If your car has the 8" rear end, roughly 300hp if you're not brutally abusive with it. If it has the 6.25" rear end? Not much more than a stock 2.3 or 2.8 puts out.
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1976 Ford Mustang II Ghia: 302 with a 600cfm Edelbrock carb, Edelbrock Performer 289 intake, Dynomax Blackjack headers, 2.5" exhaust with Flowmaster Super 44s. RJS 11-gallon fuel cell, C4 tranny, chrome 16" pony wheels, fuzzy dice, brown vinyl half-top, and painted in the tackiest color ever (harvest gold, that's why I call it "The Goldenrod").
Also have a 2003 Dodge Ram (lightly modded daily driver/tow rig/office/dining room/home away from home/workshop... I call it "The Big Blue Dawg".)
If it has a removable cover on the rear of the axle, too bad. If it is solid in the rear and the carrier drops out of the front, you have an 8". The gear ratio should be on a tag on one of the carrier bolts. If not, roll the car forwards slowly one tire revolution and count the number of times the pinion goes around. (helps to mark it with chalk)
If you've got an 8", it'll look like a mini 9" pumpkin. I'd say that chances are that yours is a 6 3/4 with the 3:18 gear. I ran my 78 for a few years at the strip with a 6 3/4 and a modified 302 and had no troubles at all. i later upgraded to the 8" unit for a differant gear ratio [3:40] and still ran it till I sold out. I wasn't pushing any major power but had alot of fun. Friends of mine ran and still run these small rears in their minisport circle track race cars and run em up to 8500 rpm with no modifications to the rears although most of the trouble you'd see would be from a takeoff at the strip and snapping wheel studs if any.
The 74-78 Mustang II came with the 8" with the 4 lug and the 3rd member interchanges with that of the old Mustangs. I had put a 3:55 in my 65 when I first built it out of a II.
If it has a removable cover on the rear of the axle, too bad. If it is solid in the rear and the carrier drops out of the front, you have an 8". The gear ratio should be on a tag on one of the carrier bolts. If not, roll the car forwards slowly one tire revolution and count the number of times the pinion goes around. (helps to mark it with chalk)
Thats what I got then-
So I can deliver a bit more power to it then.right?
Mine was able to handle 308hp but I went with hardned studs but I just went ahead and changed over to a ford 9 inche lincoln versilles rear end with disc brakes.
the 8'' rear end, came also in the 1974 mustang II, my car have a 2.3 engine, so don't know which rear end came in the first 74 stangs. I'll check if i have luck enough to have a 8'' rear end, but any of you knows will make it more easy
the 8'' rear end, came also in the 1974 mustang II, my car have a 2.3 engine, so don't know which rear end came in the first 74 stangs. I'll check if i have luck enough to have a 8'' rear end, but any of you knows will make it more easy
If yours has the 2.3 then it has the 6 3/4 rear... only the V-6 came with the 8inch diff..... my 74 was a v-6 and it had a 3.55 gears open 8 inch diff
Mine was able to handle 308hp but I went with hardned studs but I just went ahead and changed over to a ford 9 inche lincoln versilles rear end with disc brakes.
What kind of fabricating did you do to be able to bolt that in?
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2004 Mustang Cobra Convert 1977 Mustang II (work in progress)
If yours has the 2.3 then it has the 6 3/4 rear... only the V-6 came with the 8inch diff..... my 74 was a v-6 and it had a 3.55 gears open 8 inch diff
Not all 2.3 cars had the 6.75 rear, my old '74 had a factory 2.3/4spd with an 8"
Quote:
Originally Posted by Dave
Just for my own information, when did the 8" come with a 4 lug axle?
Dave
The first-gen six cylinder cars had 4-lug 8" rear ends too, but it was on the larger bolt pattern shared with the Falcon instead of on the bolt patter shared with the Pinto and fox-chassis cars.
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1976 Ford Mustang II Ghia: 302 with a 600cfm Edelbrock carb, Edelbrock Performer 289 intake, Dynomax Blackjack headers, 2.5" exhaust with Flowmaster Super 44s. RJS 11-gallon fuel cell, C4 tranny, chrome 16" pony wheels, fuzzy dice, brown vinyl half-top, and painted in the tackiest color ever (harvest gold, that's why I call it "The Goldenrod").
Also have a 2003 Dodge Ram (lightly modded daily driver/tow rig/office/dining room/home away from home/workshop... I call it "The Big Blue Dawg".)
This is in regards to the question about the 9" Lincoln. I installed a 9" complete rearend from a 1980 Granada in my 78 II. It is the same rearend except it has drum brakes instead of disc. Mine was a direct bolt in except you'll need longer and wider U bolts. If you have the factory rear sway bar for the II, it won't fit around the hump in the back of the housing. The width of the Granada and factory II rearend are the same. The difference in braking was unbelievable. The Granada rearend also connected with the factory parking brake. I know for the Lincoln it is different and that could be something that needs fabricated.
1978 Mustang II, rearend questions 
