Hi. I don't have the experience level of many of you on here, but in thirty odd years of hobby hot rodding I have never seen this... I brought a 1958 straight six, three on the tree f100 home last winter. The truck had a retrofit AMC 232 with Ford three speed manual transmission in it. I can tell this was at least the third engine it has had in it (go figure right?). I digress. It has what appears to be the original 9" rear end (fill plug in the back of the axle housing as apposed to the center section). Heres where it gets weird. Last winter while the weather was bad I did all the brakes. While I had it up I gave the rear end a spin to check the ratio.... 1.5 to 1 !!!!!! (rough guess marked tire/counted). Rubbed my eyes, did it again........ 1.5 to 1......Whaaaat? So for the time being since I had many bigger fish to fry with this old guy I left it to later in the project. Now we are at that point. Pulled the 232 this week to install a 272 Y block. Had my son over to help (my NEW back). We were talking about that gear ratio and I had him roll it around. 1.5 to 1 (rough guess marked tire/counted). He got the same thing. What gives? The tallest gears I am aware of for the 9" are if I remember right are 2:47 to 1. Any body have any ideas?? Should be great on the E way. The theoretical 172 mph top speed sounds exciting! (uh, yeah, good luck with that.) But ooof this will be a dog! I dont mind pulling the center section and having a gearset installed. I am just curious as to why/how this has this ratio. Glove box plate says 223 I-6/three speed manual/3:90 to 1.
Be a bitch to start off on hill with 1.5's in there. So when the tire makes one full revolution the driveshaft only turns 1.5 times?
Oh it gets better. I am going to run an Air cooled 3 speed Fordomatic that leaves in second gear! Luckily I live in the flats but still...
uh...you need to turn BOTH tires one turn, not just ONE tire. Or turn one tire, two turns. (something about how differentials work) It's likely a 3.0 ratio.
Both tires need to rotate to calculate the ratio. It isn’t even possible to get a ratio that low in the confines of a 9”.
Yay! Thank you. I will try that. It's an open so when I spin one the other tries to turn in the opposite direction. So make them both go in the same direction.
With a open rear end just turning one wheel since you have the spider gears that only gives you 1/2 of the ratio. 1.5 x 2 = 300. the sure fire way is to pull the pumpkin & count the teeth on the ring gear and the count the pinion teeth. and divide. You truck originally if it was a stick likely would have a 390 or 411 rear.
Just talking to my son (uh yeah, my NEW eyes too). He thought he was getting more like 1:7 or 1:8 to 1 so this is starting to sound more like what that tag is saying. Thank you guys!
back in 65 I got a 56 ford HTP. I borrowed the 352 interceptor engine from my mothers 59 ford car. that had a bad crusomatic trans. Put a stick behind it. and promptly blew the rear end . So I swapped rears with the 59 to get the nine inch. It was 300 to 1 ratio. Dad had a 58 truck the hyd clutch was leaking and engine shot. So I swapped rear chunks. I now had a 411 and dads old truck now had 300's! Maybe you have dads old truck?
For an unlocked rear end, mark the yoke and housing directly across from each other. Mark a rear tire and the fender directly across from each other. While someone is rotating the tire two full revolutions, count the number of times the yoke turns. Same procedure for a locked or limited slip rear axle except rotate the tire once. Sent from my SAMSUNG-SM-G891A using The H.A.M.B. mobile app
Don’t just spin one time, spin it ten times to get a more accurate count.... then move your decimal point one notch. Bones
Ive never seen a pinion yolk. Ive seen egg yolk. when it hatches what does a pinion look like? Now I have seen pinion yoke's LOL
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