Don't be afraid to run the plastic one ernie

Thanks for the answers guys re backplate material.About that rod rubbing the inside of the backplate,next time i pull an engine out i'll have a real good look at that and see.It's interesting because i've got an 82 i rebuilt about three years ago and when that flies by it makes the oddest light rubbing sound i can't descibe the tone.I wonder if that sound would be louder with an aluminium backplate? or maybe thats the engine i put a rod in backwards onto the crank.