Im trying to figure out what my gear ratios for my 91 B4C are. From what i have heard the b4c's ahd a different 5th gear ratio. I have a recipt for what my 5th was replaced with and i was wondering if there is a way to find out if it is acutllay the rigth gear.

The part description is "c/s 5th 55t V8 camaro". item number is listed as 13.65. I looked this up online and came up with a website that claims this item description for an 84 T5 5th gear. There are 3 different 5th ratios for 84 tho. Anyone have any insight into what the actual ratio is suposed to be, and what this ratio is?
I'm plagued by the high reading tach problem so i cant actualy check my ratio right now.
I'm workin on it for now tho.

 

There are not different ratios for those. I don't know where you heard that; but it's pretty fanciful.

They're the same as the other TPI & L69 T-5s. 2.95 first, .73 5th.

AFAIK the half of 5th gear that goes on the mainshaft was the same from 83 up through 92. It wasn't changed in the re-design of the T-5 in the mid 80s (made it into these cars in 88, some other brands a year or 3 earlier). So the 84 5th gear should fit them all up to 92. For that matter, if you changed the one that goes on the end of the countergear, you could put the better ratio in a LG4/L03 T-5.

So, the 5th gear ratios are, .73 for the high-perf cars, 83-92; .63 for LG4/L03, also 83-92; and some other # for the 6-cylinder cars. I have not so much as the vaguest clue what those got, since I've never touched one except by mistake.

 

https://www.thirdgen.org/calculations according to this there are many different t-5 combinations availible through out the years that changed between the motors. I'm just gonna throw an after market tach on it for now figure it out the deffinate way. I'm guessing its a .73 or .74 by those charts. A .63 is what i wish i had tho. Get some free mpgs

Ty for the help.

 

The gas mileage difference is negligible; 1 mpg at best.

I screwed up and forgot to look once, and put one of those .63 5th gears in my car. I absolutely hated it. I pulled the transmission back out after just a couple of weeks and changed the 5th out of a better transmission into it. I made a point of never making that mistake again.

The problem was the typical low-perf gearing problem. The ratios were too wide between 4th and 5th, so it always seemed like I needed another gear in between. 5th would hardly go up a long hill without slowing down, but it was a BIG jump to 4th.

I have a T-56 now; about the same (.73) 5th as a high-perf T-5, plus a .50 6th. Decent enough spread of ratios. I only use 6th starting at 65 mph. But I don't have enough gear, all I've got is the stock gears (3.73); maybe someday I'll put a 4.10 or something in it. I'm not in a real big hurry at the moment.

I can't vouch for the accuracy of people's web pages. All that I know about the ratios, I found out by looking at transmission parts, and lots of them, not web pages.

 

i hear that SFK> best to get it striaght form the horses mouth. Does a t-56 fit straight into these cars? That transmission is my all time favorite. You would make my day if you said it could be done without cutting stuff up.

 

Yes the T-56 fits; but it's not quite a direct bolt-in. Since you have a T-5 car the only thing you have to "cut" is to lengthen the shifter hole rearwards by about an inch. So little actually, that the stock rubber boot still fits; although it does lose a couple of its screw holes. So that part is pretty minimal.

You need the T-56 itself obviously. The one to get is the 94-97 Camaro/Firebird (LT1) version. The 98-up (LS1) ones are different, and yet another few steps farther from a direct bolt-in; and the 93 one has gear ratios that are too wide. 94-97 are the ones.

When you get your transmission, get the flywheel and clutch if possible. They are totally different from T-5 stuff. You'll need the right hydraulics, a T-56 shifter, and a different crossmember. Your stock torque arm will work if you get the T-56 torque arm bracket; but it makes more sense to get a replacement crossmember/torque arm such as the Spohn one.

You'll need to do something about the speedo; I believe in your car, you can use one of the digital pulse rate converter boxes like a Dakota Digital, and the stock T-56 VSS.

I'm extremely happy with mine.