I have a stage II stock stroke 250CI motor. GN1's full cnc race ported with Champion Intake and hyd. roller cam. It has 95# injectors. I have a TH400 w/brake and matching conv. to the engine. I have a Precision 76GTQ for the engine. The motor had 3-bolt headers for it when I bought the engine, and I am not sure of whether to buy 4-bolt headers and run a T4 flange with a .68 A/R housing or keep the 3-bolt headers with the .85 A/R housing on it now. This will be mostly street driven with trips to the local track. I know the T4 flange will flow better than the 3-bolt, but what difference(how big) will there be in spool-up? Your thoughts?