My book of casting numbers doesnt have anything for an engine I am looking at. The number is 3959512. Can anyone help?

Thanks in advance,

 

I believe (but am not positive) its a big $$$ '67 427 Vette motor among others.

 

Its a small block, Im sure its a 327.

One other quick question. When did GM stop putting the hole in the back of the block for the road draft tube? I presently have a PCV valve in this location and want to find an engine with the same hole.

 

You are right...brain fart....

 

I little tappy tap of the google bar (search on that #), and presto! JohnZ's advice from his much loved Z28 forum pops up:

JohnZMar 26th, 04, 11:35 AM
3959512 had few, if any, production applications; it was used primarily for service replacement short blocks for about eight years, only in 2-bolt configuration; any 9512 that's a 4-bolt was converted in a machine shop (GM never made ANY 4-bolt 327's).

 

If this block has the PCV hole in the back than it's one that I have been searching for. While it is or was a GM 327 replacement block the bonus is that it has large journals which lets you build it up as a 350 cu in and still have the provisions for an early 327 PCV system.

 

First of all, what is the casting date????

This is a "routine" casting number for the 62-67 327.
But, as also mentioned above, this was a replacement block for 327s--------------------------------BUT, in some cases, with a twist.
ALLLLLLLLLLLLLLLLLLLLLLL small blocks up through 67 had small jorunal cranks only. Yes, of course, there is an exception to every rule. The 1967 ONLY Camaro SS350 got a large journal crank. Furthermore, some of the 512 replacement blocks got the large journal crank, plus they also had some features that were unique only to the small jorunal cranks, such as the rear hole for the crankcase ventilation and the oil seperation canister. Last, these replacement 512 blocks have the oil filter pad cast/machined for the 68-later style screw-on oil filter (the production 512 blocks used the canister style filter).

**************************************** **************
THE 67-EARLIER AND 68-LATER OIL FILTER PAD ON SMALL BLOCKS IS TOTALLY DIFFERENT----------------BOTH CASTING AND MACHINING.
**************************************** **************
I have one of the replacement 512 blocks on a stand with a casting date of Jan 1967, which is LONG BEFORE the small blocks switched to the big journal design. It is a big journal block (68-later sytle), oil filter pad for spin-on filter and rear hole for crankcase ventilation/road draft tube.
One great thing about these replacement 512 blocks is that they are IDEAL for building a 383 to be used in a 67-earlier car. For example, this would be an excellent choice to build a 383 to go into a 57 Chevy and it could easily be made to look like a stock 283. It would permit the use of the stock road draft tube setup as well a solid valve covers WITHOUT holes. Use a 68-earlier intake manifold (for either a Q-jet or AFB) with the oil fill tube up front and many "experts" would never have a clue that it wasn't a stock 283 (or a stock 327 on a 62-67 Corvette or 64-67 Chevelle).

 

My 512 CE shortblock is a small journal setup, cast date March, 1970.

it is for sale, BTW, if you know of anybody that wants one.

Doug

 

Thanks for the info. The casting date is L 8 0. What date is this, 1970? I dont think the block has the road draft hole. I have only talked to the person over the phone so I have not seen it. So when did GM stop putting the road draft hole in?

 

Several changes occured with the 68-later small blocks.
In 68, all small blocks got the large journal crank, spin-on filter replaced the canister filter and the hole for both the oil vapor seperator in the lifter valley and the hole for the road draft tube were eliminated.
Beginning in 68, all small blocks had the crankcase vented through holes in the valve covers. That was the very beginning of cluttered up engines. The rest is history.

 

I have one of those blocks. It came with a 68 I recently bought.It has the vent hole in the back, and is dated 1969.

 

And is it a large journal block??????