Gasket location hydratech

[hpg4815]

I bought a firewall gasket kit from Detroit muscle and I am not sure if the one pictured goes on the inside or outside of the firewall. I’m thinking I would have one on both sides but the kit came with one. I am not going with the original booster but a hydratech hydroboost setup. I’m thinking I can put this on the inside and use felt paper on the outside if necessary? Thanks

-Hiram

 

[pnora]

Outside under the hood.

 

[hpg4815]

Outside under the hood.

Thank you