Depending on the year and model there are two compression ratios available but I just looked up the 1978 8.5 copression model and it is a 165 hp with a 2 barrel and the smog crap. I am pulling a 305 out of a car right now and am gonna see what I can make it pull hoping for 325 HP with under 600.00 I will post the results. Hope this helps. The 305 has great low end torque.