I thought I would post my results on modeling the 292. I am not 100% sure I have a representative model, but I think it is getting close to having something that I can make changes to and see effects.
To get curves that match a stock 292, I had to model the siamesed input ports as a plenum and the intake port lengths as (very) short. Basically the port length is the length after they split from the siamesed section. (Modeling the siamesed ports as a plenum has been suggested by others.)
Unfortunately, I can't post pics, but here is some tabular data of torque in lb-ft.
The "stock" GM data is something I dug up from a GM publication.
RPM GM Model Delta
1600 280 260 20
2000 276 263 13
2400 272 260 12
2800 264 251 13
3200 252 241 11
3600 236 224 12
4000 212 201 11
The model curve follows closely with the exception it is not predicting the torque peak quite as low as the actual data. The data peaks around 1600, the model peaks around 2000.
