it) That car ran high 12's with slicks and the rear axle lived through it. The newer 9.25 in modern trucks seem to have pinion pre-load issues because they seem to have a above average failure rate for pinion bearings. If you plan to move much beyond 31's it will be time to consider a different axle. BTW, a 440 would be a LOT harder on a rear axle than any 5.7 hemi would be as 440's made low and mid RPM torque than 5.7 Hemi owner can only dream about. In it hey day they called it the 440 wedge and it was well known for its torque.  

http://www.racingperspectives.com/cgi-bin/store/imageFolio.cgi?action=view&link=Bret_Kepner_Photos/Domestic_Body_Styles/GIR_2007-05-08_Tuesday&image=BKD7-05-08_070.jpg&img=40&tt=&tfile=tn_BKD7-05-08_070.jpg        

here's a pic at gateway international raceway,

my 88 ram has seen a 19.3 with the stock 318 on 33inch bfg

since 05 i did a 440 motor swap and ran a 16.1 @ 82 with a 2.27 60'  this may seem to be a bad time for a 440 but keep in mind this is a internally stock 78 440 out of a truck with 8.2 compression ratio, around 425 lift cam(stock) and 3.21 gears with a 31 inch tire, now when i get around to putting in a voodoo cam, some 3.55 or 3.90, and some aluminum heads with a 75cc chamber over my 88cc chamber, this should bump compression to 9.2 and with a better profile cam and gears i should run a much better time

i don't like making guesses but im HOPING for around 2.2 seconds off my time, i just want to hit the high 13 mark Oh yeah it is a 4600lbs 4x4  

440ram:
http://www.racingperspectives.com/cgi-bin/store/imageFolio.cgi?action=view&link=Bret_Kepner_Photos/Domestic_Body_Styles/GIR_2007-05-08_Tuesday&image=BKD7-05-08_070.jpg&img=40&tt=&tfile=tn_BKD7-05-08_070.jpg        

here's a pic at gateway international raceway,

my 88 ram has seen a 19.3 with the stock 318 on 33inch bfg

since 05 i did a 440 motor swap and ran a 16.1 @ 82 with a 2.27 60'  this may seem to be a bad time for a 440 but keep in mind this is a internally stock 78 440 out of a truck with 8.2 compression ratio, around 425 lift cam(stock) and 3.21 gears with a 31 inch tire, now when i get around to putting in a voodoo cam, some 3.55 or 3.90, and some aluminum heads with a 75cc chamber over my 88cc chamber, this should bump compression to 9.2 and with a better profile cam and gears i should run a much better time

i don't like making guesses but im HOPING for around 2.2 seconds off my time, i just want to hit the high 13 mark Oh yeah it is a 4600lbs 4x4

The 440 is a strong motor when built properly. Given that you have 31 inch tires and no OD, a 3.55 might be best for your axles. Do raise CR ratio to to 9 to 9.5 but also do not have any illusions about running it on 87 octane after increasing CR. You might get by on 89 (it will likely need a bit more) but 87 would require such compromises in timing that it would seriously limit your potential. If 87 octane is a most have, do not raise CR and keep cam under 270 degrees or so too with automatic and a 3.55 axle ratio.

One more thing if 13 seconds is your goal figure on a 3.91 or 4.10 axle ratio, 10 to 10.5 CR, 93 octane, a cam with about 280 to 285 duration with about a 2500 RPM stall converter and maybe even a old 6 pack carb setup too if you can find one.