Factory Intake or Replaced ?

[72 Cheyenne K20]

Hey Guys,

I just bought a 1976 GMC K15 that is the most complete and rust free truck I've ever bought. I'm probably going to end up restoring at some point.

I ran the engine suffix code and it is the original 400 C.I. enginewith a build date of 01/26/76. I ran the intake cast number of 346250 and it shows 76-82 All applications for a 305/350 and it has a date code of K245 (10/24/75).

The Rochester 4 B Qjet on it now is not the factory original. It's off of a 1973 something or other.

My question is: Could this be the factory intake? Is 3 months too far between engine build date and manifold production date to have been put together? Is this a correct cast number for trucks?

Thanks in advance and let me know what you think.

Scott

[bhc41051]

I believe in 1976 a 1/2 ton with light duty emissions would have a hot air choke. I think in 1973 all chokes were the spring type. The 346250 intake looks like it takes the spring type choke.

[ray_mcavoy]

Yes, the 346250 intake is correct for trucks. It has the flat mounting pad for a divorced (spring type) choke thermostat. It also lacks provisions for an EGR valve. This would be correct for a heavy duty emissions application.

For 1976, I believe any GVWs over 6,000 lbs were considered heavy duty in terms of emissions standards. And I think most (maybe all?) K10's & K15's this year were rated at 6,200 GVW, so that could very well be the original intake manifold for your truck.

[72 Cheyenne K20]

Thanks for the input Ray. I did some more research and would have to agree with you. 346250 was a truck manifold, spring choke, and no egr valve would be a perfect match for the 6200 lbs rating for this truck. I was also wrong on the dating. It should have been 11/24/75 which would make it about a two month window of assembly between the block and manifold. Thanks again!

Scott