I used the stock 85-93 Mustang vert mounts. The engine was/is moved back to where the drivers side head has about 3/4" clearance to the firewall. The engine is centered between the fenders. The 89500's drop right into place too, but the elbow being crushed by the axle, plus the starter not being able to be removed without removing the header are the two reasons I went to Tri-Y's, (after trying to modify a 65-66 Mustang 351W swap header to replace the right side). The 88400's solve the problem of the 89500's right side. The 88400 left side is identical to the 89500 left side. We've tried to tell Hedman this, but as Wade already posted, it all fell on deaf ears there.