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400 or 440 build

Cranky said:
Somebody wrote up about using a low compression 440 piston in a 400 block. Anyways I also like big bore Short Stroke engines. And piston speed is also slower and the Short Stroke engine so you can turn more rpm with it and not worry about Ring flutter but I think today's rings are much better anyways. Not sure about cylinder walls being thicker but they are shorter which makes them more rigid. Also large bores help unshroud the valves more....
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Im in the middle of doing this right now with a 77 440. Trying to choose a cam for stock pistons, -.040 below stock deck height and Eddy 75cc heads.
 
The car is a 71 Charger, has 4.10 gears, hydroboost brakes so I'm not worried about vacuum and plan to street/ strip use.
 
The 318 is built and is a high reving engine and has been alot of fun but doesn't have the bb torque. The other thought was to turbo charge the 318.
 
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drhill said:
The car is a 71 Charger, has 4.10 gears, hydroboost brakes so I'm not worried about vacuum and plan to street/ strip use.
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Great minds think alike! Nice
 
I would send both blocks to the machine shop and have sonic checked then you can make a decision from their. My vote is 400 block
 
drhill said:
Which would you build a 400 or 440. I have both and was wondering which would be best. I have a 383 steel crank for the 400. Both engines are 1974 castings. I was thinking of using Trickflow top end.
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I did a 512 stroker, used a 400 block, 440 Source rotating assembly, 240 trick flow heads with matching Trick Flow intake, Hughes solid roller, 683 lift 254 duration and had Jessie Bigsnell build a carb for me. Can't go wrong with the 400, stronger block.
 
Terry Host said:
I did a 512 stroker, used a 400 block, 440 Source rotating assembly, 240 trick flow heads with matching Trick Flow intake, Hughes solid roller, 683 lift 254 duration and had Jessie Bigsnell build a carb for me. Can't go wrong with the 400, stronger block.
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I didn't realize how fragile a 440 block is until I started reading these posts. It is hard to believe that an additional 3/4" of deck height ruined the 383 block. I guess I should be careful when driving my 1967 R/T.
 
Dave6T4 said:
I didn't realize how fragile a 440 block is until I started reading these posts. It is hard to believe that an additional 3/4" of deck height ruined the 383 block. I guess I should be careful when driving my 1967 R/T.
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The 440 isn't exactly a weak knee weakling.....it's just the 400 block is a bit stronger and that's always a good thing.
 
This thread certainly devolved into a mess of differing advice.... If the OP wasn’t confused to begin with, he must be now.

As far as cost to build a 451 (which I will again argue is the best option using the parts he has), all you’re talking about is the cost to turn a crank in a lathe. It’s probably $250 or less, and if that’s too much, this whole conversation is moot. From there, the same parts in a 451 vs 446: the 451 will rev faster, make slightly more power, be lighter thus the car will be faster, be more durable, offer more hood clearance, better header clearance, and be a more interesting conversation piece. In fact, you could easily turn a 451 build into a 470” build for perhaps about the same price.... he’s buying pistons anyway no matter what, and I believe there is a 6.76 Rod 470 piston available from KB.

PS: someone earlier suggested selling both of them and getting a 383.... whatever you do, don’t take that advice.
 
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Where is the weak point in the blocks from the 440 compared to the 400?
 
I have a 451 in an A-body. And am a strong believer in that stroker. The advantage of the 400 is bore size. One of the arguments was it has smaller mains. But turns out they produce less heat. From less friction. And of course the shorter deck means lighter rotating assembly. I call it the big block that thinks it's a small block. This is the same reason of Chevy's success with the 396.
 
JG71B said:
Where is the weak point in the blocks from the 440 compared to the 400?
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I’m not sure I would call it a “weak point”, as RB blocks are pretty stout. But the bore sleeves in a B block are lower, saddled in much tighter to the mainline webbing. It wouldn’t take long looking at two side by side to se the inherent strength advantages of the B series block. They’re just more compact so the crank throw has less leverage on the main webbing. The other advantage is simple: bigger bore.
 
I really have not heard any hp numbers in this thread that are going to push a good 400 or a 440 to a failure. The main thing is to get a good block with good cylinder wall thickness that doesn't have coreshift or cavitation,corrosion. Basically, a thin spot in the water jacket causes a weak spot were a crack can start on a high hp build on either block. That means sonic check them if you can. Yes, a 400 in theory should be a bit stronger w the things described but either block can fail. Big hp and old blocks its hard to say, either can fail.
ITS very possible your 440 is the stronger block if your 400 has a thin spot or vice versa. If you don't sonic check it...you may get lucky, or there may be a day when you have to sleeve a cylinder from a crack developing. Usually antifreeze gets in the oil.......usually.

We have cracked cylinder walls and pulled rods in 2 past 550hp. You usually can sleeve a cracked cylinder, a cracked main web or a hole through the block from a losing a rod is often game over.
The same stroke can fit in either engine but seldom do builders go past 512 on the 400 because things get tight. The big plus of a 440 is more room for longer rods and taller pistons, but more weight and less header clearance, but unless your racing or trying to drop a bb in a A body the difference isn't a lot. It depends on what your doing as to what is best. The 3.75 stroke b is popular, but guys are doing it less cause the 500 is almost easier if you buy drop in parts. But nothing wrong with a 452.
 
Carcinogen said:
I vote 400

Currently running 440 in 72 Satellite considering building a 400. A bit less weight up front for better handling and more room for headers would help make up for 40 less cubes. My use is mostly steady running on the highway, so the short stroke 400 would run like 383s I've had in the past.

That and gas prices are probably be at $5.00 a gal soon.
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drhill said:
The 318 is built and is a high reving engine and has been alot of fun but doesn't have the bb torque. The other thought was to turbo charge the 318.
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Now your just talking silly :)
 
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