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chevy omcchevrolet 2 piece rear main coupler

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cardoctorlv31

New member
Hello everyone , Have learned a lot here great forum !!

I hope someone can help me out , I have a 73 reinell cabin cruiser had a chevy 350 with a omc 225 electricshift outdrive. I purchased another 350 Chevy and i did'nt no about crankshaft flywheel diffrence's . problem is flywheel and coupler from my old engine will not fit new engine . old engine was a 1 peace seal and the new engine is a 2 peace seal , so coupler wont work . is there a coupler and flywheel that will work ? Can't return engine ...

Thank You
 
cardoctorlv31 said:
Hello everyone , Have learned a lot here great forum !!

I hope someone can help me out , I have a 73 reinell cabin cruiser had a chevy 350 with a omc 225 electricshift outdrive. I purchased another 350 Chevy and i did'nt no about crankshaft flywheel diffrence's . problem is flywheel and coupler from my old engine will not fit new engine . old engine was a 1 peace seal and the new engine is a 2 peace seal , so coupler wont work . is there a coupler and flywheel that will work ? Can't return engine ...

Thank You
Click to expand...

Ayuh,...... Welcome Aboard,.... I believes ya got that exactly backwards,....

Yer gonna have to resell the 1 pc. seal motor, 'n buy a 2pc seal motor,....

No retro-fit parts available,.... No market, damn few Stringers left around,....
 
bondo

the engine on bottom is one i had . one ontop is one i want to use . I've found that the coupler i have from old engine has 12 bolt holes 6 were used to fasten to flywheel the other 6 were empty , when i put the coupler to other crank without flywheel i can bolt on with other 6 holes . the flywheel i had center hole is to small wont go on crank , if i were to get other flywheel with larger hole my coupler would fit , will it work that way ?
 

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cardoctorlv31 said:
bondo

the engine on bottom is one i had . one ontop is one i want to use . I've found that the coupler i have from old engine has 12 bolt holes 6 were used to fasten to flywheel the other 6 were empty , when i put the coupler to other crank without flywheel i can bolt on with other 6 holes . the flywheel i had center hole is to small wont go on crank , if i were to get other flywheel with larger hole my coupler would fit , will it work that way ?
Click to expand...

Ayuh,.... Somebody has been there before you,... That's not original, at All,.....

You'll need the flywheel to match yer replacement motor,...
Pre-'87 is the 3, 1/4" larger bolt pattern, post-'86 is the 3" bolt pattern,....

If the splines in yer coupler are worn, ya might wanta replace it now,...
Either way, Grease the splines, so's they Don't wear out,...
 
You now need the early SBC flywheel..... the one that would have been OEM with the boat's original engine.
Also, you most likely need the one with the 168 tooth ring gear.

Once you have that, see if the coupler will work.
If not, see if a machine shop can re-work it..... but as Bill said, look closely at the female splines.


Edit:
If by chance you have the later 153 tooth flywheel for the 1 pc rear main seal crankshaft flange, I know a man who is looking for one.


.
 
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thank you guys for input ! im going to try flywheel and original coupler see what happens ,if coupler dont work i'll get the one hystat say's to use . ricardo i'm going to hold on to flywheel till i'm up and running . I will post a offering if i don't use . thanks and I'll post soon as i have update
 
Update I decided to use engine , here's what i've done so far .... First after finding that a 74 chevy blazer with a 350 manual trans had the exact 12" flywheel 154tooth , my old block had except it was made for 2 piece seal. My old coupler had 12 bolt holes and using the 6 holes that where not used on old setup it fit ... put new block in boat . I think the 2 piece seal crank is little longer than one piece and i might have to trim the shaft a 1/4 inch to allow plate to fit flush I'm not sure ? Anyone see anything wrong with trimming it ?
 
update for anyone who's run into same problem i did with 1 piece or 2 piece seal 350 chevy install . First most of the questions I've seen is for reverse of my install people wanting to install a 1 piece in place of a 2 piece seal engine , unknowing my oem engine was a 2 piece and had been replaced with a 1 piece . i bought the 2 piece block and was told by many people they did'nt make a coupler and it wont work . It worked for me with just a flywheel change nothing else . i thought i might have to cut the iterm shaft but it mounted perfect , So with my coupler shown in picture above and one of the 2 flywheels (one with 3"center or 3 1/2 center ) you can use both rear seal types . I wish I could give a part number of coupler but I couldn't find it the difference is one comes with 6 holes and one with 12 holes . After some gasket changes I was up and running the block was out of a old rv rebuilt . dropped a hei distributor in it and runs great !
 
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