what gear
 

on the 72 i got tore apart right now its a longbed will be running 402bb mildly built and not sure if im going run a th350 or a 400.it will be used some for pulling a 18ft car trailer.will be running 275/60/15 tires what gear ratio should i run i want to pull good but i dont want the rpm screaming at 70 mph.when i had the 350/350 in it it pulled real good with the 3.08.i was thinking about 3.73 or 3.42.it will see alot of highway use just looking for the best performance all way around.thanks

My 3:73's scream at around 3000 RPm on the highway with 275/60/15 on all four corners. . Not too bad in my opinion.

I guess as a general rule, 3.73's are the perfect all around highway / town road / backwoods gears to have if you've got a tire size that's about standard. Personally, I've got 3.08's and 4.56's (night and day!) to choose from, and will probably go 3.08 as I do quite a bit of 50+mph driving. If I were to choose, and have a setup perfect for me, I'd go somewhere in between 3.73 and 3.08.

I haven't run the 3.08's on the interstate yet, but my goal is to be running around 2500-3000rpm at 80+ mph, whatever setup that gives me.

I would go with the 3.42 gears. The 3.73's are nice for towing, but 70 mph really turns the RPM plus how fast are you really going to drive it with out a trailer? 75-80? The 3.42 is a good gear , slightly better for highway milage, yet still low enough to pull decent, especially running a BB402. Just my 2 cents....

I would run the 342 with a posi. Best of all worlds especially if you find a nice overdrive trans. It will give you the low end and the high end with lot of potential inbetween.

Another vote for 3.42, thats what I just put in my truck.

I would also go 3.42, your BB will have plenty of tork & the 3.42s will show you about 72mph @ 3000 rpms on the 275/60 /15 tires. Good luck,crazyL:burnout:

3:50 F@rd 9" Posi "The only way to FLY"

:burnout: :burnout:

3.42 gets my vote too....that big block would still have enought toruqe for 3.08's to work good, but with a car trailer, 3.42's would be the way to go :bowtie:

thanks i believe i will go 3.42

70cst ive been waiting for the truck to bring me that 9in:D

woody i dont drive fast much but i was clocked a couple years ago at 104 in a 70 in nc with trailer/drag car.we woke up late and its a 2hr drive to track had to get there:burnout: :D

And y'all said I was crazy!
;)

had to get there hehe i wouldnt normally do that but the trailer is my cousins homemade i guess he got lucky and got the weight balanced right and my lwb with those hd leafs.it rides like a caddy loaded but will beat you to death when not i forget the trailer is there sometimes

104 mph with a trailer & drag car? thats just cruisin ,why didnt you open it up!:D crazyL

Not from our years, but My 96 has 3:42 and it pulls real strong (Vortec 350)...too much sometimes. Course mine has the OD...but when I had the 275/60 15 on it I would be doing about 2100 at 75. I had trouble that if it was even the slightest bit wet on the road, the rear would break loose unless you was a super old fart off the line.

th400 is one tough trans:bowtie:

Well I guess I am the odd guy out.....if you are building a big block with torque, I would say 3.08's are fine...the speed limits here are 60 and 70...I drive 10 over....at 60 my 502 is turning 2500....at 80 closer to 3200...thats gas guzzling RPM for any big block.

Comparitively speeking my Suburban with an OD and a 496 isn't far off....but it has 4.10's ...again with an OD.