Casting vs Assembly vs Car Build Dates

[Joel Falk]

Hello everyone,

Like most everyone here, I am interested in better understanding how these cars we love so much were actually built. Please have a look at this ebay auction for a 1967 '351 block. http://cgi.ebay.com/ebaymotors/1967-...spagenameZWDVW

The block was cast on J 7 6, or October 7, 1966. Per the stamp (which I have no doubt is authentic), the engine was assembled on 12/19/66, and by my best estimation, the vin of 107530 was assembled the first weeks of Jan. According to the JG, these numbers all jive as the cast is less than 6 months prior to engine assembly, which is earlier than vehicle build.

My question is how things were really done in Tonawanda and St Louis. The block was cast over 2 months prior to engine assembly. Would a bare casting have just sat around in Tonawanda for 2+ months prior to being built? When would it have been machined? Just hours/days prior to assembly or were they machined closer to casting? Also, why would this 390 car have a 4 bolt block?

After engines got to St Louis, was there a FIFO type of relationship for installation, or is it possible for two cars with a build dates just a few days apart to have engine build dates (and casting dates) weeks or months apart?

I have been taking digital photos of pads and castings for some time now and while there are some trends between the numbers, I have examples of bigger gaps than these.

Thanks,

Joel

[William C.]

Re: Casting vs Assembly vs Car Build Dates

Blocks in Tonawanda could and did sit around, in addition, there is some evidence that the Mark IV engines may have been "batched" at the casting plant since volume was not high in the early years. Machining would have been just prior to engine build as ther was little room for inventory of machined unassembled castings. No FIFO anywhere in GM at time these engines were produced, plus there is the variable of rail shipment which could be haphazard with respect to delivery.

[Philip C.]

two bolt to four are done all the time

Joel what you have here is a two bolt block that was drilled to four bolts later in its life. Phil 8063

[Mark #28455]

not original 4 bolt block

All 396 blocks hav machined reliefs for the valve clearance in the decks. ONLY original 4 bolt 427 blocks had these reliefs, this block does NOT have them so was NOT an original 4 bolt block from the factory.
Mark

[Joel Falk]

Re: Casting vs Assembly vs Car Build Dates

Bill,

Thank you for the information. The relationship is becoming more clear to me. To use concrete examples though, would it be unusual to see cars with engine assembly dates having vastly different casting dates? Based on your comments, it seems like the relationship could be quite random.

What is the realistic range of time between casting and assembly date that we could expect to see between casting and assembly? My feeling is that the 6 months in the JG is for the exception, and realistically it is a month or so.

Joel

[Mark #28455]

depends upon HP

The hydraulic lifter engines were also used for MANY pass cars so were a higher volume production. Typically within a few weeks from casting to stamping. Solid lifter engines seemed to have more variation. I have a June 68 cast 435 HP stamped late Oct 68, but my Jan 69 cast 435 was stamped Feb 69.
Mark

[Joel Falk]

Thanks guys *NM*

muchas gracias