[Head recommendations for an SBC 406]

I think I would go with the Brodix. They have a good reputation, there is only 5cc difference and you have plenty of cubic inches under those heads to keep the intake volume moving at a good speed for proper mixture. The best part is you will save $250.

[Head recommendations for an SBC 406]

Now that I know that you are talking about a boat things are different. You need smaller intake runners for the low rpm. I80 cc like I have would work great. There is a much bigger issue here because this is going in a boat. The type of cooling system to be used needs to be considered. If you are using lake water you can not use aluminum heads. Electrolisis will eat them up and cause hot spots in the chambers, pre detonation ultmatly distroying the heads. The dirtier the water you run the faster it will happen. If you are running in Lake Tahoe you would probally be ok but anywhere else and the motor will distroy it's self. So the options are cast iron or get a closed cooling system. After I built the motor in my boat using the iron eagles I found out about the closed cooling system. Then I could have used the aluminum heads. The cooling system was one of the best devices I put on my boat. The block has anti-freez in it like a car. Winterizing has become a minor chore and the motor runs a constant temp.

But there is more. Cam choice is criticle in a boat. If you are running water injected headers, water can get sucked back into the cylender through the exaust valve if the cam loab center angle is to large thus hydr-locking the motor. Information about boats is hearder to come by but its out there, check some hot boat sites. The more research you do the more money you will save in the long run and enjoy the boat for a longer time.

I have an old classic Century Resorter, direct drive with the 388. It is a total sleeper. It pulls a skiier out of the water better than all the new competion ski boats and has a top end of 50 mph on gps at a 5000 ft elevation.

My friend that I boat with has a old classic V-drive drag boat with a blown 440 which he built. Both our boats run flawlessly. You dont want to have trouble on the water. It's hard to walk for help.

I am no expert on boat motors but I have a little experence with them. Of course you know that for low end toqure nothing beats a big block.

[Head recommendations for an SBC 406]

I have run Dart Iron Eagle heads 180 cc runners on a 388 The bowl and intake were heavly reworked for a heavy boat that runs up to 5500. They work great and heve for years now. The engine builder usually used 220 cc intake runners for race engines turning 7000. I called Dart and asked them what they recomended for the purpose I needed and Dart recomended the 180 cc. Dart was right, they work great for the low rpm I use them at. But if I was building a 406 to go in a light Z car, I would go with aluminum heads to save weight and they can disapate heat better than cast iron, 220 or larger intake runner with at least 2.02 intake valves all roller please. Place a cam that will provide max hp at 5500 to 5800 rpm. Something like 280/280 on a 106 LCA. The toqure will come on a little later in the rpm range and save some rubber on your tires. There is a great easy to read book with dyno charts called How to Build Max Performance Chevy Small Blocks on a Budget by David Vizard.

[Did I ruin the G-nose?]

Looks OK, but does not flow with the rest of the design as others have mentioned. The bottom two photo look great. The bottom one looks like it flows the best with the rest of the G-nose design.