Since the rebiuld of my 383, I know I need to match my converter and gears to take advantage of the changes made to the engine. I'm not a racer, but I want all I can get out of my combo. Engine: 383- 9:1 CR Cast iron 906 heads, new srings and valves MP m1 dual plane OEM Carter AVS 650 CFM Camshaft: 268/284 MP purpleshaft Ignition: MP electronic exhaust: castIron HP manifolds, 2.5" w/ Flowmasters out to rear bumper. This car runs like a scalded cat on the interstate, but would like it to get some wheel spin on dry pavement, with 235 70 R 15's. Providing I have a fresh 727, what converter/ gear combo should I get.
You mentioned you Do drive on the interstate.....So much for the 5:13s and that 4,800 rpm COAN converter w/transbrake i was going to reccomend .Mopar Perfformance has some info in their catalog about Converter selection.Their recomendation for a 383/440 is a 175K converter for a cam.482" and up."K" factor i the way they ballpark stalls,being that each car will stall differently(weight,gear ratio,etc.) 145K=1900-2100 stall speed 166K=2250-2350 stall speed 175K=2400-2500 stall speed Now we all know that this ain't no 3,150 pd Duster, so....I think you will have to go to the next level,200K...which should be around 2650-2850.This should give good launch,but will not slip too much on the upper end. For gears i would say 3:55s -3:91 w/the 3:91 being my preference....(Why doesn't someone make like a 3:73 ratio or would that be too much to ask from the gear companies ) !whip The nice thing about the 383 is......it don't know it's a 383,....it thinks it's a 440.The bore stroke combination is perfect for lots of torque and QUICK revs.I have seen plenty of 383s beat up 455s,454s,etc....All they need is some low gears and a GOOD converter.All the major manufactuers have good ones,but some stand behind their product,w/ better customer service,which i'm sure some of these guys or GALS (I must be politically correct) can tell you a few HORROR stories about ! nervous Glen
Hi, I used to have a very similar 383 setup in my 67 Fury. Tight 11" converter (2600 - 2800 rpm) and 3.91 gears will get you rockin'.
If you are running a small diameter tire (under 28") or do lots of highway driving, I would put a 3.55 gear in it.
If you like, I can go to my trusty Moroso speed calculator and provide you with some rpm at certain speed/gear ratio info. Just post specific combo's you want info on.
Joined: Sun Oct 09 2005, 05:02PM
Location: ALLEN PARK, MI.
Posts: 2007
Yea, I was gonna recommend almost exactly what Nelson said! About a 2,500+ stall with 3.91 gears. I always go 3.91 MIN on a heavy C body! Your fairly mild combo would like the 2,500 stall. 2,800 is fine to! !thumb !driving Tony P.
Joined: Mon Oct 10 2005, 01:49PM
Location: Grand Rapids, MI
Posts: 421
YUp I'll second what everyone else has said, 2500-2800 stall, and 3.55's or 3.91's will turn your first gear into sideways sliding, tire melting fun !drive
OK, What about swapping the one leger for a suregrip. This is a 71 Fury with the stock original rear end. Can I replace the pumpkin with a suregrip unit. Do any of you have one?
There are TWO different sure-grips....58-68 and most 69s used a DANA Power-Lok which is the strongest and can be rebuilt by installing new clutches. The BORG WARNER non- rebuildable unit, which is not as strong as the DANA, was used in some 69s and all from 70-74. 1969 was a phaze in year for those sure-grips, so the later ones had the Borg Warners. You should have the 489 case in you're car.On the side of the housing it will be in raised numbers, you can't miss it Randys, Ring and Pinion and other gear vendors sell them new for around $900-$1,000 complete w/489 case and "NEW"Power-Lok setups that are much better w/any gear ratio,and all new bearings and it is completely setup and ready to drop in. What ever you do, when you do install one,use a "FRICTION MODIFIER" additive to the oil when you are filling the case, as this will prevent the clutches from prematurely burning them selves out. You could try looking under the trucks and vans in the boneyards,as some of these had sure-grips from 64-74..... !thumb Glen
Joined: Sun Oct 09 2005, 05:02PM
Location: ALLEN PARK, MI.
Posts: 2007
To go "even deeper" into Glen's theory, the 58' to 68' 8 3/4 gear "PIG" unit was in 2 styles. The 741 case was a cast iron design with a smaller pinion shaft. The stronger 742 case was cast STEEL with a larger pinion. They all used the CLUTCH DISC type locking diff. It is a rebuildable unit. In 1969 and up to the early 70's as Glen said, the 489 case was used. It to was cast iron but used a larger, "tapered" pinion with a crush sleeve to set the preload of the pinion.......not as GREAT of a design like the 68' and down pinions with SHIMS to keep the pinion firm in the case. Mopar began using the "CONE TYPE" locking unit. No wearable discs were used but metal cone shape devices with springs. These are said to NOT be rebuildable, but some HAVE done this with success.
The AURBURN SURE GRIP that is sold today (even for 68' and earlier) models is a CONE TYPE locker. Back in 97' when I purchased one, it was $400 bucks! Today? WHO KNOWS! Rebuild discs are available for the 68' and down units. !thumb Tony P.
Good News,Tony....The cone type sure-grip p/n R542051 is avail.from STRANGE ENGINEERING for $389,and this is brand new,not rebuilt. The master install kit p/n R5266 is $104 and has everything for a proper installation along w/USA made TIMKINN bearings. The ring and pinions are avail. for $189.00 RS03887355L...3:55s RS03887373L....Can you believe it...3:73s RS03887391L....3:91s Throw it in a degreaser,get out the case of beer(I would send you a case,but CUSTOMS frowns sending anything VOLATILE accross the line) Get a dial indicator,and they even include the instructions to set up the shims,etc. to get the correct gear patterns. For the grand total of about $682,this is all new parts,and away ya go! !thumb Glen
Rebuild discs are available for the 68' and down units. !thumb Tony P.