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I converted the ‘67 big block hood on my ‘64 convertible into a functional L88 style hood and I love it. This one will stay a stock 65/66 big block, but I am having the intake grills powder coated matte black. I drop them and the front grill and bumpers/brackets off Saturday.
In other news, I love it when a plan comes together!
The new hood almost a perfect fit! Even up here around the nose is almost perfect. It is also nice and flat. Minimum prep will be required. I think it’s going to look damn good! Oh and this bad boy popped right out with a little alternating crow bar action and balanced perfectly on the jack. I simply rolled it out. Notice anything interesting about this stock 1964 diff?
Hi Mark - Car is looking great as it starts to take shape - pic attached is what I was referring to at post #200 and Saddletan referred to at post #211 - showing the hood cowl extension for cold air induction drawn from the base of the windscreen - Best Regards GV
In other news, I love it when a plan comes together!
The new hood almost a perfect fit! Even up here around the nose is almost perfect. It is also nice and flat. Minimum prep will be required. I think it’s going to look damn good! Oh and this bad boy popped right out with a little alternating crow bar action and balanced perfectly on the jack. I simply rolled it out. Notice anything interesting about this stock 1964 diff?
Looks like 3899148 casting number on the diff case. Is that a 64 diff. I was thinking that casting number was used in later years?
It is indeed a 3.31 posi! I’m surprised, but this car was a rare one originally. It was built in May of 1964 and is an AO Smith body. Do you think it came with that posi or was it updated later? Notice the snubber has the reinforcements welded on. Perhaps in response to the service bulletin or added later when the diff was replaced. Something interesting, I’m almost positive the crossmember and sombrero bushings were original and never removed.
Originally black with a black and silver interior (I recently noticed that the only remaining silver is the welting along the edge of the doors by the kick panel). Everything else is tired and worn out black with a white exterior. Originally a 365hp 327, now some non-descript 350 that sounds like a truck.it also has power windows that actually work and the off-road exhaust that I just hacked up as it was rusted through in several places. Yesterday, I was working on the rear and I noticed fluid dripping on the wife’s yoga mat upfront. Seems the vibration of knocking out trailing arm bolts caused the expansion tank hose to crack in half, fall off, and spew coolant everywhere. This after the idler arm bushing disintegrated when I knocked it loose from the relay arm and one front brake line cracked at the junction when I unscrewed it at the wheel.
Just a few of the many things neglected over the years that cause me to be happy I’m fixing BEFORE I drive it again!
Mark - the ident numbers are sometimes on the flat spot on the bottom of the diff between the spring bolts and the rear diff cover - GV
PS: is that a date clock in the pic ?
C2 & C3 Corvettes built from 1963 - 1981 used a non standard 10-bolt design. because of an independent rear suspension with transverse leaf springs and the specialised axle housing is not easily upgraded to accept a 12 bolt carrier which requires custom axles. - GV
Originally Posted by Factoid
That’s what I’m wondering, JV, it sure seemed like it has never been out of the car and I dropped it out of the ‘64 coupe yesterday.
Last edited by roadster65; 01-18-2019 at 08:54 PM.
Reason: spelling
That is a date clock, GV. I’ll get the stamping in the morning.
Hi Mark - The engineering "trick" with a transverse rear spring axle arrangement is to get the geometry correct. There is a need to reduce the stress on the outside wheel in a corner. Duntov, Drieger, and Zetye carried out the engineering solution for this system. One of the ways they attained that precise control without the usual harshness was by using rubber bushings at the eight mounting locations. Even the differential itself was mounted in rubber, with the front mount carefully designed to provide cushioning in both rebound and jounce. This is also the reason that you should replace ALL these bushings.
Differential Castings - Over time and through wear and tear, most of the markings have long ago eroded away. There seems to have been three different carriers used from 1963 - 1967. The carrier for the 1963 car was listed under part number 3822962. In may 1966 the number changed to 3876475. Then in the 1967 parts book, the number changes to 3917861. Chevrolet did not change parts numbers lightly. They only changed numbers when there was a change in design.
Casting Number(s) - There were three different casting numbers used. The first was 3818753-N. The second was 3876476-N and the final was 8899148-N. (your number in pics) The significant point here is that every time the casting number changed, the part number also changed.
Casting Date - The usual casting date code was used here. The first letter stood for the month, the second, and possibly third, stood for the day of the month, and the final two numbers stood for the year.
Assembly Date - This number doesn't actually exist on the differential, but instead, the date that the differential was cast. the casting date on the differential should precede the assembly date by one or two months.
Factory Location - The plant designation was stamped immediately following the production date. There were three plant codes : B : Buffalo - G : Gear & Axle - W : Warren. All of the 1963 - 1967 differentials were created at the Warren, Michigan, plant.
