1975 90hp oversized pistons and rejet carbs

[72INVADER90HP]

I want to rebuild my 1975 chrysler 90hp 907hd and put oversized pistons, why change the Jets on the carb? The motor was my wife's grandfather's and he thought it would never run again but I got it running for 2 years but I want to keep it in the family so I have elected to rebuild it.

 

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Re: 1975 90hp oversized pistons and rejet carbs

Oversized pistons will increase displacement, HP, and fuel demand. It will require larger jets so it doesn't burn too lean thruout the power band. If you don't, it will grenade somewhere down the road, and will need even larger pistons, and larger----well, you get the idea

 

[72INVADER90HP]

Re: 1975 90hp oversized pistons and rejet carbs

thanks for the reply I will try to figure out what size jets to goto because my manuel does not specify what size Jet

 

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Re: 1975 90hp oversized pistons and rejet carbs

I do not know what the stock jets are. But a very safe rule-of-thumb would be to go the next size up from those, if you go the next available piston size from original. They should be stamped on the slot side with the size.