After 2 long highway trips in the last 2 weeks, it's just not as much fun on the open road as it could be. Running an indicated 70 @ 3000 rpm with the top down wind roaring and the flowmasters droaning, it's just too much. Crank the stereo loud enuf to hear it and I'm deaf for an hour after I get out of the car. Forget about trying to use the phone, not possible..

I've never checked my gear ratio or looked for numbers / codes, always ***-umed it was a 3.08 or so. It is a 10 bolt pegleg, and other than 37 years and who knows how many owners, I have no reason the believe it's not original. The engine (L30) is, and the powerglide was until I put the muncie in.

I timed my speedo by highway mile markers @ 60 mph, got 58 seconds or so.
Tires are 25.5" in diameter.
rpm @ 70 is 3000

Calc at classicchevy5speeds say gear is 3.42. Is it really?

Hope I make some good $$$ this fall. I wanna 383... and a tko 600... and a quieter exhaust.

Is it?

Couldn't you just get us the axle code? Would be easier to just look it up in my book.

Couldn't you just get us the axle code? Would be easier to just look it up in my book.

it's late... I'll jack her up and crawl under in the AM, k?

It's not a 3.08, 3.08's are 2600 at 65. but are you sure your speedo is correct???

It sounds like you have the 3.42's (or something very close to that).
The math behind the calculator is correct.
A TKO600 with 3.55's or 3.73's is the hot ticket (I think). With that said, my Corvette had a TKO600 with 3.36 gears and that worked nicely as well.

My set up of 3:73 with TKO 500 with 3:27 first gear works with 302's but Tko 600 works better on motors with bigger punch. I do 70 @ 2350 with same tires.

It's not a 3.08, 3.08's are 2600 at 65. but are you sure your speedo is correct???

haha... I think I'll try to get an axle code this morning, although after all these years who's to say the same gears are in it.

I'm not certain the speedo is correct. I'm not even completely certain my new tictoc tach is correct, it bounces around some under acceleration, but the needle is stable cruising.

The speedo gear was picked 5 years ago, by a member known for accuracy to the point of anal-ness (lol) I did do a timed measured mile @ 60 as accurately as I could, it's kinda scary doing 60 on the tollway here, good way to become a hood ornament on a Kenworth! I generally drive my truck at 78, and am slightly over the average speed of most of the traffic. At an indicated 70 in the vert, everyone was passing me, but that lil 327 is buzzing hard.

haha... I think I'll try to get an axle code this morning, although after all these years who's to say the same gears are in it.



Just let us know. I'm sitting at work staring at a computer screen all day with not much to do so I can run out to my truck and get my book. (don't ask why I have it in the truck). Generally......rear gears are one of the last things changed out so the chances of the rear gears being original are fairly good. Of course there's only 1 or 2 ways to find out :p

Axle Code is: PA 11170
car is early march '68

The spin a wheel and count driveshaft turns test shows exactly 1.5 turns! (open rear, one wheel still on the ground.)
That works to 3.08... darn thing sure does buzz at 70 tho, while every other car and truck on the road is zooming by me like I'm parked. Tac reading incorrect?

PA isn't in the book for a 68 Camaro, might be PE which is a 3.08:1 Posi, or one of any others. There is a PA in 68 for a Chevy II with 3.08:1 non-posi

11 = Month: November
17 = Day: 17th Day
0 is probably G which = Assembly Plant: Detroit Gear and Axle

NM, you said it wasn't posi, check the code again and make sure it's PA.

Let me type this out from my book. At least I can just cut and paste it next time :D

1968 Camaro Rear Axle Codes

BA 2.56:1 (small ring gear)
BB Posi 2.56:1 (small ring gear)
BC 3.36:1
BI 2.73:1
BL 3.07:1
BM 3.31:1
BN 3.55:1
BO 3.73:1
BP 2.73:1
BQ Posi 2.73:1 (large ring gear)
BR Posi 3.07:1
BS Posi 3.31:1
BT Posi 3.55:1
BU Posi 3.73:1
BV Posi 4.10:1
BW Posi 4.56:1
BX Posi 4.88:1
BY Posi 2.73:1 (large ring gear)
BZ 2.73:1
PB 3.31:1
PE Posi 3.08:1
PG Posi 3.07:1
PH Posi 3.55:1 (small ring gear)
PK 3.55:1
PN 2.56:1 (large ring gear)
PP 3.07:1
PR Posi 3.31:1
PX Posi 2.73:1 (small ring gear)
PY 2.56:1
PZ Posi 2.56:1
Q2 3.55:1 (large ring gear)
Q3 Posi 3.55:1 (large ring gear)

- 1965-1969 Chevrolet by the numbers - by Alan L. Colvin

PA is listed in the 1967 Camaro Rear Axle Code list:

PA 3.08:1

And in both, the 1969 Camaro and Chevy II list:

PA 3.08:1

Perhaps you have an earlier axle or it's been changed out. The date from the code being November doesn't really line up with a March 68 car.

