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****** http-equiv="content-type" content="text/html; charset=utf-8">I have 74 F250 I was hoping you could tell me the ratio of Dana 60 an 70 also ratio of 4speed ZL no OD its all powered by 300 Canadian very low ratio 1''2''3''4 engine is running more like screaming at about 70 miles an hour should it be screaming
Look on the rear axle where the cover bolts on. There may still be a tag attached to one of those bolts. If it's there, clean it up and read the info. Somewhere it should have the ratio listed, like 3.73 or 4.10 (Can be listed as 3 73 or 4 10, sometimes even has an L between the first and second number)
If the tag is there, and you can't decifer it, post back with info printed on it.
I'm betting it's 4.10, and the trans should have a 1:1 (direct) 4th gear, since you say it's a non OD trans.
Another option is to jack up the rear of the vehicle (leave one tire on the ground). Use a piece of chalk, tape, etc. to place a mark on the tire and on the driveshaft. Count how many rotations of the driveshaft it takes to rotate the tire twice.
Someone may need to fill in how this works if you have a limited slip differential, since I think it's a little different.
AB, it would be number of turns of the driveshaft, for 2 turns of the tire, with one tire still on the ground. IE: 4 rev of DS for 2 revs tire = ~4.00, Most likely a 4.10.
With a LS, you would need to raise both wheels, and count the driveshaft revs for 1 rev of the tires, as both would try to turn at same time.
Dana 70's were offered with many different ratios, but 3.73 and 4.10 were quite common.
A V8 turning at 2500-3000 RPM on the hiway doesn't sound like it's wound up. A 300 turning the same RPM, sounds like it's turning more like 6000 RPM. This even truer when the big 6 has a solid mounted fan. I guess the blade pitch is more agressive on a 300, since they usually geared taller than a V8, to take advantage of the lower RPM torque of the I6.
Thanks I would like the screaming to shop 6000 rpm sounds about right. Would a OD 4speed be any better or EVEN 5 SPEED or is it the diff I have a lot of low end torque would like it to be top top end torque on high way ( DOING A BIG TRIP SOON LOADED UP ABOUT 3000 kilometre's across Australia N.S.W TO PERTH). Have a look on Google maps its going to be a very slow trip if I can't go faster then 60 mile's an hour
Thanks I would like the screaming to shop 6000 rpm sounds about right. Would a OD 4speed be any better or EVEN 5 SPEED or is it the diff I have a lot of low end torque would like it to be top top end torque on high way ( DOING A BIG TRIP SOON LOADED UP ABOUT 3000 kilometre's across Australia N.S.W TO PERTH). Have a look on Google maps its going to be a very slow trip if I can't go faster then 60 mile's an hour
Again, it's NOT a V8 so not built to "scream" built to tow n haul (in the bed or is it "table" as said down under). Some here had over drives, oem.
Yes changed rear gears would help. Both may be what U want.
I think you're on the right track by finding out what's in the chunk/pumpkin/rear differential (whatever slang the mates there use).
G'day again. I would like it to driver at 110kms an hour on the highway witch is the speed limit an not sound like I am still in second gear when I am in forth. Its reving at about 6000 RPM and it's a table top have pic's in album. I know its made for towing but I would like it to have more top end speed I am thinking of 5speed will do the trick or can the four speed be adjusted some how to get the engine running at 2500 / 3000 in forth at 110kms thanks
I highly doubt it's turning 6000 at 110 KPH. 4.10 rear gears would only put it up around 3000 @ that speed (roughly 70 MPH).
Hook up a tach, and be sure it's set for a 6. You might be surprised at the actual RPM.
AB - author of #5 in this thread, has a good formula for "final drive". You can use it to come up w/a good match for your needs. Cheapest or in some cases, easiest - factor to change in this FD ratio is Tire Size (tire size, tranny, rear gear, rpm...did I leave one factor out?).
I have to start with tire size cuz I wanna run a 33" ($600-800) when I can buy em. Also don't have the motor ('70s 250 I6) same reason, no money. But I CAN figure what gears and transmission to seek out. Lastly (not your case it seems) is the transfer case appropriate for the 70% off rd wrk the vehicle does. It's been working fine 4 these 27 yrs. of ownership but there's some wrk I could do alot easier others I can't do @all.
Hi Bill!
Good to see you again! Hey, don't forget he's down under (if it makes a difference).
W/a '74 F250 I wonder if he's got an NP435?
Does it go REAL slow in 1st w/ the screamin you mentioned?
Trani ratio: 6.69:1, 3.34:1, 1.79:1., 1.00:1 (1st, 2nd, etc)
That's a woods n fields truck, not hwy (3,000 mi trip U got commin). We had 1 here we took the doors offa. When it wuz time to hay, in this hill country, U could jump outta the seat (no 1 drivin) n as the truck headed down hill, run back n help the guys load bales and it wouldn't run away from you. Sometimes we hadta put a belt from our pants on the stering wheel to keep it straight but didn't often cuz then U lost ur paints!
Hey U eatin lunch down there - what time is it Patrick (930 am here).