Re: Swapping engine advise
I need to replace my old mercruiser 898.I have access to another 305 and a 350,these are both truck engines.Which one should I go with,power isnt the issue here.Its more about suitability.Is one truck engine more suitable than the other?I know parts need to be switched over from the old merc,the starter,distributor,fuel pump and carb,are there any others that need to be swapped?and can they be swapped to the 350?Another thing,does the year matter for compatability?
Year matters for compatibility. Whether one engine is more compatible than the other engine all depends on how close either of the two donors match whats in there.
-First off, is the engine in you boat have a 2 piece or 1 piece rear main seal? Flywheels from a 2 piece will not fit a 1 piece, and vice-versa.
-I assume you probably have a mechanical fuel pump. Do the donor engines have a provision to run a mechanical fuel pump? Many of the early 90's on truck blocks are not machined to run a mechanical fuel pump.
- Are your valve covers center bolt or perimeter bolt? While the actual valve covers don't matter, a cylinder head with the latter style center bolt valve covers use a different intake manifold (bolt angle on the center bolts of intake is different) than the perimeter bolt heads. Vortec engines with vortec heads are a whole nother ball game when it comes to the intake.
-Do the donor engines have roller lifters? While you may be able to get away with using a truck cam in a marine environment, it is recommended you swap the marine cam into the donor motor. In some cases you can go back-wards from a roller cam to flat tappet, in all cases you can't install a roller cam in an earlier block without aftermarket stuff.
I could be missing more, but thats just the stuff off the top of my head.
Keep in mind you should consider swapping the core plugs the brass, and the head gaskets to marine head gaskets, especially if you run it in salt.
