427vette66

Block casting number says its a 396, but some vette guys have told me the casting number was also used on early 427 2 bolt blocks. Would the stamp date and casting number coincide together for a 427. And how can you establish it was a standard bore of 4.25

Says STD bore of 4.250 and is clean, does not need bored clean bill of health from machine shop. No ridge ring, very low miles.
Dates:
3855961 Block Date L275 (Dec 27 1965)
3872702 Heads Date A46 A56 (Jan 4th and 5th 1966)
3866948 Intake (Holley) Date L215 (Dec 21 1965)

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856666

Hi Vette,

I would say 427

The 1966 cast dates I looked at show:
3855961 as a Early 427 (1966) - not a 396
1965***3855962 396 425 Horsepower ******
3872702 390 Horsepower 427 Engine
3866948 Cast Iron 390 Horsepower 427 Engine

See reference below

Phil

http://corvette-world.com/corvette_specifications.php

Joe Inama

Knock out a freeze plug. If no space between cylinders , it a 427. If u can pass a pencil between cylinders its a 396. Bubba way of determination. :-) I bought a basket case 66 that came with a 961 block, was suppose to be a 427, NOT. turned out to be a 396.

corvette67jim

Not going to be considered an "early" motor with a cast date 12/27/65 that is almost halfway though the production year.The 942 casting 427 block had already been out almost four months by this time.

427vette66

Here is the block on ebay. Was messaging him, but thought i was a scammer for some reason. Told me to move on.

http://www.ebay.com/itm/171121160168?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

AZDoug

The only sure way is to pull the cyl head.

You used to be able to use casting numbers,

But....

People started making epoxy casts of the real deal casting numbers and gluing them on 396 blocks.

Doug

Nowhere Man

When I started doing research on Chevelles and 396 about 10 years ago I read all kinds of stories about a 961 cast block as a 427. Since that time and looking at all kinds of blocks I never saw one. So fair I can't say anyone had one. It's a myth that needs to die. Bottom line is there is a Chevelle or impala out there that's missing it's block

And I have a first week of October of 65 a 961 block that's a two bolt 396.