Best Compression Ratio for Whipple

I am looking to purchase a livernois pro series short block for my whippled GT. I plan to run stock heads, cat delete and I am limited to 91 octane. Livernois offers either 10.1 or 11.5.1 compression ratio for their short blocks. Which would be the best ratio for my set up and what pulley size would be recommended? I want to make as much power as I can while making it a reliable daily driver on 91 octane.

If it is going to be a street car do the 10.1…

i would also say 10:1 for a 91 octane car, it will be more forgiving

Save the money and run stock motor. It will easily handle anything 91.

Reds197 said:

Save the money and run stock motor. It will easily handle anything 91.

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This.

Reds197 said:

Save the money and run stock motor. It will easily handle anything 91.

Click to expand...

X3

I would add a crank sprocket and opg to your stock engine. You don't need a built motor with pump gas.

I just went through this since I toasted my motor when the OPG went out this past summer. I looked into built motors of all kinds, and in the end it didn't seem realistic as I'm not going over 700 whp with my whipple setup. I have 3.650" pulley stock headers and I'm keeping flight controls. Whipple recommends not exceeding 700 whp with 93 octane, some do more but I'm keeping this motor in tacked this time. In the end it made sense to get another stock long block and call it good. There are many out there making 750 plus WHP with stock motor and no issues. OPG and timing gear are a must in my book, but in reality since I already used my unlucky ticket, I could probably get away this time without OPG and timing gear. I can't believe I just said that:headbonk::doh:

10.5:1 Is the way to go. It all depends on the future goals of the vehicle. If you plan on going beyond current ambitions and would like the added security blanket, then awesome, our Pro Series block is a great way to achieve that. If not, then you can stick with the stock block but definitely go the OPG route.