Numbers,Numbers, Numbers!!!! Which one is Correct??? Maybe Zora Knows!

[Viet Nam Vett]

My Freind is looking for the correct BB 1966 Bell Housing. I posted WTB on the C1 C2 Parts Forum. The Number My Freind has came from the NCRS manual. It is a ..3872444 for BB Bell housing. DaBo Replied that he has one but different numbers. See Post Below... Which One Is It???
From Parts Post.
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The following reply was posted by DaBo:

My records...(GM microfiche) indicate that you should need a # 3899621 for
1966-1981 350,427,454.
1966 427 Special High Performance would be a # 3858403.


Maybe some others can agree or disagree on this.
I am not sure what your number is. (3872444)

David
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Confusing :confused: :confused: :confused:

[JmpnJckFlsh]

The Number My Freind has came from the NCRS manual. It is a ..3872444 for BB Bell housing.

From the NCRS manual...? If it is the 65-66 TIM&JG (judging manual), then that is the part number that originally came on the cars, but I would make sure that I was interpreting the manual correctly.

It is possible that both numbers are functionally correct because it was not unusual for GM to re-issue a replacement part with a new part number. My parts book, which includes replacement parts for all 53-72 Corvettes as of 1972 shows the same thing as DaBos microfiche: bell housing for 66-72 Corvette (350, 427, 454) is part number 3899621; 66 Corvette with Sp. H. Per and L88s is 3858403

The 3899621 bell housing was in production cars by at least 1970. If the later design bell housing also worked on any earlier power trains, then the current production part would probably have superceded the earlier part number to reduce replacement parts inventory.

If this is true, then it all comes down to your friend's preference: original part number or replacement part number? My opinion is that the bell housing part number probably isn't judged since it may not be visible under the car, but if the bell housing can be identified as non-original from any visible portion, he could get judging deducts. He should talk to a midyear chassis judge before deciding which bell housing he needs. I would probably try to find the original part number if I could.

[Viet Nam Vett]

Thanks Chuck,
I'll email your reply to him.............. :cheers:


[Modified by Viet Nam Vett, 12:42 AM 11/2/2002]

[clem zahrobsky]

my list shows that the 3899621 is for a 11" clutch and the 3858403 is used with a 10 1/2" clutch like the L-88 :chevy

[Viet Nam Vett]

Clem, Thanks I sent your post on ............... :cheers:

[Pillman7]

According to Noland Adam's Corvette Technical and Restoration guide for 1963-67 Corvettes in which he publishes the results of some surveys he did while researching information for his book, the correct bellhousing for a 1966 427 L36 and L72 engines was 3872444. The base 300hp and the 350 hp L79 engine used 3858403. The 3899621 bellhousing was for a L89 1967 427 with the aluminum cylinder heads. I hope this sheds some light on your problem.

[JohnZ]

#3872444 was used on early '66 BB's, #3899621 on later '66 thru '74 BB's; they are absolutely identical in every respect except for the casting number (which is not judged, except in "Bowtie" judging). For Flight judging, either one is acceptable.