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440 rebuild questions

Started by flyinlow, January 16, 2021, 11:32:13 PM

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flyinlow

440 rebuild questions;

Can you bore past plus .060'  ?

Do lighter ,shorted forged pistons like SRP  wear faster? Do the rings wear faster with the pistons rocking when cold. I used them on an other 440 build and the have gone 50K. so far but are noisy when cold.

What is the desirable piston to head clearance on closed camber aluminum heads?


Challenger340

Quote from: flyinlow on January 16, 2021, 11:32:13 PM
440 rebuild questions;

Can you bore past plus .060'  ?
You can Bore a Block to any oversize you want as long as sufficient cylinder wall thickness remains for it to be viable in operation.  .060" over is typically the MAX recommended overbore on a BB Mopar as cylinder walls are not thick enough past that..... use a sonic testing device to check Wall Thicknesses.
Cylinder Wall thickness is also Heart dissipation.... thicker is better.


Do lighter ,shorted forged pistons like SRP  wear faster? Do the rings wear faster with the pistons rocking when cold. I used them on an other 440 build and the have gone 50K. so far but are noisy when cold.
SRP Pistons are usually a 4032 High Silicon alloy and should not be very noisey if at all when cold. Piston weight does not affect 'wear'..... but incorrect clrc in the Bore can, which, depending how sloppy the 'fit/clrc' they are in the Bore may accelerate both Piston skirt and Piston Ring wear.

What is the desirable piston to head clearance on closed camber aluminum heads?
Depends upon application, typically if pursuing a 'quench' characteristic in the Piston to Cylinder Head dimension then .050" is an accepted target, although this .050" dimension should NOTimo be confused with BEST quench distance for horsepower output, as we have seen/proven on the Dyno higher HP numbers with BB Mopars by increasing quench dimension well past .050".... again, depending upon application/Flow ratio and actual Bore size.



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