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Discussion Starter · #1 ·
Hey guys, my name is Finn and I just picked up a 1966 Impala convertible, 283 with a powerglide. It has 54,000 original miles but has work to be done. I've worked on vehicles for years, but mainly Imports and motorcycles. I have a few basic questions that might seam dumb, but I'm new to the chevy small block, so bear with me.
How do I tell what rear I have without pulling it out?
Spline?
C clip?
Diameter?
Gear Ratio?
I'm told the 283 isn't worth building, but all I wanna do is street drive it and I do LOVE standing burnouts, would I be able to do what I want with a shift kit, a 2500 stall TC, and a minispool?
The 283 has a decent cam, longtube headers, and electric pump and a edelbrock 625 cfm carb.

Sry for the novel, thanks for reading
 

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How do I tell what rear I have without pulling it out?
Count the number of bolts on the cover, 10 or 12.

Spline?
Not sure, sorry but I think 12 bolt is 30 and 10 bolt is 25.

C clip?
Yes, it's a C clip style rear.

Diameter?
A 10 bolt cover is 8.25", a 12 bolt cover is 8.875"

Gear Ratio?
Look for the code on the passenger side axle tube, front or top of the tube, usually stamped closer to the center section than the outer end, then google the code you find, likely a 2 letter code.


I'm told the 283 isn't worth building, but all I wanna do is street drive it and I do LOVE standing burnouts, would I be able to do what I want with a shift kit, a 2500 stall TC, and a minispool?
You don't want a spool on the street with stock axles or you'll break something! A 283 in an Impala will struggle to do burnouts.
 

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Welcome Finn!
IMHO the 283 is a good little motor. Your Powerglide is a dog though. Swap out the 2 speed auto for a 3 speed or better yet 4 speed/OD auto trans and you'll see a real difference. Then if the 283 doesn't do what you want, you can heed all the advise that will follow mine (go bigger, more displacement for these heavy cars, etc.). Either way you will want a different trans to spin the tires, regardless what engine you have in front of it. With the 2 speed the only way to break em loose is stomping on it around a corner or on wet pavement.
 

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Welcome Finian, Must be nice in Paradise. What state is it in? I went to Hawaii once. These guys all give good advice.
 

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Discussion Starter · #5 ·
Unfortunately that's all I keep hearing, I do have a 350 sb and a turbo 350, but the motor needs bored and I'll have to change my column to run the 3 speed... Just a bit disappointing.

Also Paradise is in Lancaster, Pennsylvania. No joke, I always forget that it's sounds like sarcasm when I put that as my location, lol
 

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Discussion Starter · #6 ·
Thanks for the info, from what I've been finding there is a 27, 30 and 33 spline, and 8.75 and 8.80 all in the bolt option.... Sorta confusing
 

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I have family in Lancaster, Pennsylvania.
Dont really have to change the column as the aftermarket makes parts for the conversion.
 

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Welcome to the Team Finian!

The 10 bolt Spicer rear end has 28 spline axles and an 8.2 inch ring gear.

The 12 bolt Spicer rear end is very similar to the Dana 44 (it was based on this rear originally) and has a 30 spline axles with an 8.875 inch diameter ring gear.

As to the rear gear ratio you can pull the cover and count the teeth, or attempt to elevate the rear end and rotate the wheel once and count the number of times the drive shaft turns (the most frequently encountered rear gear ratio will be a 3.07 or a 2.56 if the person wanted the maximum fuel economy). The proverbial 4/10 will be either a 4.10 or a 4.11 gear ratio (both were offered and the only way to distinguish between them is to pull the cover and count teeth) as you will not be able to count the difference in the drive shaft rotations. Other gears were a 2.73, 3.21, 3.55, or a 3.73, 3.90, and possibly a 4.56 or 4.88 if you have a 12 bolt rear.

With a 4.56 a 283 should be able to spin the tires on dry pavement with a three or four speed automatic, but not the PowerGlide as that is a TH350 with a busted first gear that takes off in second gear all the time, instead of first gear.

A higher stall speed won't help, a mini spool means your motor has to produce twice the effort to spin both tires at once (a real challenge for a 283), and the shift kit won't have any affect on tire spin either. What it takes to over come the static friction of the rear tire is torque.

This is a good time to explain the difference. Torque applied over time equals horsepower (a calculated number that expresses force applied over time). So though your little 283 doesn't offer much in torque due to it's small bore and short stroke it will rev to the moon when built with the right parts. This means that you get to add together a whole bunch of little power strokes in one minute with a motor that is spinning at 10,000 RPM. to get a bag full of horsepower which if dumped with a clutch into a four speed gear box would be able to spin the drive shaft around fast enough with the right gear to pull the front tires off the ground if you could hook that power to the ground.

Problem is that sudden application of clutch slowes the motor down such that the car drops back down to crawl the rest of the way down the track. With a 496 big bore big stroke production big block you would still be sitting at the starting line the difference is the tires are smoking as you fight for traction. The Goldilocks solution is a Small Block Chevy around 383in displacement.

This gets you more torque to accelerate the car or to spin the tire if that is what you want, and not so much that you can not stop the tires from spinning as you would experience with a huge big block. They make the big block to displace upwards to 730 inches or so using a aftermarket block (same bore centers), and over 900 cubic inches in size it you don't mind not using any recognizable BBC parts at all (which begs the question why even call it a Chevy?).

Big Dave
 

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Discussion Starter · #9 ·
Awesome! Thanks for all the help, I was waiting for the infamous Big Dave!
I have another be guy question, what manual trans could I run? Least price and modification. I understand I have to cut my trans tunnel, put a pedal assembly in and change trans mount, I've done tons of those,

Thanks
 

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Muncie is the most cost effective. If you can find a Borg warner T-10 that still shifts smoothly that is the period correct four speed for a 1957-'64 Chevy. The Muncie was the four speed that Chevy used from 1965-'72 and then went back to the Borg-Warner Super T-10 in 1973

Big Dave
 
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