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Any thoughts on the SBC 400 block??


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Guest Anonymous

There is a guy in my area selling a rebuilt 379 short block. It has 5.7" PM rods from the LT1, Hyperutectic (SP??) flat top pistons, a stock 350 crank, and the 400 block which is bored 40 over. Everything is new and assembled. It yields 379 ci which would be super for making the HP and torque I'm looking for. What are the thoughts on this setup? I have heard both good and bad about the 400 block without justification either way. If this is a good setup, how much should I be offering him for it? He built the engine himself and he said he has built many SBC's from the ground up...so if it is true than the motor will be good.

 

SpencZ

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Why is he selling it? Does he build engines for himself or others? If others I would try to find out some names and ask how their engines run. Does he have some sort of written guarantee? As for the 400 block I've also heard good and bad, so I'm not sure.

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Well I can't tell you what to ask for this package. The big issue as you already know is the siamese bore. I think the fact that the block was discontinued and isn't found much in the aftermarket would be enough for me personally to stay away from it.

 

Now, that said, I know of several guys running 400 blocks in different configurations and doing well. Jim Biondo is running one in his car and from what I read, it is a real screamer. So I guess I'd try to get it for a steal (Find out what it is worth and then "reasonably" low ball him) if his build reputation checks out!

 

Mike

 

------------------

 

"I will not be a spectator in the sport of life!"

mjk

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Guest Anonymous

I'm running a 400 SBC with a Stroker kit, making a total of 420ci. I have not had any cooling problems and it's just a beast in my 240. Like they say..if a little is good, more must be better.

Al Peterson

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Some folks give the 400 a bad rap because it has "siamese" bores so it's a bit difficult to keep the cylinders round as the engine goes through it's heat cycle. That does not make it a bad engine for the street - just don't plan on running the Daytona 500. Let's face it, there where thousands of these engines that people drove every day for thousands of miles without any problems.

 

However, I think you will find that the biggest reason for the bad rap is that people don't know how to build one. Because of the siamese bores there are two "steam" holes between each cylinder. If you change heads, then you have to drill these holes in the heads and make sure they match (or drill holes to match) in the head gaskets. If you don't then steam gets trapped up at the top of the bore and, as we all know, steam does not cool. Now you have a hot spot, which tends to cause pre-ignition (pinging/knocking) which is bad. If it continues to knock then it will probably come apart!

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