Rear end identification
Thread Starter
5th Gear
Joined: Jun 2013
Posts: 5
Likes: 0
Rear end identification
UPDATE -
So im pretty positive they are 3.55s (just by turning the input shaft) and im pretty pumped. I think itll be good for my setup but i want to know what you guys think. Here what im runnin;
400 SBC
96-99 Vortec heads (rebuilt)
comp cam (.477 in, .480 ex, cant remember duration) (1600-5800rpm)
edelbrock vortec intake dual plane air gap (1500-6500rpm)
holley 750 carb
stock pistons and crank
Muncie M21 four speed
will all this work with the 3.55s or should they be bumped to 3.73s or 3.90s?
Thanks!
So im trying to figure out what my rear end is.
http://www.corvette-world.com/corvet...tification.php
^Iv been here but its not too informative b/c i dont think this is the original rear end from the car.
The number on the diff reads - OH243 8F1
theres a space between the OH243 and the 8F1 and right before the 8 theres a little symbol that sorta looks like a lower case "w" but it may just be an imperfection. Now the the car is a '74 but OH is only designated for the later years (from what iv seen) and its either a 3.55 which i may keep or a 3.08 which ill probably dump. So can anyone tell me what all this means? also there is a 3899149 on the driveshaft carrier, but i dont know if that means anything, thanks!
So im pretty positive they are 3.55s (just by turning the input shaft) and im pretty pumped. I think itll be good for my setup but i want to know what you guys think. Here what im runnin;
400 SBC
96-99 Vortec heads (rebuilt)
comp cam (.477 in, .480 ex, cant remember duration) (1600-5800rpm)
edelbrock vortec intake dual plane air gap (1500-6500rpm)
holley 750 carb
stock pistons and crank
Muncie M21 four speed
will all this work with the 3.55s or should they be bumped to 3.73s or 3.90s?
Thanks!
So im trying to figure out what my rear end is.
http://www.corvette-world.com/corvet...tification.php
^Iv been here but its not too informative b/c i dont think this is the original rear end from the car.
The number on the diff reads - OH243 8F1
theres a space between the OH243 and the 8F1 and right before the 8 theres a little symbol that sorta looks like a lower case "w" but it may just be an imperfection. Now the the car is a '74 but OH is only designated for the later years (from what iv seen) and its either a 3.55 which i may keep or a 3.08 which ill probably dump. So can anyone tell me what all this means? also there is a 3899149 on the driveshaft carrier, but i dont know if that means anything, thanks!
Last edited by 74_Corvette; Aug 8, 2013 at 02:31 PM.
Drifting
Joined: Jul 2002
Posts: 1,995
Likes: 110
From: Garland Texas
The last 3 numbers should be 143. That's just the case casting number, means nothing. On the left side of the housing just below the stub axle and above the strut rod bracket is the casting date. It will be a letter, then 2 or 3 numbers. That will tell you when the housing was cast.
Never assume the gears in the diff match the gear code. Turn the driveshaft and count the revolutions while watching the tire turn exactly one revolution. That will tell you the actual gear ratio.
Mike
Never assume the gears in the diff match the gear code. Turn the driveshaft and count the revolutions while watching the tire turn exactly one revolution. That will tell you the actual gear ratio.
Mike
Race Director
Joined: Oct 2000
Posts: 12,682
Likes: 3,135
From: Shamong, NJ
"OH" is a 3:55 likely from a 78, or possibly a 79 Corvette.
8F1 is probably the assembly date, June 1, 1978. The "8" being 78, the "F" for June and the "1" for the first of the month. I believe the "W" is for the Warren MI. assembly plant.
"OH" was also could indicate a 3:07 rear, from a 1980, but the 80 used the "bat wing" rear, which is completely different than the 79 and earlier rears.
8F1 is probably the assembly date, June 1, 1978. The "8" being 78, the "F" for June and the "1" for the first of the month. I believe the "W" is for the Warren MI. assembly plant.
"OH" was also could indicate a 3:07 rear, from a 1980, but the 80 used the "bat wing" rear, which is completely different than the 79 and earlier rears.
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