What about 3.55 Gears
 

Posted this in another topic but thought I might try here as well. Have a 69 restomod. engine is 302 dynos at approx 320 HP. Currently running a 3.00 third member and 275/40/17 rear tires. thinking about putting in a 3.55 positraction. Too much for a street machine? Anyone that has done this swap I would appreciate their comments.

I don't think it is too much. I've got a 69 Mach 1 with 3.55s and it's not that bad. I had a t-10 in it and as we speak I am having a t-5 put in it so I think it should be really nice when it gets done. I guess it all depends on what trans. you have.

I have a 302/C4 and 3.55's in my '65, it is a great combo. If I had overdrive I would go 4.11 for sure. 3.55's are definitely streetable. With your tire/engine combo I would think you could go 3.73 if you want to get aggressive. If you log lots of highway miles, stick with the 3.55's. Going from a 2.80 peg leg to a 3.55 posi (traction lock for the Ford purists) was the best upgrade I have made so far.

Have fun,

-JON

The guy that built my engine said when asked his advice some yrs. ago, that when I got my 3.25 Traction-lock (upgraded from 280 open), "I would think I had gained another cylinder". He was right. 3.25-3.55 seems about right to me.

Rev

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'66 Coupe, 306, 300 HP, C-4, 13.97 e.t., 100.3 mph
1/4 mi.

I also have 3.55's with a C-4 in my 67. I switched from 2.79 to 3.55 when I had a 289 in my car and it improved my 1/8th mile et by half a second. They are great for driving on regular streets, but it revs a little high on the freeway (not too bad unless I am driving far) I would not go farther than 3.55 without an overdrive though.

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67 Fastback - Arctic White Pearl paint
351W 415 hp, Trick Flow Alum. Heads, C-4 Trans, 3.55 gears, Front Disc Brakes, 1-1/8" Fr. 3/4" rear sway bars.

well i have 4.30s in mine but it really sucks on the freeway i can only about 55mph and get like 4mpg. So i wouldn't go much higher than 3.55 unless u want to scarfice what i have. But for the street the 4.30s are awesome.

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69 428 cobra jet: tons of mods.
97 f-150 mark III

I run 3.50 in my 68. Has 289 with AOD. They work real well and with the O/D really cut the RPM down on the highway. Thinking about going to 4.10 though?