Thread: big Block Help

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Hello guys I am new here I found this site while searching for info. I am a mechanic and a man traded me a built motor for some work and the man in his 90s said it is a 400 his son said its a 350 well I can tell for sure it is not a small block the only cast numbers are passenger side and they are 979096 or 979996 I am told that is not enough numbers but that is all that is there on the drivers side for the date stamp is 1119 all numbers are fairly clear between the date and block cast number is the letter D and N with a pointed arrow between them and the stamp of circles for the time made I have been searching for info I would really like to know what I have all info greatly appreciated and also the old man said it came out of a 1970 Pontiac Le Mans and had it rebuilt

As far as I know, all Pontiac blocks were the same external size. Maybe some Pontiac experts will chime in.

Pontiac Power
here are the pontiac #s go to bottom of page

Looks like a pontiac 400 but all the 979 codes I find are 7 digits. Maybe you missed one.

Jack.

Forgot to ask, what are the cast numbers on the center ex. ports of the heads?

Jack.

I did look at that site and we have looked cleaned scrubbed only 6 numbers

the sites that i found had 6 numbers and 7 number codes I will check again and look for the other numbers in the morning and report back but I am positive there was only 6 numbers

Maybe the number is 9799916 which would make it a 70s 350. How about a few pics?

So pontiac blocks were the same external size small blocks and big blocks? That could be dissapointing I will get some pics this morning and post them later

I'm not positive but the numders on the heads may shed some light on what the block is. I believe the 400 heads don't work on the 350 block ,,,but them I haven't worked on one if a few years

Have you found the ex. port numbers yet? Doesn't guarantee anything as the post 64 (65)? heads are interchangeable. 301s excepted. Also, although some other heads may bolt up, the heat crossover ports to the intake might need to be blocked or adapted. Not even talking about round (ex.) port heads as they are rare.

Jack.