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400sbc overheating issues??

but the power isn't the same... and a BB's inherent capability to produce a torque monster is very difficult to achieve in a SB...

a 400 requires a more radical build per cubic inch to equal a BB's power... thus becoming less street friendly, etc, etc....

500 hp and killer torque #'s are almost a nonfactor with a 496 or 502, whereas getting 500 hp 600 torque out of a 400 requires some extensive hotrodding...

i'd venture to guess the parts $ required to get a sb equal to BB output almost even it out on occasion... yes, BB's are more costly all things being equal, but build a 600hp out of either and the quality of components you need in the sb starts to even things out...

it all goes back to the hp to cube rule... a 500 putting out 500 hp is easy peezy.. a 500 putting out 750 is a 1.5 to 1 ratio and pretty hopped up.. 2 to 1 rad... now just apply those numbers to a SB...
 
Overheating in definitely NOT an isue in a properly built 400. I have a 406SBC in my suburban and tow heavily with it and it has never once overheated.

As for 400 vs 454, it all depends what you want to do. How much weight do you expect to tow? I'd say GCW of 15,000lbs would be no problem for my 400. above that you start to wish you had a little more power. Mine is just a mild build (8.6:1 C/R) with 4:10 gears...

Most I ever towed was 10,000lbs. That was a bit of a struggle. nothing terrible, but slowed down to 45-50mph on the hills... If I was doing that alot I'd go 454. On the other hand, a 3/4 ton Suburban shouldn't be towing 10,000lbs anyway...
 
I have looked everywhere, and cant figure out how to create a signature. where do I need to go?
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I think that you have to be a paid member for a sig, not sure. If you see a link at the top of the page named "user CP", click on that and find "edit signature" on the list on the left.

I ran a 400 for almost 200K, some damn hard highway miles with some offroad stuff thrown in, and it never overheated.............


Of course, it was a Ford, so maybe that is not as much help as it might be.........
 
as cheap as 454s are anymore I am using them up till they need rebuilds. Current one is a marshal engine rebuild with 90k on it. New cam, springs, timing chain and headers. Next one is a vortec 7.4 with 781 heads and a marine cam.
 
Well if you are not trying to build a 500-600 hp engine, the SBC400 has the advantages of neing cheaper to build, will rev up easier than a BBC.
But if you are looking for huge numbers then the cost will be up there with the BBC maybe even more, and reliability goes down since it's pushed beyond the block limitations.

nsxxtreme said:
What's the advantage given the power output is essentially the same?

Sure the BB has more power potential but also cost significantly more to build. Seems to me the smart thing to do is build the most power you can for the least amount of money.

If you have an unlimited wallet and max power is your objective then BB is probably your best bet.
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imiceman44 said:
Well if you are not trying to build a 500-600 hp engine, the SBC400 has the advantages of neing cheaper to build, will rev up easier than a BBC.
But if you are looking for huge numbers then the cost will be up there with the BBC maybe even more, and reliability goes down since it's pushed beyond the block limitations.
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This is what i meant by cheaper parts. Who needs a 500-600hp motor on a normal basis? Im saying a quality rebuild will run much less on a sbc, not some wild race motor.
 
your right, BB's are highly overrated, everyone should have a 400.... :rolleyes:

I stand by my original statement, I'll take a mild build BB anyday...
 
ryoken said:
your right, BB's are highly overrated, everyone should have a 400.... :rolleyes:

I stand by my original statement, I'll take a mild build BB anyday...
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Im not sayin they are over rated at all. BBCs are awesome and id love to have one but for my needs and most peoples needs they arent necessary, nor is that amount of power. Im in the 300s with hp and upper 300s with tq, thats fine with me and it cost me under $1500.
 
eh, more like 185 at the wheels... and if you had a BB in there you'd be extolling their virtues.... kinda funny coming from someone who's never owned a BB..
 
Ill have one someday, after ridin in daves rig i like em alot. For now this is a happy medium.
 
Ive neither owned a 400 or a 454, I could see this argument being 400sbc vs 396bbc, and if staying with stock displacement for the sake of argument, there might be more of a debate.

Adding more stroke will make more torque. Proven scientific fact. IMO we might as well be debating the 327 vs 350, or the 350 vs the 383.

The cost factor does fall into a grey area, SBC parts are relativley cheap everywhere. BBC not so much, but once again for our purposes, a BBC will make more torque, more easily than any SBC could.

Weight is yet another factor, does 150+ ft lbs more offset the added weight? depends on the app. IMO.

I dont think theres any real right answer for everyone. I would love both a 400 powered truck, and a BBC powered truck.
 
