Gen 3 426 into aussie a body

Here's what I can confirm -

I had to re-position the brake booster AND run the smaller Hemi 6 booster to get adequate clearance for my #6 and 8 coil packs for my 6.1 - so Im betting a 426 will really cramp your brakes cylinder.

Id suggest a remote booster under the guard.

I know Valiant Spares used a Hemi 6 K frame for a 6.1 conversion as it set the motor lower at the front than the small block one - again a good reason to call them.