Does anyone know if a 1956 intake manifold would fit a 1955 287 I’m looking to convert to a 4 barrel carb Thanks 

Casting number 521571 should be the number for a 1956 Pontiac 4-bbl intake off of a 316 Pontiac V8. The 287, 316, 347, and 370 were the part of the Strato Streak V8 engines. It should fit your 287.

The casting number is usually near the #1 cylinder intake runner - by the thermostat. 

Thank you Frosty

You are welcome sir. We'd love to see pictures of your project.

Here’s one 

Sweet looking ride Poncho Pete. Tells us all about it and when you get your intake installed, let us know how she performs.

Hey Frosty this is what I have so far

Thanks for sharing Pete.

What you are showing appears to be the engine head casting number. The casting number on the intake manifold I am referring to is like in the picture below. So in this photo, the intake manifold casting number is 9790140. You are looking for casting number 521571.