69 Z/28 Day II Project (Air Force Brat)

[big gear head]

I got the 346 gear set in my new N24. I have the 335 gears in my old M23. The 346 gear set will reduce the large RPM drop from 3rd to 4th that I have with the 335 gears.

[NorCam]

I have a set of TT wheels with some NOS H/50 Mickey Thompsons I mounted on the car to see how the 50's look on 8.50 rims. I really like the look and the width, but these were just for mockup purposes and are actually too short a profile for this car. Next up will be to mount some taller 28" rear tires but that will not happen until the car is back from the body shop.

[Ryan1969Chevelle]

Originally Posted by NorCam

Chuck, that 2.20 first gear with 3.55 gears and 28" tires will have a final ratio of around 7.80 which is going to pull the engine down when you let go the clutch. Granted your 496 is going to have more torque but there are much better transmission gear ratio combinations for street cars that will also see some highway use. (See the AGE gearing options here)

To keep it fun off the lights with 28" tall tires, I chose to run a 2.99 first gear. With the stock 3:73 rear, this should have a final ratio of 11.15 and will feel like having 5:13 gears off the light. Granted it will be a short shift when driving normally, but at WOT this should keep a good set of sticky tires running on the ragged edge until 2nd gear is pulled at 50 mph. I'd then pull 2nd gear at 4500 rpm and 3rd/4th would keep me in the 5200/5300 range on a full pass.

Best part is I get all the excitement of a great rpm launch that won't pull the motor down and will still have the final gear ratio of 3.73 for the highway runs in 4th. I may even choose to step down to a 3.55 rear gear when I rebuild the diff. That would have me in the 10.6 final range which is even more ideal. With big block torque, you could even go 3.31 and still have a better transmission ratio to easily launch the car without pulling the motor down off the line. Plus it's way more fun launching like it has 4:88's.

Might want to look into the gearing options here and check the multiplier on trans gearing x final ratio.

I vote figuring out gear ratios for these old cars!!! My drivetrain selection is very similar to yours, 2.98 first gear, 3.42 rear gears, and 26.2” tall tires. Awesome SLR (starting line ratio)

The gear spacing is extra wide and feels a little much, especially at some downshift situations.....

Ryan W31

[NorCam]

Originally Posted by big gear head

I got the 346 gear set in my new N24. I have the 335 gears in my old M23. The 346 gear set will reduce the large RPM drop from 3rd to 4th that I have with the 335 gears.

I went with the same 346 gearset Freddie. I'll need that with mine being a small block car. I bet your big block car is a lot of fun to bang gears with.

[big gear head]

I'm hoping for a better ET with the new gears. I should be able to get it on the track in about 2 weeks. Yes, it's a lot of fun.

[NorCam]

With some AMD sheet metal on its way to to repair the floors in this car, I have started pulling the body down to prepare it for a trip to the body shop in August. Starting with the firewall, I have removed the wiring harnesses, heater core, steering column, pedal carrier and the brake booster. The lower firewall and toe boards are going to need a little love and while that work is being performed, I'll be busy restoring the sub-frame, front brakes, and rebuilding the rear diff along with the original 4 leaf springs.

Today, I'm sending a set of motor mounts down to Nathan Schmidt at Sweet Ave Fabrication so he can mockup an engine block and frame for the correct Z/28 engine heights. He thinks the MT headers should be completed for September which is awesome. The rest of the Camaro parts I have on order should be along during the same time frame and that's when I'm hoping to have the car back with all the metal work completed and the floors and jambs painted up (fingers crossed). I'll follow that up by starting the assembly process and really hope to have this car finished up over the winter months. In the interim, it's almost down to the bare shell now and a good friend of mine is busy welding together a 2x2 rolling frame jig for the car to sit on. It'll support the front of the shell and the rear frame rails at the anchor points. This will make it easy to work on the car while moving it around as a roller and keeping it square.

Once the metal work is finished up with new rear quarters installed it will move onto the rotisserie where the floors and firewall with get a couple coats of satin paint before the jambs are each dressed in yellow. The inside will also be cleaned up with all of the seams sealed before it also receives a new coat of paint. Seen below are a couple shots of the rear seat frame with the X 7 factory markings intact. Normally these markings are seen in yellow, but this car was factory marked in black? Is that because the inside of the car had yellow floor paint when built so an opposing marker color was used due to the overspray? First time I have seen black markings on a seat frame?

[Salvatore]

4.56 is a great ratio with a M20 wide box. I have 28" Mickeys on the back mounted on 6" Cragar rims and have ZERO issues. No problem driving on the highway at a reasonable RPM and MPH. No substitute for gearing in a SBC.

[NorCam]

Sam,

Doesn't matter which way I turn when I leave my place...and I'm on a 70mph highway with the nearest cruise destination being 30 to 60 minutes away. In saying that...4:56 gears are not even a consideration when I can use an extra wide first gear (2.99) and a 28" rear tire. At 70 mph with 3:73 rear gears I'll be running 3400 rpm. If I swap in 3:55 gears that drops to 3250 rpm. With 4:56 gears I'd be pulling 4200 rpm at 70 mph. (so not gonna happen buddy) lol

[Salvatore]

OK Tripper, sounds like a plan. Didn't know you were going for that steep a first gear. Jody doing that Trans for you?

[NorCam]

No sir. Jeff Collins at Midwest Muncie is putting it together for me. Tough decision as they are both good builders, but Jeff had all the answers for me a second time around and earned the business.