7 1/4 behind 340
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Longgone
John/68 Barracuda & Dart
Sure, just drive it like an 80 year old. :toothy10:
yellow68runner
Banned
It's just a matter of :clock: !!!!!!!
goldduster318
Overzealous Car Modifier
it will work for a block or two
OldVart
Well-Known Member
I blew one to pieces behind a 318 years ago. I replaced it with another 7.25" I had laying around, and ran it behind the 318 for a couple of years, then about 16 years behind a hot 360. I pulled it out when I started the rebuild on the Valiant and I have an 8.75" to replace it. The biggest thing I found was to come off the line under steady throttle, and to not spin the tires around a corner. If you punch it hard off the line, or romp on it around a cormer, it WILL self destruct. Run it till it blows up, but start saving your pennies for either an 8.25" or 8.75".
stroked 340
Banned
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Theres a reason ma mopar put 8 3/4's behind 340s!!!!!!!
65barracudadude
Well-Known Member
It will break!!!! Just a matter of when. Thats why I dont have a V8 in my car yet. Dont have the rear to handle it.
Longgone
John/68 Barracuda & Dart
You nailed it stroked340! A good way to tell what parts work well together is to look at what Chrysler grouped together. This goes for many things, such as torsion bars ,brake drums, radiator capacity, etc., not just differentials.
Confusedcuda
Well-Known Member
I just went through this. Had my car painted last summer, went from a 273 that had headers, hyd. cam, 4 bbl. ign. etc, pretty much everything you could just about do to a 273. I would guess it had around 210 HP or so. Ran like a dream with my 7 1/4 with 3.55 gears non-sure. I wanted to do at least one car show with it, had plans to upgrade to 8 3/4, but was dying to run it. I had a lot of people tell me that the 7 1/4 would handle 250 to 300 HP. So I put my 340 that is darn near stock 9:3:1 comp. or so, headers, 650 eddie carb,etc.all from my 273(except the carb) I did not go crazy, but did do a couple of straight burn outs amongst other things, and on the way home CLANG!! every so often. Opened it up, 11 teeth missing on the pass. side spider gear. It is a damn shame that these can't be built to with stand more. My was so light, I was able to chuck in the dumpster at work drums and all, all by my self. Now I have a 8 3/4 with 3.55 and it still runs great, but it is probably 100 lbs. heavier....This was just about 3 1/2 months ago..
65barracudadude
Well-Known Member
Ya, I've hammard 3 of the 7 1/4's in my day. All of them with stock 318's and 1 273. They just can not handle abuse.
autopar3000
Well-Known Member
Pretty simple... don't hit it hard and you'll be fine. Hit it hard and you'll break it.
dgc333
Well-Known Member
Yes, the suregrip 7.25 is much stronger than an open 7.25. If you drive it knowing you can't be beating on it, it will last just fine. 318 A-bodies lasted for several 100,000 miles with 7.25's when not beaten on.
2 Darts
A-body Addicted
A lot of the '66 273 4bbl cars had 7¼s and automatics. Mine had over 300K when I sold it. From what I could tell, the fluid in it did not look too bad.
edbux
Well-Known Member
It will work. Just put a switch under your gas pedal that will activate a bomb in the likely event you floor it. This way, the rear end exploding won't be noticed.
This was what a trans shop told me when I took my 72 Dart (in 1976) with a 318/904 that was missing Drive 2. Of course, I changed drive 2 to rear end. I got the message and put in a 727.
This was what a trans shop told me when I took my 72 Dart (in 1976) with a 318/904 that was missing Drive 2. Of course, I changed drive 2 to rear end. I got the message and put in a 727.
On of them members has a sure grip 7 1/4 behind a 360 and it is doing ok. They fixed a lot of the problems with the sure grip model and they can take a lot more then a non sure grip 7 1/4. Just don't throw a set of slicks on her and you should be ok.
73golddusterkid
Gold Duster Kid
Like everyone else has stated you had better not beat on it. I just blew my 7 1/4 with my duster, and it only has a mildly built 318. Being young and dumb i couldn't keep my foot out of the loud pedal!
Mick Semantel
Well-Known Member
I'm running a fresh (with in the past 2 years) 360 with a cam, headers, and carb with a stock 7 1/4. Just listen to what people have to say, keep it cool off the line. I'm waiting for mine to go out so I can put the 8 1/4 in that I have in the garage.
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