What is the optimal cubes? Is it better to have the biggest stroke, or go with a certain ratio?
Just my observations over the last few years , people who build 426 Supercharged CI G3s don't seem to run any faster then those who build 392-411s , and in theory if your making 1500Hp with 35X-37xCI you should make 1800 with 420-430ci , granted
I know it's not a direct correlation HP/Ci/Airflow , but you can't tell me that Extra 50-75Ci creates 300hp worth of friction at that level of a build.
Looking at what Rob Goss has done and what the blown FS cars run with the 2.9L Whipple I think 355-400CI is the optimal CI, with 411 being the "big" end for the G3 platform ...The FS cars are 354/355Ci running 7.50s at 3500 lbs race weight , Rob's Billet G3 is "400"ish I don't think you can get enough Flow out of the G3 heads to support 426-440ci supercharged certainly can't get enough cam lift to support big HP#s with the off the self heads and shaft rockers, Thikit(sp) and individual rocker set ups will get you up in to the .700/800s lift and 400/430CFM .
My TFX hemi is 503ci (504 if you round up) with a F3x140 Procharger uses every bit of that low 500CFm at .9XX lift to make 2750hp. which is 5.46HP/ci vs the FS 4.20(ish)HP/ci
The FS cars run 4.09 bore with 3.40 stroke with 6.30 rods , not sure what Goss's combo is, the older 5.7 stroker 392/394 CI set up, 3.917 - 3.937 x 4.05 makes good power if you can keep the block from breaking, and personally I think it has to do more with the hockey puck height piston than the block and 1.4X rod ratio.....with 6.10 rods your looking at 1.125 pin height and 6.125 rods you are looking at 1.09 pin heights , the FS cars run a 1.27/1.28 pin height. the Hellcat/Demon/Redeye run a 1.28 hence the issue with the 9.24-9.28 deck height of the G3 blocks limits stroke and the 4.46 Bore spacing limits bore to 4.09/4.10 and still have .200 cylinder wall. anything less and you're giving up HP potential. My uncle had a 362ci 5.7 with a Kenne Bell and a Big mouth TB lay down 1150hp thru a TH400 in a 2008 Charger about 3 weeks back over at a friend of his dyno shop,
I've seen a few of those 394ish based 5.7s around the East cost running 7.30s/180MPH which works out to 3.50 HP/ci , ones is a 86 Fox Body Mustang @ 2750 the other one is a 84/85Daytona RWD conversion ....I know one of the guys my uncle bult a 397 with a 4.5L whipple for is a 73/74 satellite that was running low 9s, I know that car was close to 4klbs and they broke a few early 5.7 blocks. the 426CI 6.1 that was in the car never faster then the 397 combo , it ran about the same .,the best run was .1 slower next engine for that pig most of it was bought from Schumacher, block ,heads Plan is to build a 360/370ci short rod with 1.3X Pin height and 6.2something rods.