Newbie question on old chrysler 135HP LU

Hi, my name is Jeff and i just took possession of an old 74 Invader tri hull with a chrysler 135. Motor runs good but lower unit was torn apart by PO. Its a 2 piece by the way. I cant seem to find parts for this thing, specifically a water pump kit. Anyone know where i can find this> Im also having no luck on finding a complete used lower unit for the motor. Hope someone can chime in and help a newbie out or point me in the right direction, hope i didn't get my self into trouble with this old thing...lol. Thanks in advance!

-Jeff

Somewhere on the motor is a sticker.It will have a model# and serial#Need that to make sure your getting the right parts.
Parts are available sometimes on e-bay or Craigslist.
Look for a complete motor about the same year and same HP.J

Some Mercury outboard dealers will be able to help you, not all of them.------------------Chrysler = US Marine = Force which was owned lastly by Brunswick = Mercury Marine.-----Should not be hard to find parts and there is always " Flea-bay "

Thanks for the replies. The Model is 1357HA and Serial # is 5329. I found boats.net and found a selection on chrysler 135HP parts, but they dont list this model# or anything before 1976. I read somewhere that most of the "parts" are the same around these years between the 115-135hp engines. i hope someone can confirm. heres the link to what im looking at.

Cheers

http://www.boats.net/parts/search/Merc2/Chrysler/135 (1976)/1358BD/GEAR HOUSING/parts.html

Maybe I did not give enuff information----------------------Look it up on ----------mercruiserparts.com-----------I believe your motor is listed.Just take the time to look.

74-75 Yes most of the parts are the same.
Impeller-18-3085 part# Can be bought on this site.About 27$
Look around boats .net they only go to a 76 but it's the same as yours.
Google Chrysler and add outboard and or motors and you will get more sites.
i boats has a Force/chrysler forum too.The guys there have different place they buy from.J