But does anyone know what my compression raito should be for a slant six to add a turbo charger or super charger?

Its going to depend on a few hundred factors; cam choice, type of piston, what work done to the head, RPM range desired, EFI or carb? blow through or pull through? How much boost?

Way too many factors to just guess. The answer could be 6.5:1 or 9.5:1

We have a forced induction forum that might help better. I'm copying it over there.

Ok, thank you for that. But I have a stock 1978, 225 slant six, with the super six pack. Does that help?

Also what octane and type of fuel and driving/load would be helpful.

1978 stock ratio? (8:1)may be just fine for a mild street set-up with high octane pump gas.

Also what octane and type of fuel and driving/load would be helpful.

1978 stock ratio? (8:1)may be just fine for a mild street set-up with high octane pump gas.

I plan on running 92 octane or higher, and only driving on the weekends maybe slightly more and only the car and myself maybe a friend wich may total an additional 320 pounds as I only was about 145.

Is that better?

8:1 can probably run up to a 7-8 psi without cooling. 10-12 psi with cooling.

8:1 can probably run up to a 7-8 psi without cooling. 10-12 psi with cooling.

Thanks a lot. So does that mean I can run a turbo without an intercooler?

You can probably get away with a low boost system on 92 octane gas without an intercooler.

You can probably get away with a low boost system on 92 octane gas without an intercooler.

Awesome, so you guys should see some pictures and videos of a turbo charged hyper-pak volare some time within the next six months!