406 SBC build... Which block would you choose?

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ChopperScott
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406 SBC build... Which block would you choose?

Post by ChopperScott »

Hello there. I've got a complete small block Chevy top end off an engine that I threw a rod through. I am now entertaining the thought of another build. The parts I have include...

•AFR 220 Eliminators, 1110 competition ported heads, 8027 spring upgrade, titanium retainers, 65cc
•Crower stainless steel full roller rockers, 1.5 ratio
•AFR stud girdles
•Comp Cams 300BR-6 solid roller, 260/270 @.050, .630/.630, 106° lsa
•Comp Cams roller lifters
•Weiand Team G 7531 single plane manifold with 2" raised plenum, port matched
•One complete virgin Chevy 400 2-bolt engine (never disassembled)

•Rotating assembly... to be determined

I'm looking to build a high compression 406 cu in full race engine for nostalgia bracket racing.

-My first option is to have the Chevy 400 block machined for 4-bolt splayed main caps, punch it out to 4.155, and drill steam holes in the AFR heads.
-Next option is to purchase an aftermarket block and have the required machine work completed

If this was your build...
-Which option would you choose?
-Which aftermarket block would you choose?
-What are the pros and cons of each?
'73 Camaro Z/28 NETO/N
434 SBC 11:1, 1.294, 6.178 @ 108.87, 9.81 @ 134.93 (3060#, Naturally Aspirated, Sunoco Ultra 94)
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stealth
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Re: 406 SBC build... Which block would you choose?

Post by stealth »

Aftermarket Block of your choice
Get rid of those Comp lifters
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Re: 406 SBC build... Which block would you choose?

Post by BillK »

Scott,
Take a look at this block I have in the classifieds:

viewtopic.php?f=31&t=63737
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Re: 406 SBC build... Which block would you choose?

Post by rebelrouser »

I would never build any engine over 600HP with a stock block. With the cost of a rotating assembly, valvetrain, and cylinder heads you would lose if the block failed, it is just not worth it. And I have been messing with engines when there were no aftermarket blocks. I have been through all the tricks of main girdles, block filler, etc. and when you take a block engineered for a certain HP and then double the engines output, you are just asking for a failure. Hardley anyone tries to build 700HP with a stock cast crank, so why try it with a stock block? I remember the first aftermarket block I purchased; it was the best investment I ever made in my race car. I used to have to rebuild every 300 runs, and usually the block had issues which needed a different block, now 300 runs it looks like new on the inside.
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Re: 406 SBC build... Which block would you choose?

Post by F-BIRD'88 »

Build a 383 using your stuff..
Use that 400 sbc for a 10:1 pump gas street motor or sell it for that.
Use the money to build your racey 383.
I'd build it for pump gas too. Buying race gas gets old fast even for a bracket racer.
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Re: 406 SBC build... Which block would you choose?

Post by lefty o »

aftermarket block. by the time you pay for splayed caps, and machine work on that 400 you're not far off of an shp or similar. for a few bucks more, go for the better block.
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Re: 406 SBC build... Which block would you choose?

Post by rustbucket79 »

I did the splayed cap deal on a factory block for myself, was less than pleased when a stain appeared about a half inch below the deck during the first season. The point being, no amount of magnafluxing and upgrading will substitute a quality block.

SHP is a great option, may as well consider the 3.875 stroke while you’re at it.

I will respectfully disagree with bird, my fuel consumption on a normal bracket day making it to the finals is maximum 4 gallons, and as such I would never back away from race gasoline as a cost saving measure when building horsepower for a competition engine. Youlive in Jersey, you won’t face the punitive pricing we face in Canada. Have a look at the Wiseco Lil quick 16 pistons, a very nice piece for the money.
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Re: 406 SBC build... Which block would you choose?

Post by Monza355 »

stealth wrote: Wed Dec 01, 2021 3:30 pm Aftermarket Block of your choice
Get rid of those Comp lifters
Have you had bad luck with comp lifters ?

And OP is the 8027 spring upgrade to what they sell now as their 8001 spring which is the Pac-1225 spring ?

And based on what type of engine you are building I would go with the aftermarket block if you can get one today ! If you cab do most of the work yourself on the 400 block then you might use that for some time. And if you do so you don’t need the steam holes for
Racing application with aluminum heads.
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Re: 406 SBC build... Which block would you choose?

Post by ChopperScott »

Thanks for the informative replies. I was asking about the stock block because my old man has had that stock 400 sitting in his garage for decades. He always wanted to do a 406 track build with it and never got around to it. I was already leaning towards a Dart SHP, as I have another recently completed 11:1 434 build with the SHP.
'73 Camaro Z/28 NETO/N
434 SBC 11:1, 1.294, 6.178 @ 108.87, 9.81 @ 134.93 (3060#, Naturally Aspirated, Sunoco Ultra 94)
Chopper Air Port 917-589-1278
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Re: 406 SBC build... Which block would you choose?

Post by ChopperScott »

BillK wrote: Wed Dec 01, 2021 3:32 pm Scott,
Take a look at this block I have in the classifieds:

viewtopic.php?f=31&t=63737
Thank you sir, but I'll pass.
'73 Camaro Z/28 NETO/N
434 SBC 11:1, 1.294, 6.178 @ 108.87, 9.81 @ 134.93 (3060#, Naturally Aspirated, Sunoco Ultra 94)
Chopper Air Port 917-589-1278
ChopperScott
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Re: 406 SBC build... Which block would you choose?

Post by ChopperScott »

Monza355 wrote: Thu Dec 02, 2021 9:04 am
And OP is the 8027 spring upgrade to what they sell now as their 8001 spring which is the Pac-1225 spring ?
Yes. 8027 is the upgrade number when ordering the heads. The individual number for the springs is #8001.
'73 Camaro Z/28 NETO/N
434 SBC 11:1, 1.294, 6.178 @ 108.87, 9.81 @ 134.93 (3060#, Naturally Aspirated, Sunoco Ultra 94)
Chopper Air Port 917-589-1278
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Re: 406 SBC build... Which block would you choose?

Post by miniv8 »

If you are not decided on the rotating assembly for a stock block, I would try to keep the bore oversize to the minimum. The pulling force of the threads in the deck will find their way to the bore, so.. keep the distance.
Here's a thread to keep in mind while torquing down the heads. viewtopic.php?t=40444

Consider filling the water jacket for added rigidity.

I had issues with oil starvation in the front, had great luck with plumbing a hose from the oil filter boss to the oil galley on top of the timing cover. Some blocks don't have it, so I made a fixture from one that did, and drilled a couple of blocks. Bearings ever since are not distinguishable from rear to front.

I gave up on running stock 400 blocks at my power level.
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Re: 406 SBC build... Which block would you choose?

Post by PackardV8 »

Agree with all the above. The OEM 400" block makes a wonderful, cost-effective street build and a fatally flawed race build.

RIP, Big Joe, who loved his 406"s.
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Re: 406 SBC build... Which block would you choose?

Post by ChopperScott »

Top end in question…
1EC35A44-CB4E-4DE4-8BE9-0513C0FF4B35.jpeg
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'73 Camaro Z/28 NETO/N
434 SBC 11:1, 1.294, 6.178 @ 108.87, 9.81 @ 134.93 (3060#, Naturally Aspirated, Sunoco Ultra 94)
Chopper Air Port 917-589-1278
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