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400 sbc???? (All assembled)

Idk i know him and he is a pretty cool dude, he told me when i posted that link up about that crate 350 that he could build me one for same price, but i would know i was getting a good motor. Hes not some random dude, so that helps. And I dont care anything is better than this 305 that struggles to drive up small hills and has a nasty low end knock and 15 psi oil pressure at 2000 rpms.... and pretty much 0 at idle.

And by small hills i mean on the road, havnt taken it offroad yet lol.
 
Ok, here is the scoop on 400's.

1. The more it's overbored, the worse the overheating issue is. I don't know why exactly, but multiple people have told me this. They say .030 is as big as you want to go before the walls start getting too thin.

2. Like mentioned, externally balanced. No big deal, just get correct externally balanced parts. Non issue.

3. The heads, got to have steam holes and I would recommend going with better heads. No small block responds better to a bigger/better head than a 400, simply because it's trying to breath 400ci worth of air through the same head a 305 could potentially have from the factory.

4. You want a 2 bolt main block. 4 bolt main blocks have a lot of problems with cracks around the mains for some reason.

I would NOT buy a 400 over again myself, my 406 has been a PITA to keep cool. I have a 4 core BBC radiator and Flex a lite dual fans (those truck fan systems) and I have a hard time keeping mine under *200 in cool weather. In the summer it runs 210-220 no problem, with the A/C on and the engine idling on a warm summer day, the temp steadily climbs uncontrollably until I get it moving again.

Bottom line IMHO, 400's are not worth the trouble they come with. It's tough to keep them cool and you could just build a 383ci and have the same power output and run 180* all day long. 400's are just not a very good designed motor and I hate to say that since I'm stuck with one myself.
 
I think i will try it and see what happens, i will look into a better cooling system and see how it goes, if its not what i want im sure i can get my money back, and the guy im getting it from could get me something else. If its nice and freshly built hopefully it works better than a used one. I dont do a great deal of idling, and mostly 55mph driving.
 
Deuling said:
I think i will try it and see what happens, i will look into a better cooling system and see how it goes, if its not what i want im sure i can get my money back, and the guy im getting it from could get me something else. If its nice and freshly built hopefully it works better than a used one. I dont do a great deal of idling, and mostly 55mph driving.
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I completely rebuilt my 400 myself, and started with a fresh engine also. It doesn't make a difference. I also don't do much idling, and was mostly referring to those long stop lights. Another thing I forgot to mention, watch out on your compression with a 400. I have to run 91octane and mine is only 9.2:1. The problem is they run higher cylinder temps than a 350, because of the Siamese cylinders, therefore pinging happens easier.

When I was 17 and building this motor, I thought it would be the best thing since sliced bread, not to mention how cool I thought it would be to have a 400+ci SBC. My opinion is drastically different these days. It's just simply a poorly designed engine.:frown1: Who knows though, they could be very inconsistent and maybe I have a "hotter" one than average.
 
rjfguitar said:
Ok, here is the scoop on 400's.

1. The more it's overbored, the worse the overheating issue is. I don't know why exactly, but multiple people have told me this. They say .030 is as big as you want to go before the walls start getting too thin.

2. Like mentioned, externally balanced. No big deal, just get correct externally balanced parts. Non issue.

3. The heads, got to have steam holes and I would recommend going with better heads. No small block responds better to a bigger/better head than a 400, simply because it's trying to breath 400ci worth of air through the same head a 305 could potentially have from the factory.

4. You want a 2 bolt main block. 4 bolt main blocks have a lot of problems with cracks around the mains for some reason.

I would NOT buy a 400 over again myself, my 406 has been a PITA to keep cool. I have a 4 core BBC radiator and Flex a lite dual fans (those truck fan systems) and I have a hard time keeping mine under *200 in cool weather. In the summer it runs 210-220 no problem, with the A/C on and the engine idling on a warm summer day, the temp steadily climbs uncontrollably until I get it moving again.

