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Okay I know this is a silly question and I do not have a 4.6 car but if I take say a 96 gt and put some good aftermarket heads and cam on it. Will it make the same horsepower as a PI 4.6 with the same aftermarket heads and cam on it. All modifications being equal. I guess I am asking if the bottom ends differ from non pi headed 4.6l to a 4.6 with pi heads
 

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The pistons on a NPI and PI engine are different, the Pistons Dish size on a NPI 4.6L are about an 10cc-11cc, and I believe that the PI engines have a 18cc dish size. So if you put the same 44cc Chamber size head and cam on either engine, the NPI engine will see slightly higher numbers due to the increase in Compression ratio.

Note: I BELIEVE that the Romeo PI engines had a 15cc dish size. Compared to the Windsor PI engines having the 18cc.
 

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Okay I know this is a silly question and I do not have a 4.6 car but if I take say a 96 gt and put some good aftermarket heads and cam on it. Will it make the same horsepower as a PI 4.6 with the same aftermarket heads and cam on it. All modifications being equal. I guess I am asking if the bottom ends differ from non pi headed 4.6l to a 4.6 with pi heads
Do some research into pi vs NPI. If you put pi heads and intake onto an NPI block it will make more power than a stock PI motor due to the increase of compression. This is what i am doing with my engine. It is a great mod for these NPI cars and really turns them into pretty quick street machines.
 
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