Differential Covers & Plugs - There are some major differences in the differential covers that fit the 1963 - 1967 Corvette. There was a significant problem with these covers being the tendency to break their mounting ears off. There are two different examples,, the early part number was 3830303, then in March 1966 was changed to 3871375.
1963 - 1964 Rear Axle Ratio's
Code : CA - Ratio : 3.36:1 - Type : Standard
Code : CJ - Ratio : 3.08:1 - Type : Positraction
Code : CB - Ratio : 3.36:1 - Type : Positraction
Code : CC - Ratio : 3.55:1 - Type : Positraction
Code : CD - Ratio : 3.70:1 - Type : Positraction
Code : CE - Ratio : 4.11:1 - Type : Positraction
Code : CF - Ratio : 4.56:1 - Type : Positraction
Code : CZ - Ratio : 3.08:1 - Type : Standard
Code : CX - Ratio : 3.70:1 - Type : Standard
The reason for this change was a change to the threads in the oil filter plug. The change was from a coarse thread of 20 threads per inch for the early cover to a fine thread of 13 threads per inch for the later design. In 1963 & 1964 a metal Positraction differential tag is added to the filler plug. In 1966 the tag was made out of red plastic.
Driveshafts - The driveshafts were all unpainted, These shafts were made of extruded steel and were welded to the forged steel yokes that hold the universal joints. The outboard end of the driveshaft is bolted to the rear spindle with black phosphate bolts. These bolts are held in place with a peculiar device called a "French Lock". These are metal U-Shaped devices hat allow for the ends to be bent up in an effort to prevent the bolts from turning. In 1965 the shafts were shot-peened for the big block cars, also the differential yoke is secured to the output yoke with a steel cap. The small blocks used a steel u-bolt for the same purpose. With the French Locks note which way they are installed by taking a picture.
Without the aid of descriptive details, numbers, and pictures I hope these comments help you identify what type of diff you have
Best Regards GV (Eagle Typist - Hover & Swoop)
PS: Some interesting side pipe, rear spoiler, and fender vent treatment on this car - some ideas for contemplation
Ordered these rear spindles a week ago and they showed up yesterday along with the Wilwood big brakes for the rear. Still don’t have the Wilwood fronts that I ordered from Summit before Christmas. Here you see the original and the new:
I’ve spent the last couple of days doing clean work. Assembling trailing arms, building the Track 1 rear components, etc. Dirty work will commence this week as I would like to clean and paint the back half of the chassis in preparation for installing the fantastic Ridetech rear suspension components. I have all the parts to finish the rear, just have to get to it.
My chassis plan has always been to proceed in three phases:
Degrease, clean and paint the front portion of the chassis where the front suspension and steering components mount and install the new components.
Degrease, clean and paint the rear portion of the chassis where the rear suspension components mount and install the new components.
Replace the engine and tranny. Degrease, clean and paint the mid chassis and portions of the engine bay while the engine is out.
I’ve made some discoveries along the way (crushed brake lines, rusty fuel line, rotten rubber hoses, etc.) as you will. By the end of February, I plan on completing this work and getting back to the body work as the weather warms up here in south Texas. I’ll post some pictures of the beautiful Ridetech engineering later today.
Three things impress me about the Ridetech components.
The quality, fit and finish of their products (ok, that’s three right there, but I’m lumping them together).
The engineering, design and knowing when to partner with other experts (clearly I’m not good at this!)
The willingness to help, follow up and lightening shipping speed (a clear fail as that’s now nine)
So nine things (see above).
i assembled the rear housing, crossmember and mounts. For the housing and pumpkin, Ridetech turned to Currie Enterprises to produce the housing and assemble the pumpkin (Truetrac and 3.70 gears in my case) and stub axles. I’ve used Currie rearends in a bunch of projects with zero issues, so they chose well from my perspective.
In related news, my rear brakes from Wilwood ordered last week showed up Friday, but my front brakes ordered before Christmas are nowhere in sight. Frustrating.
i assembled the rear housing, crossmember and mounts. For the housing and pumpkin, Ridetech turned to Currie Enterprises to produce the housing and assemble the pumpkin (Truetrac and 3.70 gears in my case) and stub axles. I’ve used Currie rearends in a bunch of projects with zero issues, so they chose well from my perspective.
Interesting comparing old and new ; just curious; on your thoughts of going with a new diff housing, instead of refurbishing the old - GV
Last edited by roadster65; 01-20-2019 at 04:24 PM.
Your comment is 100% correct. A couple years ago when my Dad was just 83, he called me up and said that his differential was making a strange noise. And that he was doing burnouts in a nearby parking lot and thinks he broke something. His 63 SWC with a LS3 was too much for the original rear end.
01-17-2019, 05:26 PM
