66 vette 427, #3855961

[William B.]

Buying a 65 conv, the owner says original engine was decked and the rebuilder stamped a bunch of odd #'s on the pad. It is a dec. 65 car with a 3855961 block build 2 weeks before car. I checked the car it is an original 427 car, but could this be the original engine? Thanks for any answers, Bill

[Bill Stephenson]

Re: 66 vette 427, #3855961

Bill,

------Am I possibly missing something? Your header makes reference to 66, and 961 block. Then the body of your question talks about a 65. Do you mean a 66 built in 65? If you can give us a few more facts such as build date of the car and casting date of the 961 it would be helpful. Im not very conversant with 961 block cars, but Im sure others are...........Bill S

[William B.]

Re: 66 vette 427, #3855961

I am sorry it is a 66 conv. with a buid date of dec 65 3rd week and engine build 2nd week of dec.

[Joe R.]

Re: 66 vette 427, #3855961

Bill,

Yes, an early car such as the one you are describing can have a 961 block. Check it out in every detail and don't let the 961 block stop you from the purchase of a great little conv.

Regards,

JR

[Mike M.]

Re: 66 vette 427, #3855961

Bill: i've never seen a 66 mark IV block with 961 cast # in a 66 VETTE that i was convinced the car and the block left st louis at the same build date. most likely a pass car block. pad obliteration and 961 cast # would make me more than a little suspicious. mike

[Joe R.]

Re: 66 vette 427, #3855961

Mike M,

Listed on page 60 of the NCRS 53-72 Corvette Specifications Guide. Is mine out of date and superceded by some more information?

Inquiring minds would like to know.

Thanks,

JR

[Dick W.]

Re: 66 vette 427, #3855961

Restored early Oct. '65 427. Did not have 961 block. Very original old car with all the parts that left St Louis with the exception of the altenator

[Mike M.]

Re: 66 vette 427, #3855961

check out p 58 of 66 judging manual. one i have is 3rd edition, first printing. team leaders credentials leave a lot to be desired. regards and see ya in carlisle. mike

[Joe L.]

Re: 66 vette 427, #3855961

Bill-----

GM #3855961 is a 396 cid block with a 4.094" bore size. It would not survive an overbore to 427 bore size of 4.250". Even if it would, there is no way that the factory would have bored a block designed for a 396 engine to 427 configuration. So, there's no way that this engine is an original 427. Also, I feel pretty confident that no 396s were ever originally installed in 1966 Corvettes.

I think that the "correct" casting date on the block is just coincidental. The 3855961 block was still being manufactured at that time but for use in 396 passenger cars and Chevelles only.

[Joe R.]

Re: 66 vette 427, #3855961

Mike, Joe and you too Dicky,

I stand corrected as I was going by the NCRS 53-72 Corvette Specifications Guide published long ago as Volume sixteen, Number One-Summer 1989. I will agree that Chevrolet did not go to the trouble of boring out a 396 to 427 specs and remember that particular block will run hot or crack if bored to that specification.

Thanks for the info,

JR

[Frank H.]

Re: 66 vette 427, #3855961

I have had a 3855961 block stamped 427 390hp years ago,along with a 396 block bored 427 by local machine shop,that I used in my 55 drag car,and the super sport book lists this 396 thicker block as being commonly bored to 427 back in 1966 as does the how to hot rod a big block chevy,even .010 over.
Funny thing it was no big deal to bore one 4 1/4 years ago ,but now they won't do it without sonic testing the block as my friend had one done,as he wanted to trade up from his 396 emblems to 427 in his impala.
He showed me where they have been popping up on ebay with 4 bolt mains and oil cooler holes freshly tapped advertised as rare standard bore corvette blocks but they were never more then 2 bolt 390 hp at most.

[Donald T.]

Re: 66 vette 427, #3855961

I'm wondering if anyone has ever tried to recover the VIN from a decked pad. I've heard of law enforcement using forensic techniques to recover ground off serial numbers from guns. I did an Internet search and there are labs that do this type of work not only on guns, but engines as well to determine vehicle theft. If you do an Internet search for the phrase "serial number restoration", you'll see a lot of information on the topic. You can even buy a serial number restoration kit over the net for about $100.

[Mike M.]

Re: 66 vette 427, #3855961

forgot to mention in my previous 961 post that the 961 casting # reads outboard to inboard whereas the 942 blocks have casting # reading inboard to outboard. recall having judged a 66 vet years ago wherein someone removed the 1 digit from the 961 cast # and in the 1's place a 2 was created with jb weld. fact that the cast # read outboard to inboard didn't occur to the jb welder.invited the owner to pen-knife the 2 and the knife sank in the jb weld. mike

[Bill Stephenson]

Re: 66 vette 427, #3855961

-------I agree with Mike. I didnt want to say anything in my first post but I have also never seen a true 961 cast# block that came in a 66 Vette. Thought maybe there was something I didnt know. My cousins #700 serial number 66, a true 450 if ever there was one, was a 942 cast#. This car being built in December would be very suspect in my eyes. I just dont see it............Bill S

[Frank H.]

Re: 66 vette 427, #3855961

Thought I should add the 427 390 stamped block was out of a full size 2 dr that was a retired sheriffs car and may not have been standard production.
A 66 coupe owner in the club lost his casting numbers when they hat tanked his 425hp block and later met the original owner and got the 390hp window sticker and all the paper work.