Bottom line IMHO, 400's are not worth the trouble they come with. It's tough to keep them cool and you could just build a 383ci and have the same power output and run 180* all day long. 400's are just not a very good designed motor and I hate to say that since I'm stuck with one myself.
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It's not a bad design. It's the biggest GM can go with the small block. The center holes are touching ie: lack of water passage. If your not sure why things are acting like they are, don't give out uninformed advice. Alot of different engines when taxed like your have a hard time cooling themselves.
 
Yah i have been reading different forums about them and it seems like some do and some dont, some fill the the block around the middle cylinders and others dont, Idk i will have to see what happens, I mean $900 sounds like a darn good deal to me and if it over heats alot off the bat then i will take it out before any real damage can occur.
Their is something mentioned about a steam hole that some guys say must be drilled that helps alot, i dont really understand what they mean by that though lol.

Hopefully me running stock tires and setup will help put less stress on the motor and keep it cooler idk.

Hopefully it for once will just go my way and not be stupid lol, i could really use a good deal right about now in my life.
 
Deuling said:
Yah i have been reading different forums about them and it seems like some do and some dont, some fill the the block around the middle cylinders and others dont, Idk i will have to see what happens, I mean $900 sounds like a darn good deal to me and if it over heats alot off the bat then i will take it out before any real damage can occur.
Their is something mentioned about a steam hole that some guys say must be drilled that helps alot, i dont really understand what they mean by that though lol.

Hopefully it for once will just go my way and not be stupid lol, i could really use a good deal right about now in my life.
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There is no "fill" between the cylinders. They are cast that way.
 
my old boss has a 427cid 351 w stroker motor in his 68 mustang.

had new rad and fan kit. couldnt keep it cool.

for xmas 1 year we got him a becool aluminum rad and twin fan kit.

he took it out after install. he come back 20 min later and no fans on. we were goin crazy. but he said temp 190-195* and never went over 200* and he has never ever been able to flog on it like that since day one .

found the 1 wire installed wrong and fixed fans problem. watched the temp drop 30-40* in under 1 min sitting there.

that was the best money we ever spent on a product and got as advertised results.

this guy has the hook up on becool stuff. if you dont see what you want ask him. http://shop.ebay.com/terry_rosebush_motorsports/m.html?_nkw=&_armrs=1&_from=&_ipg=25
 
Merv said:
The block fill. Fills the entire water passage. makes the block stronger in race specific engines. Has nothing to do with the cylinder design of a 400.
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I was talking about for cooling, since people are saying they are hard to keep cool.
 
If he is building this thing stock (idk i sent him an email asking what exactly is going in it) what do you guys think the hp trq specs will be???
 
400 ROCKS great torque very buildable.
This Very truck right here has a 400 in it and it is bored out to a 406 is BAD ASSSSS:bow::bow: Ive seen it on everything From the Dragstrip to the ICE Lakes. Its a good way to go PLeanty of Power and More good luck man

TnS1 (604x453).jpg

TnS (604x453).jpg

Tom n Snake (604x453).jpg
 
Deuling said:
ahh ok its a 400 40 over, so 408. He told me 900 fully built with rebuilt stock heads and no intake. Its at the machine shop at the moment.
6 weeks prolly omg im so excited!!! haha :thumb:
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I don't think I am going to be able to deter you from getting this engine since everything anyone said here didn't change your mind, but:
40 over on a 400sbc is not good for a street driven truck.
I know lots of racers do it but they don't use the engine for more than a few runs down a strip.
I have a stock 400 in my blazer and still has under 90k original miles, and I can say I love the power, hate the fuel consumption, but never had an issue with heat.
Again, it's still stock, so it works good.
I do have another engine that is 30 over and I will be cleaning it up and running it in a boat, but will not run it in a truck.
:dunno:
 
I can get you in touch with the owner of this Rig. If youd like and he will tell you everything you ever wanted to know about the 400sb let me know
 
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