I had the numbers typed in wrong. I have always used .7854.
Who has used a 440 crank in a 383 block?
- Thread starter Kern Dog
- Start date
I use this formula: Bore squared x Stroke x Pi x 2 and this will give you cubic inch to the exact decimal point.
Tom
Tom
Minus a few pounds
This isn't exact, and it is only close for an 8 cylinder - nothing else.
Cylindrical volume is πr²*H (H=height=stroke) for one cylinder - then multiply that by cylinder-count.
If you don't know Pi (and your calculator lacks the function), the number is a fraction: 22/7 = 3.142.... (approximating an irrational non-repeating decimal)
For this exercise; Bore radius '2.125' squared * Pi * 3.75 = ~53.22ci per cyl.; times 8 = 425.64ci
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If I remember correctly - Pistons where about .023 in the hole
Used there chamfered B engine full groove main bearings
ARP Bolts internally
Edelbrock E Street Heads 5090 - 75cc
Fel Pro .039 Perma Torque Head Gaskets
10.5 to 1 - 195 PSI Cranking on all eight
Comp XE - 275HL Cam Lifters
16 - 18 - 34 Total Timing
Edelbrock AVS 2 800 CFM
Have to run 93 Octane 10% Ethanol here in WI
Numbers Matching Block , hence at the time probably why I decided to keep it low key at 432
Thought really hard about the 496 kit
Almost said screw it all together after waiting over six months for the machine work on the block to get done - 440 Source Kit obviously was delivered already
Was going to buy another completed motor at the time , honestly looking back I wished I would of
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That is great! Thanks for responding. That is a great looking car. I saw the ridges at the edges of the fenders and thought Barracuda.
Rod to stroke ratio was mentioned but not really discussed.
As soon as you get into stroker engines, you should be concerned about the rod to stroke ratio. A general rule is you need to be at 1.5 or higher. So for example a 4" stroke should have a minimum of a 6" rod. This ratio affects piston speed and the angle of the connecting rods, plus more.
In any engine, obviously the depth of the bore is fixed. So as you increase the stroke, and in turn increase the rod length, the only way to fit it in is to shorten the piston. This is why you see short little pistons in many stroker engines, including where the wrist pin moves up into the oil control rings necessitating support rails.
As soon as you get into stroker engines, you should be concerned about the rod to stroke ratio. A general rule is you need to be at 1.5 or higher. So for example a 4" stroke should have a minimum of a 6" rod. This ratio affects piston speed and the angle of the connecting rods, plus more.
In any engine, obviously the depth of the bore is fixed. So as you increase the stroke, and in turn increase the rod length, the only way to fit it in is to shorten the piston. This is why you see short little pistons in many stroker engines, including where the wrist pin moves up into the oil control rings necessitating support rails.
33 IMP
Well-Known Member
460 Ford flat top, .030 over would be a .048 overbore of a 400 Mopar. With a stock bbc rod, It would be almost .200 in the hole.
A 6.350 (200 long) bbc chevy rod would be .017 out of the hole, assuming a blueprinted deck, would work fine with an open chamber bbm head.
But then again, who knows what shenanigans were done by the crank grinder.
Offset grind for more stroke, and use standard bbc rods maybe?
Interesting build.
Edit: I thought about this some more. Maybe he used 429 (not boss) pistons. Same bore as a 460, shorter stroke, so more compression height to pistons, maybe not near as deep in the hole as 460s would be with a stock bbc rod. (Pin end of bbc rod would have to be bored/honed for bigger Ford piston pin).
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I'm fairly sure that he used a factory Chevy rod in it. I recall him talking about the larger 7/16 rod bolts for strength
I did reach out to a family member and offered to buy the car and motor but haven't heard anything back on it.
The cheapest easiest is still a 440 with some big Ole pistons , like a L2295 and the biggest port heads you can get. No need to become an at home novice engineer.
This is what I have in my ‘68, plenty of tq down low.
I'm not against that. I just stumbled upon this modified crank and thought if it were a simple deal, I'd pull the engine to swap cranks. I didn't know what it actually entailed.
Before the affordable longer stroke cranks became available, stuff like this was more popular from what I understand.
Curiousyellow71
Well-Known Member
Before you go any farther measure the modified crank you have, rods/mains and counterbalances. If the mains were cut observe what the fillet looks like... for higher hp builds a wider radius prevents cracks. We broke a 451 crank because the fillet was too sharp when they cut it.
A 440 cranks larger counterbalance usually rubs on the block. You can have the counterbalance turned down to B size(may be already) or take a grinder and make clearance in the block. Both methods work.
As far as rods/pistons I have not seen any 3.75 strokers that don't use 440 6.76 length rods? Some have a .990 pin some stock 1.094 mopar pin.
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Last week I used my cheap Harbor Freight press to push the pins out of 2 sets of stock pistons. I was surprised to feel how heavy the pins are in these engines. One piston had a pin so stiff, I bent the rod trying to press it out. I've seen my machinist heat up the little end of rods before pressing them in but what do you do for a piston and rod already together? I didn't care about saving these stock pistons. Some crumbled a bit at the skirts since i did a somewhat crude and uncaring method of removal.
Geoff 2
Well-Known Member
Folks should think about stroker engine combinations that outperform engines from the same company that have the same cu in. A Chrys 408 stroker v a Chrys 400; a 383 Chev; 347 Ford.
It's the rod/stroke ratio as I alluded to in my post & Hawk rod in post #30. It is also the reason for this warning.
It's the rod/stroke ratio as I alluded to in my post & Hawk rod in post #30. It is also the reason for this warning.
Breaking pistons is common, but bending rods? It sounds like you are holding the rod, and you shouldn't touch the rod.
Lay the piston in press with the pin pointing up.
The bottom of the piston must be supported (ideally with a half round cradle that has a hole in it to allow the pin to come through). Better yet, a small piece of metal that just goes around the area of the piston where the pin comes out - this is the strongest area.
Then push the pin on the top side through the piston down and out of the rod.
1KoolBee
Well-Known Member
Or offset grind rods to BBC Journals and 3.91 stroke, use 6.700 BBC rods and diamond 51950 pistons for 451. Side clearance will be big unless you find rods (Manley 14279-disco’d) or crank (440 source) designed for this combo. Some people have done this with standard parts and side clearance apparently not an issue if you control rod bearing clearance.
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