I have a 78 Z28, 350/turbo 350, Air gap Intake, Holy 750, Late model GM Crate motor 10:1 Comp. Mild Cam.

Will be adding bigger cam and 2.08 heads someday. Hense the large carb.

I am not sure if I want 4:11 or 4:56 gears. The car is mostly for the track.
Already have frame extenders and the roll cage is in the mail. I am keeping the interior. I want to be able to drive the car around town. Dont care in the least about gas mileage.

I dont need the car to do 90 mph but 55 mph is to slow.
The locker is stock (from a 71). Will run stock rear end till it breaks.

Anyone have any good advice and Thanks in advance

 

I would figure out how many rpm you want to turn when your going through the lights. With out that number plus tire diameter were taking shots in the dark. How many rpm is your bottom end gonna handle? What rpm does your cam start to crap out. Welcome. Post up some pics.

 

Tires are about 26" from ground to top of tire.
They are p275/65/15


The cam came in the motor, no idea what it is. Very very mild cam.

Ive never been on the track so I don't know how to answer that part.

And Thanks for the Welcome

 

I'd suggest you make a trip to the strip first, and see what it runs, and at what RPm your engine hits when you trip the lights at the end of the 1/4. You'll also want to know what gears you have now, so jack it up and either pull the cover, or turn the driveshaft and see what the ratio is.
If your engine is around 3,000 rpm's when you finish, then I'd feel comfortable going from around 3:42 to 4:11, but if you're already at 3:73 and hitting 3,000 rpm's then I'd go 4:56 gears. If your gear range is 3:08 now, then I'd go to 3:73 gears.
It all depends on RPM's and present gears.

 

Almost forgot! Welcome to Camaro forums!

 

I think it has 3.08's
I will try to hit the track in the next week or two.
Thanks for the help.
Ill figure out what the rpm's are and let you know.

I know it doesnt have 3:73, the car does 90 at 2000 rpms.

 

Write down the rpm at the finish.

Shift rpm.

Launch rpm.

2000 @ 90mph Sheez could be a 2.73.

I still would bet the 26" tire won't need a 4.56.

 

Finish - 6200 RPMs @ 90 MPH in Second Gear

Launching at about 2500
Shifting at 6000

Yes, Im running a 15.7 in second gear. Like I said these gears are way to tall.
Sorry, but I still don't know what gears are in the car.

 

Man you would be dead on if it were a powerglide. I plugged your numbers in on the Richmond site. Something isn't right. 2000 rpm @ 90 works out to 1.72. Ok so the best I can come up with is 4.11. This puts you at 6200 rpm 117 mph with a 26 in tire. If you find this isnt cool a 28" tire would act like a 4.56 with 26" tires. Now 117 mph is a solid 11.50 car. Do I think you will pick up 4 sec on gears, no. The problem now is getting to 6200rpm in 1320 ft. Does the car have a high stall converter?

 

I see you burnin down street tires in the other thread. This wont help. A quick spin to clean them is all. Street tires get greasy when hot. No dry hops either. What was you 60 foot time?