Where to find 400 Chevy Small block?

[77'/85'scottspecial]

I am going to build up a 400 small block for my truck. I think it would just be easier to find a vehicle that I can get the whole motor from. What vehicles/years were 400's used? Thanks

[b454rat]

I know 73-80 will have them, but cars came with them too. I'm sure 67072 will have some too.

[SOFA-KING BIG]

I've heard that the 400 SB was always the less desireable small block to rebuild.
That's because the cylinder walls are to thin.
And a block core that isn't junk already or doesn't need to be rebored is a hard find.
Sorry, But that's just my .02
Best wishes &
Good Luck with your project!

[77'/85'scottspecial]

I have seen some nice build ups. I was hoping around 400hp and around 500 ft. lbs. They bore them .030 over, variety of cams, use vortec heads, bigger carb and headers. Here is an example but I'm not going this far with mine.

Here

[b454rat]

Not to sound like an ass, but if you are a car guy or know any car guys, you will know that the 400 is the MOST desirable SBC. Any mods you to do another motor, will work on a 400, and with better results. I had quite a few 400s, all of them were truly awesome motors, even one with over 200k on it, and all stock lower end. A friend of mine used to build motors for roundy-rounders and had a 750 horse 434, and used a GM block, not aftermarket. Only thing that killed it was ran low on oil, and got hot, and it cracked the crank, didn't nothing to the block. In fact, my buddy Jeremy has the block, and he had about 500 horse out of it. If you build the motor right, you won't have any probs at all. About the only prob I had was with the valve springs, too big a cam and stock springs, kept breaking the rocker arms. If you can get one, go for it. Make sure that the bore is good, you can only go .040 over, any more you will have cooling issues. I had one .060 over, and constantly ran hot. Use regular 350 (5.7") rods, mild cam, even stock heads, and it will put you in the seat.

[SOFA-KING BIG]

1st I'm a Truck guy, if I was a car guy I would post on a different website.
And you just nailed it... you can not bore more than .40 over and good luck with that!
Other than that it's a great motor.
So If there is any real scores or lip in the cylinder walls that you'll discover after you get your junkyard core home.
Then there is your .30- .40 over.
Now I never said this SB was bad.
Just that I would prefer one with a different bore and Why not, same power levels, more common availibility, and less problems.

Nobody should have to be an ass.(I edited for better wording)

And the block in the link that he's using as an example is a special custom built aluminum block.
and that's a totally fawkin different thing!
$ I'VE GOT CLUES FOR SALE $
Does anybody need to get one?

[SOFA-KING BIG]

PS.
I believe the most desireable stock SB is a 350 4-bolt Main marked .010 (The one with the highest tin and nickel content)
(Just off the top of my head I don't have the specific block #'s)
But you can ask any local race track engine builder....
Just my .02
Take it or leave it.

[77'/85'scottspecial]

I know that block is different and don't think I will have anything near that except that it is a 400. Since those motors are powerful stock, It is more than I will need after building them up a little. So I will begin my search and let you know what I find, Thanks.

[b454rat]

Why should I feel like an ass?? I would rather build a 400 than any other small block. Everything that you do to a 350, will work in a 400, and will get more power and torque out of it. Thats why alot of people look for these motors. I am a car and truck guy, have had 400s in both cars and trucks. Not trying to turn this into a pissin' match. As long as the bore is good, like Sofa said, then you will be good to go. It isn't really that expensive to build a motor, 400 being no different. If the block is good and can be cleaned up with .030 over, get a set of 350 rods, 882 or 993 heads, mild cam, intake and headers and you will have the power your looking for.

[odgreen]

I'd love to find a good 400 sbc here, do not bore them over .30 no matter who tells you different, make sure you have the steam holes in the heads if they aren't 400 heads and they will not over heat anymore than any other sbc and make great power. Do not get a 4 bolt main, the 2 bolt is stronger.

