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SBC 400


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Thought I would throw this out....I found a SBC 400 never bored short block for $100. Its an old Mexican guy that wants to sell it. He said the block is good and he will guarentee it. Question is what do I do initially to freshen it up? Get it tanked amd magnafluxed? Also should I bore out the steam holes? Finally have new freeze plugs installed I assume. I want it to put on my engine stand until Im ready to build it. Should I have the crank turned 10 thousandths as well for the hell of it? Also how much should I have it bored? Is 30 over a good start? Finally should I have all the parts balanced? I dont know all involved between internal and external balancing. which one is best?

 

Question for Grumpy! I want to put my AFR 190s on this engine possibly. My cam is the Comp cams XR282, 520/510. Im running the Holley750DP AFR match ported intake and will run the 1 5/8 block huggers until I can get the Sanderson 1 3/4 Long tubes. I will use my current 5.7 eagle rods full floaters. I will go with some flat top hypers as well and total seal rings. Can anyone estimate the HP in Desk Top dyno? I need to know if my HP/TQ will be better using the AFR190 heads as compared to the 350. My last dyno said 379.4 RWHP so it should be close to 450 off the 350 crank. AFRs build showed that so its close. How will the 406 do in comparison with the same add ons above? I dont want to spend a ton more on new stuff....

 

ZFAN, if this works out, I may go 406 vice 383....$100 is $100...I hope the block is intact.

 

Thanks in advance......

 

Terry

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First of all, jump all over the 400 sbc. 100 bucks is great, is it a 4 bolt? I would disassemble the short block and have it checked out. Have it vatted, new freeze plugs, bore 30 over and decked.

 

You could use the stock crank and buy some H-beam rods on ebay for 320 bucks and some forged pistons as well. If you have the money buy a Scat or Eagle steel or forged crank.

 

If you went with a forged rotating assembly and had all the above block work done it would probably set you back 2k. Just guessing.

 

The AFR 190 heads are a bit small for the 400 sbc but it would be an absolute torque monster :shock: with your heads, cam, intake, carburator and headers on a 10 to 10.5 to 1 400 sbc I would guess close to 500hp/500+tq :shock:

 

Better stiffen up the car :D Oh, and keep a clean pair of shorts handy :D

 

Mike

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Lol! Roger that! Im already freaking out when I get on it now...I havent gotten used to it. Once it hits third gear its like that Racer X feeling on Speed racer... :D Ive never driven anything faster than 13.7 down the strip so one step at a time I guess... thanks for the input..

 

Terry

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Guest Fastest240z

Yes, I would but the 400. Regardless of the parts you put in the motor you must have good machine work done. The longgevity of the engine will be determined by the quality of the machine work. Get good pistons and nice rods and don't worry too much about the crank. As long as the crank is in good shape balance the whole assembly and it should last through anything you will throw at it.

 

How many times do you hear of people braking cranks? Pistons get holes in them, rings brake and rods bend, but cranks ussally are not the source of failures.

 

The prep work to the block should include a line hone ,pluging the steam holes and placing retrictors in the water hole on the deck surface. This aids in sealing of the head gasket and take nothing away from cooling as long as you have a good cooloing system.

 

Mark

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Sounds like FUN :-D

Yea! two types of 400 SBC 1970 to 72 they were 4 bolt then 1973-80 they were two bolt main bearing caps.

Both have same 4.125 bore 3.75 stroke 2.65 main journal dia. 2.10 rod journal dia. I get excited just thinking about those 400's :b_hand:

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You can tell the 2 bolt block from the 4 bolt by the number of freeze plugs, the 4 bolt block has three on each side, the 2 bolt has 2, just like the 350 block. The four bolt is more desirable, but rare, and really, unless you are building a very-high output motor, the 2 bolt block is a very good choice. Good Luck. Those 400's will surprise a lot of people, let everyone think it's a 350, and leave them wondering how your car can walk right away from them.

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Badriver

I thought they all had three freeze plugs on either side. How would a person be sure he has a later two bolt version 400sbc by identifying marks? Wonder what # and where located identify 400 sbc from the outside?

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I asking about identifying signs because I will be looking at a 400 ci engine and wanted to make real sure it was a chevy doesn't matter to me if a 2 or 4 bolt main) 400 sbc and not possibly a pontiac or even just a 350 for that matter.

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I thought and believe I read in books that the freeze plugs determine the number of bolts on 400 mains also. But a machinist told me that is not true. He said he had four blocks and one three was 4 other a 2 sooo.

 

Maybe the freeze plugs will id the better blocks?

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Just because you add displacement doesn't mean you'll again HP. There's no doubt that you'll gain torque and we know that "Torque is King". My buddy has a built 400 SBC in his 240 w/ ported heads and such. It's only putting out 300HP but nearly 500 ft lbs torque. Having a stroker is great for a driver, as the torque makes the car quick and very driveable. The only downside is that the 400 will redline at 5500 rpm, so the right rear end ratio is needed to take full advantage of the torque. HP is rpm related and the 400s don't rev all that quickly, but with that torque and a 3.36 rear diff, it doesn't need to! :-D Just my 23 cents.

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