[chiphead]

I'd find a different set of heads. There are 3 main problems with using small valve 16s on a 461.

1: Compression will be too high. It will require the use of race fuel at $6 a gallon, or a set of $800 dished pistons.

2: The valves are too small for a 461. Big $$$ for the conversion and porting.

3: The heads need converted for screw-in studs.

It will cost you as much to properly prepare these heads for use as it will to buy a built set of 5C or 6X-8s, or a set of 87CC edelbrocks.

As Will said, the power is in the heads and manifolding. Using low-performance heads on a big-cube bottom end is a mistake. You'd might as well run the 400 as-is.

Ditch that smogger intake into the closest scrap bin. Performer RPM and Q-jet all the way.

The XE274 cam is wrong choice unless you get the compression down below 9.5 with iron heads, or 10:1 with aluminum. The XE cams build cylinder pressure and will detonate on a large, high compression engine. A Crower is likely a better choice for a high compression 461.

And spend the coin on a good windage tray and oil pan. Use ARP head bolts. And have that Eagle crank checked 9 ways to sunday, some had machining problems.

Spend the money on proper block work. Zero decking, torque plate honing, magnafluxing, etc.

You realize this engine is gonna cost $4500, right? Pontiacs cost $10 per HP to build.

good luck, chip.