Well I finally gave up on finding a local machine shop that was interested in doing a custom build to my specs, they all were trying to steer me back to the factory specs for their warranties, or charging a lot more to do what I wanted. I managed to find a shop offering a crate 400 that they have found a good recipe for power with. It has Aussie heads, overall compression of 9.5:1 (runs on pump premium only), with a comp cam and the various other upgrades. I spoke with the owner and he seemed to be very knowledgable about the 400 and performance upgrades, and has been in buisness over 30 years. He gave me power specs, but I am wondering if someone with the computer program can plug in the specs and give me a second opinion. It will have headers on it when installed. My one big question is carb size. With this build should I go with a standard 600cfm? I've had my eye on the new Holley truck avenger, it is a 670cfm.

Here are some of the build specs. Thanks in advance!

• 9½ to 1 compression pistons
• Seasoned block that has been vatted, magnafluxed for cracks, thermal cleaned and steelabrated, bored, honed and plateau honed to fit new oversized pistons
• Deck head gasket surface on block
• New CompCams Split-duration hydraulic cam, advertised duration of 262 In t. and 270 ex. Duration @ .050" 218 Int. and 224 ex. .513" Int. and .520" ex. valve lift. Ground on a 110 Lobe center.
• Australian 2V closed chamber heads. They are casting #ARDIAE and have the "closed chamber" design of the early 4 barrel Cleveland heads but with the 2 barrel port sizes.
• Heads have been vatted, glassbeaded/steelabrated and magnaflux checked to be free of cracks
• 3-angle valve job
• Both heads resurfaced
• 60cc "quench" chambers vs the American 75cc open chamber head
• New Valve guides
• Assembled with all New 2.040"Int/1.660"Exh valves
• New Heavy duty double row timing set
• New High volume oil pump
• New Edelbrock Performer aluminum intake manifold
• This engine comes with a 2" high intake to carb spacer to increase plenum volume.

 

seems to be a really good build to me. i dont have a desktop dyno or anything like that but im sure someone will be by soon

 

Sounds like a good build. I'd fo with a 750cfm. Maybe match the intake/head ports.

 

looking for some numbers still!

What are you looking for as far as hp, torque and powerband?

 

Closed chamber heads are a waste of time & money on an otherwise stock 400. Unless you either mill the deck .050 or get pistons that come up to close (and I mean really close) to zero deck then you're not getting any benefit from the quench design of the heads. There's no reason a 9.5:1 C.R. ratio engine should need to run pump premium if the engine is built correctly. With the number of cams available which will reduce the dynamic compression you should be able to run it on good ol' 87 octane.

You shouldn't need a machine shop to do "custom work" to rebuild the engine, you just need the right parts, i.e. pistons that come up to zero deck. The rest of the build is just basic machine work & assembly.