merc 4.3 rebuild - cracked block

I am rebuilding 2 1990 Merc 4.3L engines. First one no problem. On inspecting the second block I found 2 cracks. I have looked but apparently I can no longer purchase a new bare block and I have had difficulty finding a used bare block or core to rebuild from.

I have all the internal parts, heads, exhaust, ect in new/good condition so I prefer to just rebuild off of a different block.

I have looked at automotive blocks. Looks like 87-91 4.3 (262) have the same casting #'s 011 and 867 (I have 867) but I cant find one with a fuel pump on the block. I'm afraid the block won't be drilled for the pump push rod.

Does anyone know if I can use an automotive block and which one, or know where I can find a marine bare block or core to rebuild from?

 

Call Rob at 407-767-2026.

 

You can use any 4.3 block from 87 to 92, as these are roller cam blocks without the balance shaft. The engine you want was designated as the 'Z' engine, at least in the S-10 trucks. The reason they don't have mechanical fuel pumps is that they were fuel injected, had an electric pump in the tank; although they do have a fuel pump boss.

I'm not sure if the later engine with the balance shaft, the 'W' engine in the S-10 trucks, has a mechanical fuel pump boss or not, although the 96 and later vorted heads are worth looking at as a great mod.

You might want to consider, since you're rebuilding the engine anyway, going with a set of vortec heads. They are a 30 hp bolt-on even without porting, and Edelbrock sells the correct manifold to attach a carb to these heads.

 

It is possible to use an electric fuel pump if you also add a safety cut-off switch that works with oil pressure.