anyone have 355's w/ c-4?

[tinner]

if so how do u like it ?
3000 rpm in 3rd =??mph
what size tires do u have?


thanks in advance for your help,
tinner

[70_Nitrous_Eate]

You're gonna have to state your rear-end gear ratio before anyone will be able to give you an accurate comparison.

[Rev]

I think he wants to know about a 3.55/ 1 rear axle ratio using a C-4 auto trans. I use a 3.25/1 8" Traction-lock in my '66 coupe with a C-4. Rear tires are BFG 235/15 Radial TA's. It runs 3000 RPM at 70 MPH and that's about as much as I can stand for cruising. A 3.55/1 in my car would run (3.55/3.25 X 3000=3275) and that's a little more than I want to cruise at. If cruising is not a factor, then the 3.55 wouldn't be much of a problem just driving around town or at the strip.

Rev

[red]

With 235 60 14 tires (25.1" tire diameter), 3:55 rear end, and C-4 my speedo says 50 at 3000 rpm, it is probably closer to 60 mph.

[70_Nitrous_Eate]

Ah! I though the 355's were his tire size.

Well, with 3.73's and a FMX tranny (same ratio's as C4), I turn approx 3000RPM at 60MPH.

[Gearhead999]

I have 3.50 gears. Before I changed to an AOD I had a C-4. At 3000 rpm I was doing just over 60 mph with 225/60R15's. The rpm would drive you nuts and make you cringe if you pushed it any harder.

With the AOD it drops it about 800 rpm or so. I don't have a lock up convertor, just the O/D. Changed it to an Art Carr convertor. Really made a difference on acceleration.

[tinner]

Thanks for the help guys . I have 235/45/17's so 355's should be good for me . I had a third member built for me for $250.00 he said that was a good deal . Was it or did I get burned?

[1969Mach1]

Hey tinner did you ever lower your car? And if so any pics? I believe it was you who said you were going to lower it awhile back. Not quite sure.

[Rev]

If the 3rd member is a Traction-lock, the $250 is a great deal. I paid $650 several years ago from Currie in Ca. and that included shipping to Houston. That was for a complete unit, (I still have my old one). If you don't have limited slip, you ought to get that same guy to put it in for you.

Rev

[tinner]

rev,
It's not a Traction-lock I went cheap for now , I will need a 9" when the new motor goes in .


1969Mach1,
Yes I did lower it some it still is coming down one more inch , I do have pics I will post them when I get them back.

[gp001]

Click on this link to see a chart of exactly what to expect

http://home.earthlink.net/~gp2mff/gr/bad355.htm

[Rev]

A good 8" Traction-Lock with a C-4 , is OK up to 300 HP or a little more. Some of it depends on what the torque curve is on your engine.

Rev

[tinner]

thanks for the help guys , the gears are in and my car feels much faster.

[jim_howard_pdx]

I was roasting my tires running a non posi 3.55 gear in my rearend. Of course I am running 414 HP so there you have to factor this in too. Get into a 9" Posi as fast as you can. Run a 3.50 or 3.70 if you don't mind the revs or a 3.25 or 3.00 if you want a freeway flyer.

I went with a 2.5 gear ratio and Posi when I put in a Granada 9" rear end. I love the traction, and it is really great on the street. I have a 4.30 Posi set up for drag racing when I feel the need for speed.

With the 3.55 gears and the C4 my car was reving pretty high at 75 to 80 mpg which is where I like to be on a freeway. With the 2.5 gears I should be able to hit 165 mph.

Yes I do have good brakes, 4 wheel disks and KEVLAR pads with cross drilled rotors.