My friend has a 400 sitting in his garage and says I can have it. He says that it was out of a Pontiac, but is sure it is a small block (well in terms of size, there is no Pontiac blocks, just block) I am wondering is this definately a Poncho 'big' block or could it be a SBC? What came with 400 SBCs, anyway?

 

those were your primary 400sb origins.

If it has anything but 4bolts on the valve cover it is not a chevy.

And if its a pontiac your best approach is to make it a 455 and don't rev it over 5250.

.

 

No Pontiac came with a 400 small Chevy motor or vice versa.If it looks like your engine it is possible it is a 400 out of a Caprice,Chevelle Laguna,Truck or Van
If you don't want it,I do!

 

the big cube pontiacs are Not big blocks or small blocks they were wide blocks

 

buick, pontiac, olds, and chevy all had 400's if its a chevy look for the distrib coming out of the back on the intake, and a GM and a bunch on numbers on a pad on the driver's side top rear of the block, if its a pontiac look down by the motor mount on the driver's side, it will say what size engine it is cast into it.

 

..and if it is a Pontiac engine it will have a valley pan under the intake, a cast aluminum timing case, and a water pump that fits into the timing case with no space behind the pump.

 

It is a small block. It was his uncles old Firebird, and some one had swapped in a 400 Chevy when the 350 blew originally. His uncle scrapped it because it went though 4 transmissions in a decade, and it got so rusty he is parting it out.

I called the guy who is giving it to me and got him to go out in the -20 oC weather, and count the freeze plugs, and measure it's length. The real deal, it's an SBC!

It would be cool if it was a Pontiac, but the only Big Block I would put in the Camaro would be a 396, or a 427. A poncho 400 Third gen Firebird would be really cool!!!

So now I have a 400... What now? Any suggestions? I have some plans but I will get to them later.