Stroker crank in 360

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dustoff440

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I cant seem to get a straight answer to a question I have, WIthout getting new pistons and rods, can I put a 4 inch MP stroker crank in a stock 360 magnum and still have the same TDC I had before the install??
What I'm trying to do is put a stroker crank only in this motor without having to do any thing except clearance the block for the rods. I know that for maximum effect I need aftermarket pistons and it would be nice to have scat rods so I dont have to clearance the block. I want to go on the cheap and install a crank ONLY. WIll the new crank change the TDC position of the piston in the bore or will it remain the same. I would like to retain the standard CR of 9.1 to 1 or greeater
 
I'm no professional but have been working on a stroker build myself. Look at it this way. If the stock crank stops the pistons at the top of the block deck, then where will the pistons stop if you add, oh say .50 inch to the stroke? My guess is, not before they hit the heads which might not be to good. Hope this helps and I hope my assumption is correct. good luck.
 
You will need shorter pistons to make up for the longer stroke.I bought the eagle kit and am very please with the engine.:toothy10:
 
No, you can't. The crank's stroke represents a distance... In the stock one's case its 3.58/2 or 1.790". That is the amount od space the crank takes up from the centerline of the crank bearing bores to the deck surface. The rods take up another 6.123", and the piston's compression distance (from the centerline of the pin to the op of the dome) make up the final bit. I think on a stock type piston its 1.610" or something like that. That leaves the factory piston about .070 down in the bore. The problem is the deck height of the block doesnt change. So if you replace the crank with a 4" arm, you now have an additional .210" of crank there, and the piston will pop out of the bore by .140". So you must use shorter pistons.
 
Shorter piston is needed. the stroker crank puts the center of the wrist pin higher in the cylinder when its up so you have to run a piston with a shorter center to top of the piston.
 
you need pistons with a higher pin height to offset the increased stroke.

also you may find you need to more than just clearance the lower cylinders for the rods.. the crank can come mighty close to the mains as well depending on who cast/machined it.
 
Aren't the rods are the same length, and will they work with the extra HP/torque of a 408?
 
Aren't the rods are the same length, and will they work with the extra HP/torque of a 408?


Yes and to a limit...the limit being rpms and hp.

Now there is Chinese H rods available (around $400) and maybe even better--for like $1,000--lol

I got to wounder if these strokers can last a long time--like the 3.31 stroke motors can? Or are they getting worn out by 25,000 miles? Seems so much stress on the pistons and walls and being shorter pistons makes the wear happen even quicker.
 
I just wonder...because my rotating assembly is a MP 10:1 short block..not sure what they used and what they can handle.

BTW, dustoff440, not tryin to hijack thread!
 
No, you must get new pistons....Rods are the same length....
 
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