Swapping 305 50L engines

"Help- I allowed my mercruiser

"Help- I allowed my mercruiser 5.0 L gas engine ser.#0F429852 MCM#450B100HS to freeze last winter. I am wondering if I can use the following for an exchange - OMC modl# 502STHRCRA,
ser.#J808164 I am quite sure both are GM 305's. If they are interchangable what major problems might I face? Thanks, dean"

Are you planning on just using

Are you planning on just using the long block from the OMC and swapping the Merc. parts to it?

"As guy said

If you are pla

"As guy said

If you are planning on using only the motor you can swap out the carb, ingition, altenator, flywheel and housing, all electrics.

Again just the long block. A chevy 305 is a chevy 305. If youhave access to a 350 as easily as it seems you access to a 305 than I would just go to a 350.........All the items listed ablove will fit with the expection of the carb. You should if it is not allready included, get a 4 bbl marine carb."

"Ayuh,....

If you're th

"Ayuh,....

If you're thinking of swapping the Complete OMC motor into your boat,....

It just Won't Fit....

If you strip it,+ use the Merc. parts to dress it out,....
No Problem..."

"502STHRCRA is 1984. If your M

"502STHRCRA is 1984. If your Merc is newer than 1986, you may have a coupler and flywheel mounting problem. Otherwise as mentioned above long blocks of any particular year are all the same Merc, OMC or VP of same year. pretty sure they all came off the GM engine line in the same run. Probably 3 or 4 days to make all marine engines for a year."

"Thanks guys- I planned on pri

"Thanks guys- I planned on primarily using the block, My exhaust manifolds cracked also but could use other Merc components switched over.... I got a curve on that flywheel/coupler problem. Can someone elaborate? Also, my Merc is a '95.
dean"

"1984 crankshaft has a differe

"1984 crankshaft has a different bolt pattern on the back end than your 95, so your 1995 flywheel and coupler will not fit - you'll need an old flywheel and not sure, but the OMC flywheel that's on it *might* be the same. And you will probably need an old style Merc coupler and studs...(the 1984 omc coupler is something totally different -rigid) -unless the old OMC flywheel has the perimeter bolt holes for your 1995 coupler....some old flywheels did and some didn't.
I just did this on my V6 - pulled a 1992 motor and put in a 1983...i bought the old style coupler and studs and then later realized I could've used my newer merc coupler - my old V6 flywheel actually has the perimeter threaded holes...oh well..I have a new coupler now and that never hurts"

"Thanks again... I will report

"Thanks again... I will report back on my progress, but plan on it being a winter project. d."