engine block 3994257 what in the world?!

[scottmitchellrose]

I have a 61 C10 with this casting number- think it is a 250, but the info. on the internet is sketchy at best. The head is F288 and the other side of the engine (driver side- underneath the exhaust manifold when taken off) is 72 and 4257.

Under the 3994257 it says GM then the 3rd line is either 64 or 84- I can't tell if it's an 8 or a 6.

Seems to be a 67-72 inline 6 250; don't know what year. Does the 72 on the other side mean it's a 72?

Thanks,

Scott

[Captainfab]

A '61 would have originally came with a 235. Are you sure it is a newer I6? The 235 will have a front engine mount below the balancer and pulley whereas the 250 will have side mounts.

[TJ's Chevy]

Dead give away for a 292:
6 inch tall side covers
Fuel pump at the center of the block
Bypass hose from thermostat to water pump

Dead give away for a 230 and 250
4 inch tall side covers
fuel pump directly behind the dizzy

250: D dished pistons
230: Flat top pistons

According to the brotherhood....that's a 67-72 Engine possibly Canadian. And it's a 250.

[scottmitchellrose]

Thank you