Which Flange A/R housing

[bnova]

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?

 

[howdies86]

It's cheaper to buy an adapter for 3 bolt to 4 bolt. I think RJC makes them. A local machine shop made mine several years back for about $20. It only raised my turbo up 3/8 inch.

 

[bnova]

Yeah, I know. I can make the flange at work as well. My issue is the headers that were bought for the motor are the cheap Ebay SS headers. All quality parts in the motor, and crappy set of headers. This was this way when I bought the motor. I was thinking of modifying the headers(cross-over), and the 3-bolt flange. Cut-off the flange, and weld on a 4-bolt.