I found a guy in my town that says he has a "Chevy" 1970-1976 400 Small Block with the crank and rods. It's never been bored and the block is perfect.

What do you guys know about this engine, I thought only Pontiac made 400 small blocks? Is this one just as good? What can I stroke it too? Can you go TPI on it like the Pontiac 400's? How much is it worth?? This engine would be for a 1991 GTA with all the goodies like supercharger, 1000cfm TPI system, etc

Thanks.

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[This message has been edited by 92GTA (edited June 21, 2001).]

 

I've heard they have cooling problems, but correct me if I'm wrong. Yes, chevy did make 400 SB's

"Drive it like you stole it."

 

The SBC 400 has a 4.125" bore, 3.75" stroke. I couldn't tell you what its worth, but I can tell you its next to worthless if its been bored. They typically can't be bored out to more then +0.030 without cutting into the coolant passages. That doesn't give you much room for many rebuilds in its life. With a 4" crank and standard bore you can make it a 427.

Its still an SBC, so you can put any induction system on it that you could put on anything else. Heads and head gaskets have to have the steam holes drilled into them for the different cooling system though. You will want new heads for it too, these were truck engines originally and they all came with low compression smog heads.

If its in good shape I'd say go ahead and get it, they haven't made them for a few years now and they're not that common anymore, partly due to the limited number of rebuilds you can get out of them.

[This message has been edited by Apeiron (edited June 21, 2001).]

 

Right on, it's never been bored and a 427 sounds VERY sweet!

So, how much should I give this guy for it?

 

Good score on the block. If you do buy it, make sure to get it thoroughly cleaned at the machine shop. i hear most of the cooling problems come from the coolant passages being corroded as a result of being extremely high mileage truck motors. Also make sure to run the micrometers throught the bores. Some 400 blocks Ive seen barely had enough meat to go .030 over but others could easily go .060 plus with no problems. I wouldn't worry about the smog heads much either. Mill them down a bit to boost compression and you'll be set. With the big bore and long stroke, it'll be a real tiger. I would offer $200.

 

I know these engines are getting hard to come by nowadays. The local dirt track here by me has wasted most of the supply that was once located around these parts.

I have a 400SB that I have bought to go in a 1981 4-speed Trans Am of mine; it is a 1973 model engine and has been treated to a "stock" rebuild with good quality parts. My local shop disassembled it enough to ensure that the work was done well, and correctly. I bought the entire engine already rebuilt and with an Edelbrock Performer intake for $450.

So I'd say $200 is a good offer for that one you're looking at.

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Thanks, I'll start at $150 then and see what he says.

 

The chevy 400 sbc came in trucks

 

Ok, I called the guy and it is a 2 bolt thank god BUT the guy will only sell it with the crank and rods and he wants $300!!! I've seen it and it is in like perfect condition and it totally factory still.

Is 300 too much??

 

I've seen WAY more 400s come out of cars than trucks.

The 400 was available in Caprices, Impalas, Chevelles, Monte Carlos as well as trucks.

A good portion of the Impala station wagons from 1970 to 1976 had 400s.

In a mild street engine, the early 4-bolt main block will not be a problem.
jms

 

A two bolt SBC 400 is actually stronger than the four bolt version. There is more meat. Not sure if you convert to a four bolt if it weakens it or you should leave it as a two bolt.

Also, building a 427 would be nice, but difficult. Even more difficult if you want it to be as reliable as your GTA's engine. The drivetrain geometery gets out of whack when you stroke a 400. The ratio between bore and stroke... You probably won't be able to rev it too high. 5500 max?

You can find a lot of guys that know a lot about SBC 400s, so do your homework. I was going to put a sbc 400 into my 64 nova, but sold the novas to get my B4C.

Look for the three block(drain)plugs on the side to quickly determine if it's a 400.

later
john

 

Not all 400s had three freeze plugs on the side. The early years had three. The mid-year versions had just two but had a raised area for a third. The latest versions had just two and have fooled more than one tech inspector!

As far as the 4-bolt versus two-bolt, if the price is fair, don't turn away from the 4-bolt. It will be fine on a mild street engine. I've run both.
jms

 

The cooling problems stem from the fact that because of the bore size; the water jackets are eliminated between the cylinders. (Water jackets running along either side of each bank of cylinders but not between them)

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ALL 400s did have the humps around the cylinders on the outside of the block. if you look closely or run your hand down the side of the block you can feel them.

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