I need to build a 406 sbc please help

[Sal's '55 Chevy]

I want to build a 406 sb, what do I need to do? As far as the boring and everything else, balancing, casting number, crank, heads. The motor will be going in a 68 swb truck that will be a weekend cruiser only. I have a turbo 350 with all the goodies already. What heads do I use stockers or aftermarket? I would like to keep it fairly reasonble cash wise. Thanks

[redhead69]

Whats your budget? A 406 is just a .030 over bore on a 400's standard bore. Heres my combo- very cheap way to go and has some punch for a cruiser-

400- 2 bolt block .030
stock crank, rods, cast pistons
350hp 327 cam (better choices are out there but this one works good)
stock 76cc heads with full roller rockers
dual plane alluminum intake
650-750 holley
hei

runs high 13.s all day and 60 miles round trip to the track.

Now if I was to build another one it would have some 5.7 or 6.0 rods, forged/ balanced bottom end with some good 64 cc heads along with a .520ish lift cam

[Wild83C10]

Why a 406, do you have the block already? Do you have any parts yet?What is your budget $3k, $6k? What are the plans for the truck? cruiser, strip? More details the better.

[Marv D]

Finding a usable 400 core is quite a feat these days. To do this 'right' and have a platform that will tolerate most anything you throw at it,, start with a Dart SHP block ($1500ish machined and ready to go) The SHP block will accept the 3.75" stroke easily, and I am just finishing a 434 for a buddy,, NOT fun in the SHP block but doable. Stick with a max of 3.875 stroke and you'll still have some hair left when your done.
Heads are where the power is made,, pick your poison. AFR is a GREAT line, as is the new Brodies. You get what you pay for,, choose wisely.

In todays world I refuse to build a flat tappet cam motor,, hydraulic roller for the street, and solid roller for the more 'performance' oriented. It adds cost, but is the most reliable in the world of oil that is designed for roller motors and ignores the needs of a flat tappet cam.
You've already spent $5k,, might as well do it right,, Scat and Eagle cranks are made in the same foundary. Scat is final machined here,, pick a Made in USA crank like the Cola or Crower,,, but it adds cost. Lunati ProMod rods, SRP pistons,, and you'd dumped another $2-3k in rotating assembly with a good ATI balancer, flexplate and balancing. Then pretty much all you need is induction and exhaust. Don't get stupid,, you don't need a SuperVictor on the street unless your spinning 7000rpm. A Victor Jr is a good intake for street 400, or even a ported RPM is a good intake. Stay away from the imported clones,, there just ripping off the American companies that designed the intakes and do a poor job of it at that. A 400 will perform nicely on the street with a 750 carb, but of your track oriented,, think about something more like 850 or 900cfm, even a custom carb would be nice.

What's the matter,,, you don't have a extra $10k laying around???? Maybe I shot a little high. Wht IS your budget?

[Wild83C10]

I agree with Marv regarding the block and cam. A good 400 core with machine work wouldn't be worth it.

If you are on a budget a 383 is the way to go, you can use a new GM 4 bolt block.

If you are going NA and looking for 500-550 ish hp/tq then you could save some coin and go with cast parts. If you are planning power adders in the future forged is the only way to go.
Checkout racingjunk.com. Some shops on there are selling complete 415 motors, intake to oil pan (assembly required) with all forged internals, Dart SHP block for $5k. No way you can beat that.