63 Power Booster & Sill Plate Screws
I have aquired a 1963 Power booster the Judging manual states that STD booster number is 5462025 and ZO6 is 5462110.The booster I have the tab Number is 2574 where the judging manual statesit should be 2025. Can some one help me with this number 2574 is it OK for a Late build 63 car . Also can some one tell me the size of the heads of the screws that hold the sill plates down on a late 63 four holes unit.
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Re: 63 Power Booster & Sill Plate Screws
63 buicks had a power brake booster identical to the 63 vettes in terms of configuration. perhaps that is what you have.mike -
Re: 63 Power Booster & Sill Plate Screws
Go with the 2574, the manual is incorrect. They were all 2574 in 63.
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Re: 63 Power Booster & Sill Plate Screws
Hello Murray, I have only seen the 2574 on 63 Boosters. I currently have 2 power brake cars both I have personally known since the early and late 70's so I'm sure these parts are original to the cars. One is a Z06 and the other a standard fuel car. Both have the 2574. I also have a spare booster someone gave me that they took of a car in the 80's and that on also is the 2574 stamp.
I hope this helps, JoeComment
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Re: 63 Power Booster & Sill Plate Screws
Murray, old man, as others have said, the 2574 number is correct. There was an erratta sheet to the old Judging guide to correct the numbers called out for '64 (from '4310 to '4310 or '4311) and for '63 the call was for '2025 or '2574.
The current edition of the JG reads '2025 or '2440 for 1963 but the NTL published a correctional note to make that read '2025 or '2574 as it did in the prior edition. Sounds like your Judging Chairman down unda missed the update info...
On the sill plates, the current edition of the JG agrees with the prior edition (6-hole sill plate didn't happen until mid-64) which would seem to make the use of a 6-hole plate incorrect for any/all 63 cars. Next, there IS a descriptive text difference between the two versions of the JG....
The prior edition of the book read:
"In mid-1964 two holes were added increasing the mounting holes to a total of six. The screws and mounting is the same as earlier sill plates."
The newly released edition of the JG re-words the text and essentially drops the reference to the screws being the same.
Since you have both a '63 and a '64 (wife Wendy's car), you ought to be able to compare the PN call out in the two AIM books and confirm they're the same. If so, there shouldn't be a question of the mounting screws being different for the 4-hole vs. 6-hole sill plates!
In my '65 AIM, the sill plate mounting screw is called out as PN 9414766...Comment
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Re: 63 Power Booster & Sill Plate Screws
Interesting new fact here, Murray! I just used one my 'where used' software utilities to look up the sill plate part I mentioned, 9414766.
It shows up as being used on Corvette and no other Chevy passenger cars from 1964-67 and began usage on 3/27/64. This suggests that the change in the JG where the prior assertion that the screws used to affix the sill plate were the same for 4-hole and 6-hole versions was dropped was done for good reason! It suggests the 63-64E cars used a different fastener for the sill plate than 64L-67 cars did...
Now, if you feed us the PN called out in your '63 AIM, we can probably identify either the exact configuration of the original fastener and/or where originals were also used...Comment
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Re: 63 Power Booster & Sill Plate Screws
The old sill plate screws were 9417945 changed by ECR 6265 on 3/27/64
The new (6 hole) screws are 9414766 as seen in NPC-403.
The sill plate change (to 6 hole), 3797499, was by NPC-366 with a drawing change dated 4/22/64. No ref to 4 hole part number in 64AIM page D69
Believe the difference between screws is that the later screws are #8 with a #6 head while later screws are pure #8. Now that we have two part numbers somebody who has a Gr. 8.900 list can confirm (wish I had one of those)Comment
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Re: 63 Power Booster & Sill Plate Screws
OK, that helps (the prior PN of 9417945). But, Pandora's box opens further...
I have P&A Section 8.9 in .PDF searchable format from 1964! Plus, a few handy dandy other computer searchable utilities. Here's what I found.
(1) The later fastener from the 6-hole era, 9414766, is a #10-16x1 oval head, cross recess, fastener that's chrome plated.
(2) It was ALSO used on Corvette to hold the seat back bumpers to the bottom seat frame.
(3) It was NOT used on Chevy passenger cars of the era!
(4) There was no 'hit' in my Sect 8.9 fastener data base for the 9417945 screw! Nor, did I find it by manually searching through my paper copy of Section 8.9 from 1961.
(5) But, the 9417945 was also used on '63-64E Corvettes to hold the seat back bumpers to the seat base.
(6) The seat bumper fastener changed from 9417945 to 9419263 before finally becoming the 9414766 part (a cost reduction from a chrome plated to less expensive cad/zinc plated part???).
(7) There was no 'hit' in either of my copies of Section 8.9 for the 9419263 fastener either...
So, if we believe the factory complied with the AIM in 1963 for fastener usage in these areas (sill plate and seat bumper), anyone with a known original 1963 should be able to pull a sill plate screw and verify it matches their seat bumper screw(s) then give us a physical description of the fastener...
OR, perhaps our resident parts guhru, Joe Lucia, has access to a more complete GM fastener list that would yield a physical description of the 9417945 screw!Comment
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Re: 63 Power Booster & Sill Plate Screws
The correct booster tab number for all 63's, including Z06, is 2574.
The 2025 booster tab number that you mention is not an original booster for 63 Corvette.
The correct booster tab number for all 64's is 4311.
There was no such thing as a 4310 booster.Comment
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Re: 63 Power Booster & Sill Plate Screws
Pulled the screws from my seats (and an extra seat) they all appear to be the #10 oval heads. (Was not sure) The screw diameter is .195 at a length of .9 with a head diameter of .317. The pitch of the screw thread is about 5/64.
Not use to what the screw specs are relative to real dimensional values hope these will help Jack.
Guess we have not been able to get comments from Joe yet.Comment
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