Hey fellow sixers...I have been racing my '70 Dart Swinger (bracket) for two years...One year with the stock 1 BBL where I was running in the high 19s...Last year I converted to the Super Six setup with Clifford headers and got down to the low 18s at 75 mph with the stock 37 y/o 225". For 2007 I am building up a nice street/strip '67 225" block...It is bored .030" over and has been decked .100". I am using Ross custom forged racing pistons fit onto Clifford steel rods, a 254 cam, 390 cfm holley on a Clifford intake, high volume oil pump, electronic conversion kit, Cloyes double roller chain, a mildly prepped head and I'm shooting for 9:1 CR. The stock 904 will be rebuilt with a Transgo TF2 shift kit. With the Super Six I was launching at about 1700 RPM...With the new setup I will probably retain the 1700 RPM launching point mainly because the stock drum brakes cannot hold much more than that, and I figure the 1700 is relatively safe on parts. I believe the 7 1/4" is plenty adequate, but some friends think otherwise...Does anybody have any advice?

Thanks!

Check the gear oil level, and run it until it breaks. In the meantime, keep your eyes open for a replacement/upgrade.

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"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO

That 7 1/4 CAN be ok. What gear ratio? is it a sure grip? do you run slicks?
I was running a 3.91 SG 7 1/4 with slicks in a mid 13 sec car. It did not break, but I replaced it with a 8 3/4 befor it did. That was asking a bit much from a 7 1/4.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

With a 7 1//4, it is not a question of if but more a question of when it will break.
The addition of a sure grip unit makes a 7 1/4 a lot stronger.
The hard shock of a manual shift, aggressive AT shift kit or wheel hop will cause trouble. Spider gear failure is what usually kills the unit. Shimming ths spider gears tight helps but there is not much else you can do with a gear that small, it is simply the "weak link" of the assembly.
DD

I have a 7.25 in the Valaint and live with the fact that Im one burnout away from failure. The thing has been whining for years......it becomes a question of how long one tortures oneself with impending failure.....

Yeah I know, its time for an 8.8 Explorer .........but the 7.25 just keeps limping along.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

No I have'nt been using slicks and I do not intend to if I can get by with no tire spin...No burnouts either. I believe the gears to be 3.55 but I am not certain. Oh and by the way...I don't manually shift the car...I put it in Drive and let the 904 do the work. Plus, the shift kit won't add too much to the equation either.

Should I start saving some money for a 8 3/4"?

You will have to save a lot.
I would consider an 8 in Ford, from an early Mustang, Falcon, Comet, V-8. I just got one drum to drum from a salvage yard for $100. 8 3/4 "A" body rears are going for about $500.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

YES! By all means find something stronger than that 7-1/4 if only as a spare. Like someone else in this thread said, "not if but when".
the one in my 90 Dakota went to smithereens soon after I sold it to my brother in law! (and that was a measly 3.9!) My mother who drives like a typical old woman readily blew the one in her old 5th avenue (and that was 100% without my help, but I had the job of replacing it with an 8-1/4)
I had 3, not yet blown up ones between my garage and shed, all F body ones, and I wound up scrapping 1 and giving away 2 (all were 2.76 peg leggers) cuz no one wanted them!

[quote="sandy in BC"]
Yeah I know, its time for an 8.8 Explorer quote]


Explorer, As In Ford? Or Is This An Aftermarket Name Brand?

Ford Explorer....8.8 comes with disc brakes 3.73 gears and Trac-Loc....

Spaldings in Spokane $350

It has to have one side narrowed.

Search Ford 8.8 and heckshemi

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Ford. Some Explorer rears are pretty close to the right width. They're also strong enough, and have good aftermarket support (gears, limited slips, etc.). They have the 4.5" bolt pattern. There are some with disk brakes, too.

_________________
"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO

You could run "cheap street".....
How would a "Lincoln Locked" 7 1/4 hold up????
I might try that. hehe...
BBBanjo

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225 Cubic Inches of Iron-Head American Muscle

225 bored .040 /.100 off block, Schneider Cam 224@.050~ .480 lift - Stock valves, blended bowls, Offenhauser intake with 500 Edelbrock carb

I plan on sticking with the 7 1/4 for now and looking for an 8 3/4 in the meantime. I would have thought the 7 1/4 would have been toast by now since I have made at least 500 passes the last two seasons...And half of those were with the Carter 2 BBL and Clifford Headers running low 18's. I bet I will get one season out of the 7 1/4" before I replace it...It sucks replacing parts during racing season. Maybe I should just put a DANA 60 in it and be done with it lol

Put a 8 3/4 in it and be "done". ( or any of the other larger units suggested above)

Over the years... I have welded-up the spider to side gears on a couple of 7 1/4s, they both blew-up in short order.
One broke the R & P gears, the other split the ring gear carrier clean in half.
DD