Either way, if it's PA, the book lists the PA (3.08) as being used for the 67 Camaro, 68 Chevy II, 69 Camaro and Chevy II. And you calculated it out to 3.08 which matches up so perhaps they used the PA in 68 Camaros as well and the book is missing that code for the 68 Camaro.

ok, here's the code:
http://home.comcast.net/~Jimragtop/axle-code.jpg
I'm currently reading that as: PA 1117G I double checked the build date on the cowl tag, it's 03C, so that's late March. It is a pegleg monoleaf perch 10 bolt rear.
So, I guess it is NOT the original axle, right? But it is a 3.08.
So... my tac is off. My perception of excessive buzzing on the highway may be off a bit too. I'll go to radio shack after completing the day's hunny-do's and yard work, see if I can't rig some kind af tach filter and get that under control. The next time I'm on the highway, I'll run another measured mile, or maybe flag down a local cop and get a radar shot to verify my speedo. Either way, those flow 40's gotta go, and I'm putting a TKO600 on my wishlist. In the meantime, no more long highway runs!

I won't be the one to say it's not the original axle because I haven't been in this area of research long enough. For all I know, 4 months might not be too long between axle dates and build dates. The axle code on my 67 though is only like 1 week from my car's build date. Also, as I stated earlier, according to THIS book, the PA was used on 67 and 69 Camaros as well as 68 and 69 Chevy IIs, so perhaps there is an error in the book.

As far as the tach is concerned, I think what I would do is run down to the parts store and buy a cheap tach ($30-$50) and plug it in to see how it reads at the same speeds. I'm sure someone else here may know the "correct" way to test a tach, but sometimes I just do what I know how to do, and a tach is very easy to hook up.

My 67 doesn't even have an engine and trans at the moment, not just not in it, but they don't exist at the moment. I am definately looking at putting a 5 speed, most likely the TKO500 in, and I'm edging every day further away from loud mufflers myself.

I would love to sell you my TK0 500 with custom shifter but I dont think thats what you want as its got a 3:27 first gear with 0:64 od...I got this tremac because of the 302 and I am wanting to go stroker motor but with a 3:27 first gear and 3:73 rear make a 12:19 start line ratio and thats not most desirable unless you are running 31 or 32 " tall tires. I would consider it if you are still interested,, Trans has about 800 miles on it. Its about a year old.. I think you will be happier with a tko 600 with 2:87 first gear, Do the math , with your 3:08 gear , the 3:27 first gear will make your start line ratio 10:1 and that should be desirable and make your cruise gear 2:88. Do the math again and see where your cruise rpm will be.

let's talk, although I ai't too sure when the A:wife will let me, and B: funds will permit and c: how my projects wills get prioritized.

When I "thought" I might have a 3.42 gear... I was thinking tko600 would be perfect, with a 3.08 (and some odd tach behavior) the 500 I think would be a better choice (10.07 1st), even if I stroke it. From the amount of blowby I'm getting these days, going thru the motor this winter is inching ahead of disk brakes (sigh...) and if the motor and trans come out.... well, anyone wanna buy a nice M20, 2 seasons on a rebuild, shifts sweet, comp plus included...lol.

Just finished washing a QUART of oil outa the engine bay, result of 3 hours @ 70 mph... really wish I'd at least reringed this thing when it was on the stand a few months ago.... maybe if I drill a hole in the pcv valve it will "recylce" a lil more of this!

Well if Jim doesn't end up being interested in the TKO 500 let me know, as I'm going to be looking for one for my 67 when it's time. My car has 3.31:1 gears so it should do just fine. Let me know what you two decide to do.

Jim, it's time to pull that little mouse out and drop in the 383 you're having dreams about :) The 383 is what I'm looking at for mine as well. Should be a fun build.

I would love to sell you my TK0 500 with custom shifter but I dont think thats what you want as its got a 3:27 first gear with 0:64 od...I got this tremac because of the 302 and I am wanting to go stroker motor but with a 3:27 first gear and 3:73 rear make a 12:19 start line ratio and thats not most desirable unless you are running 31 or 32 " tall tires. I would consider it if you are still interested,, Trans has about 800 miles on it. Its about a year old.. I think you will be happier with a tko 600 with 2:87 first gear, Do the math , with your 3:08 gear , the 3:27 first gear will make your start line ratio 10:1 and that should be desirable and make your cruise gear 2:88. Do the math again and see where your cruise rpm will be.
I have a 67 big block,454, 12 bolt currently with 4:11 changing to 3:55.How would your trans work with this setup?How hard was it changing the pilot bushing?I'm interested in your trans.Thanks

I have a 67 big block,454, 12 bolt currently with 4:11 changing to 3:55.How would your trans work with this setup?How hard was it changing the pilot bushing?I'm interested in your trans.Thanks

They make a pilot bushing puller.

The PA code was also used in 68 Camaros, it's a 3.08 10 bolt non posi axle. It's referenced in the P&A 30 parts manual, MPC721 parts amnual, and 68 Serbice bulletin 68-I-1.

Thanks Mark, was hoping to here from you on this. Wonder why my brand new oer tictoc is indicating 3000 rpm @ 70 mph? Just can't be right w/ 1:1 high gear & 25.5" tire. Think I needa find a friendly cop to shoot me on radar @ 60, but judging the number of cars passing me @ indicated 70, the speedo couldn't be that far off!