Top Speed

[NES304]

cheers mate

[greyone]

anyone know what years are coarse spline e/g hq ute 3.55 would it be coarse or fine or either
regards mal

[CraigA]

It is most likely fine spline.

Commercials and V8's would have used fine spline axles/diff while 6cyl passenger cars would be coarse spline.

[oldgmh]

Almost all banjo diffs up to HX holdens were coarse spline, whereas HZ onwards were fine spline.

Perfomance cars like XU1's generally had fine spline banjo diffs.

Salisbury diffs are completely different again.

you should be able to pick up a complete coarse spline 3.36 or 3.55 quite cheap. 

have fun.   

[colt]

My old HJ 6cyl panel van was coarse spline, as I found out on many occasions.

[Sheriff]

I bought a 3.55 coarse spline about 6 months ago for $120.  Best to check for wear as some could have been abused.   Mine was a sad story, have owned my car for about 25 years and have not touched the diff.   Acting on the belief that a 3.55 would lower my cruising revs, bought one, took it to garage, told mechanic what I wanted to do, then went back later in the day to pick it up.   Young bloke doing job said "why did you want to change the diff, did it  whine or something"  I told him why and he told me the one he removed was a 3.55.   Wasted about $300 on labour.    Shows you never know.   Sold my original good diff for what the new one cost me though.
Still cruises the same       Cheers,  Mike.

[NES304]

Costly,,,,
I have a feeling it could be my points. I think their dirty and I haven't checked yet. Might try cleaning em before I change the ratio.

[MalFE]

I've just reterned from holidays to read this interesting post.
I purchased my car new in 1957 and the speedo never passed 80 mph no matter how hard I tried while it had the original motor.
Also had it up to 80mph on some of Sydney's main roads that were signposted 30mph.
At Lang Lang my car was much faster than 80mph due to minor internal mods and higher diff ratio.
Cheers,
Mal.

[Neil FE Van]

Back in the old days with no engine mods and using twin carbs and extracters we where always struggling to get 100 mph.