Thread: Need tips on building a 406 small block chevy

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Hi. I'm new here and my name is Mike. I recently retired, bought an 88 Corvette and am looking to build a big horsepower 406 to put in it. Any tips on putting together a 406 that will give me around 500 hp? I would appreciate any input you could provide as it's been many years since I built my last block. My how things have changed, especially the cost of parts nowadays.

Welcome Mike.A few questions.Do you want to run it on pump gas??.Do you mind adjusting a mechanical lifter rockers cam??.How much do you want to spend??.Do you know about the aftermarket big SBC blocks??.Just better overall.

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

should think about a SHP block you can bore it to 4.165.bigger jackets for cooler running far and away stronger block and comes with the 350 main to .you can use the scat I beam rod scr5a7 5.700 or scr6a7 6.000 rod cut for more cam room runs a short 8740 ARP cap screw.a cast steel crank if low dollar build i go with the icon piston or mahle power pack piston kits or same piston made for PBM abit less money . block will be your big cost less you have a good 400 block hard to fine a good block . i have made up 400 cid kits with shp blocks along with the shp 200 runner heads that i sold on E bay and on my webpage the great deal going to the shp block is you can go past 406 easy and TQ numbers are not hard to get when your past 420 Cid the only down side is for the money. i can build a 496bbc with all Gm block heads rods. more cubes same or less money has to do with how wild you want to get the 500 hp numbers is very ez to get as well . or go Ls small block if you want a small block size

The SHP block option is a better way to reach your goals torque being the main objective.Here there are three experts in building engines.Those are Pat,Jerry,and Techinspector1.For you to look at the newer LS series engines is also a very positive step.They have been around now for awhile and available at reasonable prices second hand.Mods on them do produce substantial outputs much easier than the earlier 400 blocks.If I have one regret it is not to have built a LS engine and have built a 383 stroker.