WTT/WTB 8 3/4 Center Section 3.73 to 4.10
- Thread starter fzmax
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moparguy440
Member
i have a set of 3:91 posi but the price is high as there hard to come by around here but ill take $650 for them not counting shipping last time i shipped a pair it cost me $94 dollars and some change why not take the 3:23 gears and buy a 3:73 ring and pinion and build a posi unit for them i'll post some pics of the one i have with 2:97 out of my boys dart works just like a posi and i"ve built them for dirt cars pushing close to 800 hp and never broke them boy run his on the street behind a 408 before i built the 3:55 for him was in the car for 8 months and blew up motor and never had any problems out of the posi unit
j061093409
1970 Dart Swinger 340 Reg
I have 3.91 in 741 factory case - looking for 3.55 surgrip. what case in your open 3.55?
In Hartford, CT
no rush as have short trip to help son. next week ok
In Hartford, CT
no rush as have short trip to help son. next week ok
fzmax
Well-Known Member
Moparguy, thanks but $650 is a little rich for my blood.
j061093409, I am pretty sure they are in a 489 case, but I'll check tomorrow and post up. I'm not crazy about the 741's but I would consider it. I'm running a four speed and with sticky tires I would worry about the pinion snapping.
j061093409, I am pretty sure they are in a 489 case, but I'll check tomorrow and post up. I'm not crazy about the 741's but I would consider it. I'm running a four speed and with sticky tires I would worry about the pinion snapping.
805moparkid
Slant and AFX Guy
you'll snap a pinion on a dana before you snap one on a 741... the 741 has a tapered pinion where the 742,489, dana 60 have a step near the bearing seat area... its a weak point just like stock cranks... And its a bigger diameter than a dana (think a 8.25 is close to a dana though)...
the 741 is more than strong enough for anything, its the spiders that blow up... but gears are getting very hard to find...
motorhead446
Well-Known Member
last i checked the 489 is a tapered pinion. it has been a while since i checked though.
fzmax
Well-Known Member
Just verified, the 3.55's I have are in a 489 case.
Thanks. I was pretty sure I was correct, but don't have one apart I could verify.
805moparkid
Slant and AFX Guy
thats exactly my point... see how the 741 is straight with no step? yes the 489 and 742 have a bigger pinion but they all run the SAME YOKE... which means effectively THEY ALL HAVE THE SAME SIZE PINION... dosn't matter if its 4" in diameter by the head... that step is the weakest link...
fzmax
Well-Known Member
So I was searching the interweb trying to find examples of broken pinions where the yoke attaches and had no luck. I didn't find any examples of broken spiders either, but what I did find was examples of ring and pinions missing teeth which is the only way I've ever broken one. Then there was this quote from this website:
"and i was also gonna mention he is only running a 741, should be running at least a 742 or 489 case..." (that was you kid)
In any case (pun intended), I'll stick with a 742 or a 489, but still may be interested in your 3.91's for now j061093409. Ping me off line with a price and maybe we can meet somewhere in the middle.
"and i was also gonna mention he is only running a 741, should be running at least a 742 or 489 case..." (that was you kid)
In any case (pun intended), I'll stick with a 742 or a 489, but still may be interested in your 3.91's for now j061093409. Ping me off line with a price and maybe we can meet somewhere in the middle.
74DartSwinger360
The Brat Pack
fzmax what is your price on the open 3.55's in the 489 case?
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