Thread: Need tips on building a 406 small block chevy

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cost of parts have not went up much at all .think of it this way what is your time worth ? or the guy at the machine shop? i spent as well as others many hours of time reworking stock parts and old TRW pistons . stuff you can buy now needs less then 1/2 the work and 2 times stronger and a way better part for size and metal alloys not to long ago about 25 years you could never buy 4340 cranks and stroke sizes you can fine now. it would be custom billet crank . or pistons or rods . heads and cams have come along way now. were 30 years ago you could not buy a head that flows as good as some of the stock stuff no matter how deep of pockets you had

Welcome Mike and congratulations on the retirement! There’s a whole lotta hot rod knowledge and some real engine builders here that will be able to get you where you want to be.

I’m no expert on 406 – but have done a couple builds of the 400 SBC with mixed results. The 4.125 bore necessary for a 406 scares me on an unknown block so I’d be inclined to look at a short block assembly. There’s a company called “Coast High Performance” Chevy Short Block - Chevy 406 Short Block, Chevy Small Block Stroker that seems to have a real good handle on the 406. I have not used them so cannot endorse, but it may be worth your while to give them a call at 866.249.9143 extension: 2907 and talk with Eric Cady and see if they might be able to put together a strong base for you to work up from. They’ll be all over the clearances and probably have a suggestion or two about small circle hydraulic roller cam that work well with a 406.

As to the 500 horsepower – might be tricky and still maintain some semblance of street manners. I think 400+ will be fine and more importantly, 500+ lb-ft of torque (which is really what you want!). There was a time I would have said “go Vortec” – but with some of the new AFR heads, I might lean toward Airflow Research 195cc heads. As the name implies, they have 195cc runners and you can get them with a 65cc combustion chamber. If you’re gonna drive this thing hard, get the upgraded springs from AFR (part # 8605) to eliminate any valve float issues. No matter which heads you choose, they will have to be drilled with steam holes to match up with the block's steam holes. The 406 also requires special head gaskets with a 4.200-inch bore and the appropriate steam holes between the cylinders (Fel-Pro part number 1014).

I’d use an Edelbrock RPM Performer Air Gap intake manifold, and a Quadrajet carburetor. I’d stay with a GM HEI distributor with 8 degrees initial and 35 degrees total (may be influenced by your cam selection) and tuck some Hooker ceramic coated headers (part number 2151-1HKR) underneath. Yup – they’re expensive but they’ll fit and be the last one’s you buy. Slap a couple 40 serried Flowmasters on and you’ll be ready to rock and roll.

Have fun and let us know what you decide!

Regards,
Glenn