66 427 engine

[Harry Koba]

I'm restoring a 66 427 coupe. I did not have the correct engine when I bought the car in 1976 so I'm in the process of building a correct one. The car serial number is 102465 and the body paint and trim plate BO5 S451 (10/05 St Louis )

The date code on the block ( 3869942) is I15 5. It came out of Corvette 3400. This block was not originally machined for a 450 or 425 ( two bolt main, incorrect size pipe plugs on and around oil filter housing), it is now.
My questions are: I believe the decal on the air cleaner for an early production 66 had 427/450 not 427/425?
I realize that September 15 casting date and October 5 body paint and trim color date is pretty close. What assembly date do I get stamped into the block stamp pad? I was thinking T0925IP 6102465. The 427 I originaly had in the car ( not out of a Corvette ) had the assembly date 9 days after the block casting date. I live near Minneapolis, where can I get the engine correctly stamped?
What starter # should this engine have? The NCRS Tech Manual says 1107365, but the Delco book says that's for a passenger car, a Corvette's should be 1107352?
Thanks

[Joe L.]

Re: 66 427 engine

Harry-----

Your early October, 1965-built car likely would have originally had the 450 hp A/C decals. The change to 425 hp decals occurred about late October, as I recall. The ONLY difference is the A/C decal; there is NO other difference with respect to the engine or any other L-72-related components on the car.

I think that 9/25 would be a reasonable engine assembly date considering the build date of the car and the casting date of the block. You could also go a little closer to the 9/15 block casting date. Remember that in those days, Tonawanda had both a foundry and an engine assembly plant; the two were right next door to one another. It actuallity, there usually was a significant time lapse between casting and assembly for big blocks (often longer than the usual time lapse for Saginaw-cast and Flint-assembled small blocks). However, I'm sure that there were a lot of big blocks that were machined and assembled the day following their casting.

I believe that all 1966 Corvette big blocks used the GM #1107365 starter. The GM #1107352 was used on 1965 L-78. It has identical specs to the 1107365 with respect to starter performance. However, the 1107352 has a starter nose for use with a 153 tooth flywheel as was used by all 1965 Corvette L-78s. The 1107365 has a starter nose for use with a 168 tooth flywheel, which was used for all 1966 Corvette big blocks except, perhaps, any that MAY HAVE been originally built with M-22 4 speed or Powerglide automatic transmission.

[Mike M.]

Re: 66 427 engine

joe: re the "450" hp a/c decal.i don't believe any 66 solid lifter mark IV's left st.louise with 450 hp ac decals. do you have any documentation to convince me otherwise? mike

[David D.]

Re: 66 427 engine

Harry, The engine assembly date T0922IP is on most, but not all, L72's with the I 15 5 block casting date, in that serial # range. FWIW. Dave

[Joe L.]

Re: 66 427 engine

Mike-----

I think that it's pretty well recognized in several authoritative publications. As I recall, it's covered in Noland Adams' Restoration Guide, but I haven't looked at it recently.

Beyond that, I had a good friend that worked with me at Safeway Stores when I was going to college who bought a new 1966 L-72 at the beginning of the model year. I remember the car well. It was mosport green with green interior. It had 450 hp a/c labels.

[Craig S.]

Re: 66 427 engine- see the new Restorer

Very interesting article in the Restorer that just came by Everett Ogilvie on this topic, based on his two personal cars...Craig

[Everett Ogilvie]

Re: 66 427 engine- see the new Restorer

Thanks for the plug Craig. Actually, much of the info is based on informal surveys from many owners, as opposed to just my two cars. I do though, believe that some cars came off the line with 450 stickers. The confusion around the issuance and implementation of the ECR would lend itself to the possibility that a few cars escaped with the dreaded sticker - see the article for details. As the originality of these 450 stickers is almost impossible to verify today (many have been changed, and some have been aged to look old and original), it is best to rely on factory paper to identify cars that left the plant with the 450 rating - a paper-only difference, but an interesting, rare item nonetheless.