Thackdaddy
Well-Known Member
Except for having them custom made ($$$$$) there are none being made.
400 with 440 pistons
- Thread starter Thackdaddy
- Start date
66Satellite47
Well-Known Member
For what the OP is going for a custom piston seems like the correct plan. A bit more expensive, but you get a proper combination.
Hemirunner
Well-Known Member
Are you against using a used piston?
Fizz66Coronet
Well-Known Member
I would find a used 440 crank.
Thackdaddy
Well-Known Member
Have something?
Curiousyellow71
Well-Known Member
The 383 and 400 are both similiar builds using 440 pistons. Using 440 pistons gets the compression near the 68-69 383hp piston(which no one makes). But.....It's pretty hard to get a honest 10:1 using 440 pistons unless the block is squared up and surfaced. Even though a b engine deck height is suppose to be 9.98 not many(if any) were built that way and were perhaps 9.995-10.0?. So if you want 10:1...start by decking the block and squaring it up. Even with the 440 pistons at 0 deck your compression will be about 9.3:1 using a 452 and a .039 gasket. To get to 10:1 you will have to get the head cc's less. .020 head gaskets is also a option to boost it. Since 440 pistons have no eyebrows I'd suggest choosing a cam .500 lift or less. Guys have run the mp .509 and that is about all that fits with no valve reliefs..but that is going to vary.
The kb pistons are pretty low compression... but they take care of the valve clearance problems. They can be machined for 0 deck...but it seems the price nearly doubled in the last 6 months
We have 440 pistons in a 383. Block has been decked to where we are .005 out. We cut valve reliefs and are running a 704 voodoo. IMHO...Be careful what you wish for if you want a pump gas engine and 10:1.
For pump gas 9.3-9.5:1 is safer if you are going with a smaller cam. 10:1 needs a cam with some seat timing to run well on pump gas and will take some machining to get you there.
The kb pistons are pretty low compression... but they take care of the valve clearance problems. They can be machined for 0 deck...but it seems the price nearly doubled in the last 6 months
We have 440 pistons in a 383. Block has been decked to where we are .005 out. We cut valve reliefs and are running a 704 voodoo. IMHO...Be careful what you wish for if you want a pump gas engine and 10:1.
For pump gas 9.3-9.5:1 is safer if you are going with a smaller cam. 10:1 needs a cam with some seat timing to run well on pump gas and will take some machining to get you there.
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66Satellite47
Well-Known Member
I agree with Curious, back when I was collecting 440 & 400's, we measured most of 400's in the 9.995 to 10.00 range. Perfect since was having the block milled & squared. Both my 400 motors came out at 9.98 after machining. Also agree that a true 10.0 CR would be on the edge or a little high with today's gas. Cam selection would be critical. Fly cutting the pistons for valve clearance should be no problem with most of the 440 pistons. You need to determine which bore size 440 piston you need, .030 or...? A 452 head has enough meat to adjust the CC's a fair amount to dial in the CR. To accurately determine the TRUE CR you need to measure the deck height, chamber volume and valve notch volume. Then do the math. Relying published numbers can lead you far astray.
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