Thread:

Holley needle and seat for 660 4 barrel Double pumpers.

Does anyone know the needle and seat number for the old 660 4 barrel carbs with mechanical secondaries? Thanks.

Originally Posted by gn7

6-504 for the .110 aseembly

Thanks Bob. Do you know if the 110 was the original size or was it the 097? Is there any downside/ upside to running the larger 110 size versus 097 ? I also see that they make 078, 120, 130, 150

Originally Posted by gn7

The larger the needle the less fuel pressure you can run without over coming the needle. The .110 is about as big as you can go with the side hung floats. Keep the fuel pressure in the 5-6 lb range.

Thank you Bob!