WebOct 21, 2009 · 149 Posts. #16 · Oct 16, 2009. That 400 with a dishtop piston is usually around 10 to 1 or 10.5 to 1 compression with 64 cc heads. That is figuring a 12.5 cc dish which is what most of them had. That is borderline with pump gas. Use 93 octane and some octane boost to be safe. WebSep 29, 2016 · stock compression height pistons piston dish/valve relief----compression 7cc -- 9.75 12cc -- 9.35 18cc -- 8.71 Regarding the cam, that's a function of vehicle weight, transmission type, overall gearing, and intended usage. But you're right to choose a cam duration and compression ratio that work together.
Understanding compression on a pump gas street motor - Engine …
WebMay 16, 2006 · COMPRESSION RATIO DEFINITIONThe CR is the ratio of the volume above the piston at BDC (left) compared to the volume at TDC (right). The formula for … WebGM 7.0L V8 LS7 Engine Specs; Type: 7.0L Gen IV V8 Small Block: Displacement: 7008 cc (427.6 ci) Engine Orientation: Longitudinal: Compression ratio: 11.0:1 spine cage surgery
sbc 400 compression ratio with 64cc heads - Chevy Tri Five Forum
WebSep 27, 2024 · While these heads will bolt right on a small-block Chevy, there are several caveats that you should be aware of before you torque those head bolts down. ... That creates an 8.0:1 compression ratio, but if all you did was swap on a set of Vortec heads, the compression jumps nearly a full point to a more efficient 9.0:1. With a common, four ... WebFeb 19, 2024 · All these engines are chain-driven and have a compression ratio of 8.2:1 and up to 11.0:1 and this tells you a lot about the durability of the small block engines. ... The 400 small-block Chevy engine is rare but can be used to build a budget Gen I small-block engine with increased torque and power. WebApr 10, 2024 · We plugged in this new number into the calculator and it gave us 9.7:1. This is not a bad ratio for a mild street small-block running on 91 octane pump gas. The beauty of this simple compression ratio calculator is that you can quickly juggle different combinations to come up with a preferred compression ratio. spine candles harry potter