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Author Topic:   NEW 400 owner
Oldsmobile13
Dirt Full Roller

Total posts: 66
posted July 26, 2001 02:15 PM
I just bought a 400 sbc and i need to know what the best stock heads and pistons would be for this, plus anything else i should know before i start to build it. I have a set of 461s if these would be good it would sure save me some money. How important is it to have this engine balanced?

Racer4
Dirt Forum Racer

Total posts: 93
posted July 26, 2001 02:33 PM
461's should work great! Don't forget to drill the steam holes! their small chambers should give the 400 a great bump in compression, especially if you use the thin steel shim head gaskets and have the block zero decked while you get it balanced. Shoot you could even angle mill the 461's if their not already, easily achieving 12 to 1 compression with flatop claimers from Kieth Black, use some rebuilt 5.7 rods with ARP rod bolts, they have claimer pistons to fit this combo, cheap horsepower for You to say the least! Get it all balanced, just don't over-rev the cast crank and two bolt main caps. You will need to make sure to have the proper flywheel and harmonic balancer. Good Luck!!

race8k
Dirt Full Roller

Total posts: 42
posted July 26, 2001 06:11 PM
I think if your cut the deck to 0 and use a thin steel gasket of about .016 you will likely make contact with the heads.I would say .038 deck would be a min. to keep it safe.Don't forget to check piston to valve clearence.Most guys don't drill steam holes on race motors but you have to on daily drivers.I would go to 5.7 rods to get a better rod angle. You will break the 5.565 rods if you turn the engine at all.

Oldsmobile13
Dirt Full Roller

Total posts: 66
posted July 26, 2001 06:49 PM
Will it run hotter without the steam holes, and what exactly do they do for the 400?
Will rods out of a 350 work if i get different pistons?

[This message has been edited by Oldsmobile13 (edited July 26, 2001).]

Oldsmobile13
Dirt Full Roller

Total posts: 66
posted July 30, 2001 05:01 PM
Just today somebody told me this 400 would overheat at the track, is this true if i dont have an alluminum rad.

millerlt3
Dirt Roller

Total posts: 22
posted August 02, 2001 03:05 PM
I know a few people who run the 400's and they dont seem to have a problem with overheating. One of my buddies run a 400 sbc and his engine builder plugs off the steam ports in the heads because he says they crack from the chamber to the steam ports. Has anyone else ever heard of this?

CNC DOC
Dirt Roller

Total posts: 20
posted August 02, 2001 08:01 PM
It's common for them to crack from steam hole to the head bolt hole just above the steam hole.

Oldsmobile13
Dirt Full Roller

Total posts: 66
posted August 03, 2001 11:32 AM
What should i do to keep it from cracking?

Racer4
Dirt Forum Racer

Total posts: 93
posted August 03, 2001 11:43 AM
What heads are you guy's referring too? He has 461's these are heavy casting's and are not prone to cracking. You need to give him the reason he should not run steam holes in his 400 with these heads, personally I'd like you to explain to me how the engine is supposed to cool with the smaller water jacket's of the 400 without steam holes. I don't think he is running alcohol, so he has to stay cool running gasoline!

Oldsmobile13
Dirt Full Roller

Total posts: 66
posted August 03, 2001 07:07 PM
Yes i am running gasoline and a 2bl, i have been running 355s with the 461 heads and have had no serious problems with overheating but i am not so familiar with the 400 engines. Would boring the 400 hurt anything as far as keeping it cool?

CNC DOC
Dirt Roller

Total posts: 20
posted August 03, 2001 09:23 PM
Sorry, I didn't pay enough attention. I was refering to the block, not the heads.

millerlt3
Dirt Roller

Total posts: 22
posted August 08, 2001 09:46 AM
I was not saying he should plug them, I was just asking if anyone had ever heard of anyone else pluging them, because until my buddy told me about his and I had never heard of it.

Red Dog
Dirt Roller

Total posts: 7
posted August 08, 2001 05:43 PM
95% of the 400's we build have the steam holes (in the block) plugged. The other 5% don't wanna spend the extra few bucks.
As far as plugging the steam holes in the heads - very seldom do you find a 400 head that's not already cracked across the center exhaust seats. Usually use a 350 casting.

Oldsmobile13
Dirt Full Roller

Total posts: 66
posted August 09, 2001 04:19 PM
Why would you want to plug these steam holes, isnt that all that cools the cylinder walls?

Donnie Ross
Dirt Newbie

Total posts: 3
posted August 17, 2001 09:00 PM
the steam holes are not needed if the engine
will be primarily run above 3000 rpm as the extra pump flow will purge steam pockets,this
is according to the chevrolet power manual,
never drilled the holes in my 292's no probs in 4 years.however I use one to one pulleys
not underdriven may make a diff.

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