79rustyk10 said:
Ive neither owned a 400 or a 454, I could see this argument being 400sbc vs 396bbc, and if staying with stock displacement for the sake of argument, there might be more of a debate.

Adding more stroke will make more torque. Proven scientific fact. IMO we might as well be debating the 327 vs 350, or the 350 vs the 383.

The cost factor does fall into a grey area, SBC parts are relativley cheap everywhere. BBC not so much, but once again for our purposes, a BBC will make more torque, more easily than any SBC could.

Weight is yet another factor, does 150+ ft lbs more offset the added weight? depends on the app. IMO.

I dont think theres any real right answer for everyone. I would love both a 400 powered truck, and a BBC powered truck.
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Just dont forget even with equivalent cubes, no matter what way you slice the bread the small block still lives under its RPM requirement where as the big block is stump pull off idle.
 
Hmm, I'm now starting to wonder if my heads don't have steam holes. Seems like I remember them being 400 heads though....
 
rjfguitar said:
Hmm, I'm now starting to wonder if my heads don't have steam holes. Seems like I remember them being 400 heads though....
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That would be kinda funny if they didnt seeing your one of the only people that told me not to get a 400 because of the overheating issues.....:whistle:
 
does a 396bbc have more cooling fluid capacity than a 400sbc? That might be where the rumors/ problem arise. Dunno, so far my 406 is good, the 700r4 getting hot is more worrisome.
 
I have both, and to me the cost was nothing as I bought the truck with them and I bought them cheap.
Both are stock, and I would say yes the stock 454 has more torque than the 400sbc, but the 400 will rev up faster and higher, and yes the 454 is bigger in displacement too so it's not really a fair comparo.
Now once I have my 396 running in the 70 truck, I will be able to compare better.


79rustyk10 said:
Ive neither owned a 400 or a 454, I could see this argument being 400sbc vs 396bbc, and if staying with stock displacement for the sake of argument, there might be more of a debate.

Adding more stroke will make more torque. Proven scientific fact. IMO we might as well be debating the 327 vs 350, or the 350 vs the 383.

The cost factor does fall into a grey area, SBC parts are relativley cheap everywhere. BBC not so much, but once again for our purposes, a BBC will make more torque, more easily than any SBC could.

Weight is yet another factor, does 150+ ft lbs more offset the added weight? depends on the app. IMO.

I dont think theres any real right answer for everyone. I would love both a 400 powered truck, and a BBC powered truck.
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K85 Octane said:
does a 396bbc have more cooling fluid capacity than a 400sbc? That might be where the rumors/ problem arise. Dunno, so far my 406 is good, the 700r4 getting hot is more worrisome.
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Well yes it does have more, but it's also in where it goes, not just the volume.
The sbc 400 had some areas blocked because the walls would have been too thin if they kept them, that is where the 400sbc overheats when it does.
 
Deuling said:
That would be kinda funny if they didnt seeing your one of the only people that told me not to get a 400 because of the overheating issues.....:whistle:
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I'm almost positive that they are 400 heads, but I'm trying to recall thoughts from 10 years ago when I built my motor too.

I am not the only one that has had cooling issues, it's a known fact that 400's are harder to keep cool and have issues with cooling in general, among other issues with the mains cracking on the 4 bolt versions. There is a reason why GM quit making the 400's after only a few years of producing them. I tried to steer you in a different direction because it is just not worth the gamble when other options are so good, like a 383, or a 454. Doing it over again, I wouldn't bother with a 400, kind of wish I would have gone with a 454 myself.
 
By design, the siamesed cylinders tend to get hotter because of the lack of water jacket, that was because of the large bore and small block, in some cases it was overheating, so GM dropped it, but it wasn't that bad with most.
If I remember it right, that is where the exhaust ports are siamesed, and there is no room for water jackets to cool the block.
If you look at any 400SBC you will notice the color of the exhaust manifold in the section to be quite different because it's burning hotter.
Mine is, but it never overheats, it might burn an exhaust gasket though but with under 100k since 77, I don't think it had the chance to yet.
rjfguitar said:
I'm almost positive that they are 400 heads, but I'm trying to recall thoughts from 10 years ago when I built my motor too.

I am not the only one that has had cooling issues, it's a known fact that 400's are harder to keep cool and have issues with cooling in general, among other issues with the mains cracking on the 4 bolt versions. There is a reason why GM quit making the 400's after only a few years of producing them. I tried to steer you in a different direction because it is just not worth the gamble when other options are so good, like a 383, or a 454. Doing it over again, I wouldn't bother with a 400, kind of wish I would have gone with a 454 myself.
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