Hello,<br /><br />I have a '72 merc 500 and a '77 merc 500. The '72 has a good powerhead but some ignition parts missing (Thunderbolt Type II), The '77 has a fine Type V Ignition, but a stuck piston 
<br /><br />Well, you guess it, i would like to put the ignition of the '77 on the powerhead of the '72. Those powerheads are the same from 65-79 regarding to my Seloc Manual. But the exhaust cover looks different. Now i wonder if i could put the exhaust cover on the '72 too. This is important since there are some "stoppers" for several screws on this cover. I know that the crankcase cover and the cylinderblock are a matched set, but what about the exhaust cover? <br /><br />I will see if it is possible to upgrade the ignition though, because there are some parts below the flywheel on the newer motor (the complete timing). I don't know if it is possible to mount them on the old powerhead...<br /><br />Many thanks<br />martin
<br /><br />Well, you guess it, i would like to put the ignition of the '77 on the powerhead of the '72. Those powerheads are the same from 65-79 regarding to my Seloc Manual. But the exhaust cover looks different. Now i wonder if i could put the exhaust cover on the '72 too. This is important since there are some "stoppers" for several screws on this cover. I know that the crankcase cover and the cylinderblock are a matched set, but what about the exhaust cover? <br /><br />I will see if it is possible to upgrade the ignition though, because there are some parts below the flywheel on the newer motor (the complete timing). I don't know if it is possible to mount them on the old powerhead...<br /><br />Many thanks<br />martin