Magnum 57 build (part 3)

[James Crewe]

As the engine was already in place the next task on the list appeared to be the fitment of the exhaust and header. This kit consisted of the exhaust itself and a bag containing a header, O-ring, gasket, 2 x screws & washers, an exhaust coupler and 4 tie wraps.

Exhaust kit

What was missing though was the header cooler shown in the instructions. At this point a quick call to WH (Tony) revealed that the new header didn’t require the cooler and the coolant from the head would connect directly to the inlet at the mid-point of the newly designed header (phew!).

The whole assembly was trial fitted first; this was a worth while task as I found that the holes in the header didn’t quite like up with the head, a little fettling was necessary. Once this was done the fit could be tested and with the head bolts pinched tight I could see that the gap between the header and the exhaust at the coupler was about 3mm (perfect!).

Lots of trial fitting was required

I now kept the exhaust and header together (as the correct length had been established); I then applied and tightened the 4 tie wraps to hold the coupler in place (although this is very tight anyway).

Exhaust and header now as one (with tie wraps)

As per the instructions I now slid the O-ring up the pipe (out of the way temporarily) and added a bead of silicone to the exhaust at the point it meets the transom. I then carefully positioned the end of the pipe through the transom and bolted the header to the head. Once this was done the O-ring was slid into position against the silicone to seal the back of the transom. The excess sealant was then cleaned up...

Final fit was great...