Chevy sbc exhausts- optimum primary lengths???

[M Blur]

Hi Chaps,
My custom zaust builder has asked what's a good primary length from manifold to collector (4-1) for a slight short stroke - over bore Dart 358cid? Usually approx 26", right?

Cam is a 286deg with peak torque approx 5800rpm and power up at 7400rpm. We're looking to save most of that top-end but make the zaust a bit more driveable given the lump cam.

we're using usual bore dims with 12" cans for some back pressure and possible moroso sound baffles.

what's the lengh you guys are running?

Cheers
Jon

[P15TON]

Try 32" as a more likely figure.
Back pressure is for two strokes.