[s10bogger]

Most desirable small block setup is a 350 with a 400 crank (ie:383 stroker) for making high HP numbers or a build to the tits 355. Hell I've got a buddy whose dad has a 800 HP (on the dyno) 355 that will run 9's at the track in a Chevelle. The 400 is a wicked torque motor (cuz of the longer stroke and the 5.650 rods). The Ideal build up is the 5.7" rod or a 6.0" (for a locomotive motor). The 400's do have cooling problems cuz the water jackets are not as well designed as other SBC's. Go .30 over run a mild cam (ie. 270H comp cam) with the stock heads (ported and polished of corse) and you should be fine. The 400 is not a RPM motor (unless you use the 6.0 rod) but that would be way out of your price range. The 400 was never a high performance motor from GM and was available in FS vans and cars. The older the block the better and there are a few rare 4 bolt 400's to be had. I've got a bunch of info on casting numbers and what to look for (I've just gotta find it first or the link to the site).
From personal experience I'd try and leave the motor as stock as possible for off roading, if the motor is going in a mud truck or something that will always be close to a trailer then I'd build a motor. I've got a 355 sitting in the garage right now that was going to go in my rig for next year but opted out of that cuz I didn't trust the motor as much as the almost stock one that I've got now
Just my .02

[odgreen]

The 400's do have cooling problems cuz the water jackets are not as well designed as other SBC's

This is a myth, there are plenty of guys dragging 400's in vettes and f-bodies pushing in excess of 500HP and not one single overheating issue. Like i said don't go over .30, make sure the heads have steam holes (this is where it started by people not drilling the heads properly) and the right size radiator for your HP level and it will run as well as any other sbc and will surpass a 383 as well. 6.0 rods aren't worth the trouble

[odgreen]

Most desirable small block setup is a 350 with a 400 crank

You can actually end up spending more building a 383. By the time you have the 350 bored .30 and get a good crank for it you've already spent a good deal, you can't put a 400 crank into a 350 unless you turn down the journals to 2.45. Stock 400 crank can easily handle 400+ HP. Caddy motors have a high nickle content as well as the rocket blocks. 383's are also known for high torque like a 400 just smaller

[s10bogger]

Spend more=built right. I've seen many people in the past (personal experence) say that they can build power cheap, yes you can...but how long will it last (goes back to what I said in my other post) and the motor will only last the summer if that others that have spent the money the first time and built it right are still running the same short block. I spend lots of time at drag strips in the summer (my 1st passion) and 1 out of 40 cars might have a 400 small block in it. Most are 355's and 383's if they are small blocks. Another buddy has a 383 in a 81 z28, drives the car around all day (this one had close to 650HP last year and will be close to 900 HP this summer without he bottle) he beats on this thing like there is no tomorrow and nothing has ever let go.
I was planning on building a 406 a few years ago but opted out cuz after talking to many people that ran them (most ran them in either s-10 or vega's) said that they had heating problems and the motors did not like high RPM's (shifting at 5500) and these motors were putting out 500 HP.

[61_chevy_4x4]

Originally posted by s10bogger
The older the block the better and there are a few rare 4 bolt 400's to be had.

wrong! the 2 bolts are more desirable because of the thicker webbing around the block and the fact that its easier to go to splayed main caps.

[odgreen]

77'/85'scottspecial, get yourself a 400, bore it .30 and you now have a very reliable 406 torque monster. Stock crank can take alot of abuse if it's in good shape, assume everything is in good shape and it hasn't been bored already. Yes as i and 61_chevy_4x4 said pass if it's a 4 bolt but you'll have to drop the pan to find out. I'll say it again if you use non-400 heads drill out holes for the steam holes, this is the major reason a 400 overheats leaving people to claim they suck because they heard from somebody....many many people have run these motors without any problems what so ever, plenty have assembled them wrong and tell everyone to avoid them, so it's hard to know what you'll find till you take it all apart and check it.

[panty dropper]

I have to agree with the fans, I have had the best luck with 400's I have had three chevys with 400's in them all bone stock and they all went very well and never heated up, and if you aren't going to get real crazy with it either block should work, My 78 chevy is on 42's with 4.11 gears and burns out on dry pavement with a locker and a stock 400. The best place to look is in 73-78 chevy pickups and 73-78 chevy fullsize cars (impala, caprice, wagon) But like the other guys said if you build it right it will waste other similar size engines, A beefed up 350 in a similar truck with better gearing and smaller tires still cant keep up with my truck so dont listen to your friends when they dog that engine (every one of mine has talked bad about me leaving a 400 in my truck) they all think I need a 350, but keep searching and let them have their precious 350's just like everybody else out there. My two other trucks with 350's in them have both left me stranded the other three havent, might be good luck, might be the engines either way I am a fan of not walking home. and the 400.

