Putting together my spare block and will be using parts I already have / spares. I plugged all my data into the Compression Calculator etc. Did I input the correct info. Mainly the cam specs.
Shooting for pump gas friendly motor. If I entered the cam data correctly it looks like this will be fine. Got confused with Lobe Separation box.
Quench distance of .041 and 7.66:1 DCR is doable on the big chamber 455, but retarding the cam 2* would put you in a safer zone on premium pump gas. I would recommend around 7.5:1 DCR for good quench and 7:1 DCR for no quench on a Buick 455 with iron heads using 93 octane ethanol infused gasoline and a 180* thermostat (no more than 210* ambient temps--185-195 is ideal). Get others' advice on this too, if they'll chime in. The figures I give are conservative (safe). You don't want to push your detonation threshold too close to the borderline with variances in pump fuel quality or decrease your chances of success with errors in calculations or other unforeseen circumstances surrounding your engine's tune and build characteristics, such as ambient temperatures that could fluctuate, combustion chamber hot spots, piston shape, type of exhaust valves used, valve seat condition, fuel mixture ratio, ignition, etc. etc. It's always best to 'build in' a safety margin for daily/street driving goals. It's also better to have lower DCR so you can get the most out of your ignition advance, vs having to retard your timing because your DCR came out too high for the grade (and quality) of fuel being used.
Richardo, What is this going in?... Detonation sensitivity is largely based on load, so a motor going into a GS with 3.42 gears, vs a Riv with 2.93's, or an Electra with 2.56's, will be significantly less prone to detonation, given the same build. Need the specs type of vehicle type of trans- if auto, type of torque converter rear gear ratio and tire size Doing any towing or hauling? JW
Here's my plan / current project I'm working on. 72 Skylark GS Convertible Engine Block 1975 455 that's been zero decked / .030 over and L2353F pistons 27.8cc no valve reliefs Heads 73 heads, stock valves / valvetrain with just basic port matching and smoothing out the combustion chamber area. GS116 cam stock exhaust manifolds Edelbrock Performer intake Current trans in car is a 4 speed, possibly switch to 6 speed (close ratio) Rear gearing 3.42 (4 speed) or 3.73-4.10 (6-speed) Tire / total height 25-27in Thanks