[shagg]

WOW !! well i`ve ran 400sb for years for a truck engine their A1 gobs of tq easier on gas than my bb ,, lighter , but in my younger days of first running 400`s they would over heat crack the heads and somtimes even the blocks high rpms loosened the bottom ends fast!!! then i asked my uncle who runs late model dirt track how does he hold his together and not over heat , he laughed and said come by the shop, first thing he told me ditch the 400 heads run 350 just redrill the steam ports, find a 2 bolt for street if i wanted to get serious add splayed 4 bolt caps , but never run the fact 4 bolt block , there is a way to tell the 4 bolt mains will have freeze plug in the middle of the block 2`s dont , yeah yeah i know but just check a few, the reason for cracking is the higher content on nickel in the 400 blocks and heads , then run 5.7 or 6.0 rods which ever i could afford for a better ratio , run good parts not cheapies , have the crank cross drilled and a good oil pump which holds enough oil volume but not too high of pressure, cause that would cause bottom end failure too , well i didnt have the money for all that so i done the head swap on my overheating 400 , cured it , so later i tried all of his tips and had a higher revvin 400 that held and didnt over heat and ive ran 60 bore with no prob`s but it was in a full size not a s10 or vega monza type, i know i strayed from your question its simple most 2 bolt main engines were used in impala caprice type land yachts oh one more quick way to tell a 400 and yeah i know you heard the flywheel/ front bal. but those can be switched for a guy looking for a quick sell , check the block the 400 is the only block with the sides that are swelled out to hold extra coolant around the saimeesed cylinders hopes that helps and sorry for the length and check the inside under the intake cyl walls also , and if its been ran hard look close at the mains they will crack away from the block later shagg

[tony 3/4 ton xj]

You can bore a 400 .60 over. I know a dude that has a 400 and it is .60 over its a hoss. No overheating probs. Bowtie heads, ported/polished, victor intake,roller cam.(race motor though) Put the bottle to it and damn.

[odgreen]

Well when the late lingenfelter and Yunick and i can go on tell you to not go over .30 for the 400 i think i'd follow there advise and not because of a friend that did it once but thats just me

[HeyBeerMan]

Hate to break it to all you bench racers, but the most desireable SBC's are "what ever the dude who is building it wants, and is willing to pay for."

Thats the cool thing about them. All the choices and combinations. I myself chose a 434 for my Jeep, but to each their own.


If your having cooling issues with a 400, it means you have something f_cked. Fix your problem and it will cool fine, don't blame it on the 400.



Beerman.

[77'/85'scottspecial]

I have heard from everyone about the steam holes. If I do use other heads where do I drill them? Thanks

[odgreen]

Just use a 400 gasket as a guide

[JeepinDoug]

SBC 400 is a siamesed bore block which means the cylinders are sistered together, no water jacket running between them. The 400 block is also externally balanced and has a special harmonic balancer, compared to a 350.
There problem you may have with boring a 400 is deck warping over .030", it really all depends on the block quality. I have a 350 at .040" over and that's the max for it after checking but some other blocks could bore good.
A seasoned block will stand up to more bore than a non-seasoned.
The main thing that hurts running a 400 is the parts cost a little more, cooling isn't much of an issue as long as you're not running 13.5-1 compression. Shit, they ran this engine in Surburbans, if all that weight doesn't hurt them I don't know what will.

[86k30]

theres a prime 2wd 3/4 ton on ebay right now with a running 400 for something like 500.00 . buy it and then reply to my post for a cheap or FREE ff srw 14 bolt . I'll take it off your hands for no charge. Buy the way ' I just sold my last 400 block to some crazy roundy round guy for 500.00 . It was just a bare block with 4 bolt caps and it was standard bore. For those who think im BSing, I'll scan the bills for you!!!! That ought to tell you how difficult they are to find!