Looking for some head.....

[dlivewyer]

Info.:D. I need a set of stock heads for a '91 merc xr4 'fat block' part number 187893. Or, if you know what cc these heads are, that would be great. Thanks

[mach351]

Fat block will let you use any 2.5 head....I’d imagine somewhere in the 34-37cc range with that 3.375” bore would put you where you want to be. Should be able to use 2.5 head gaskets too....so you can fine tune your compression if you’re close with thin/thick gaskets.

[dlivewyer]

That good info, thanks. We're looking for about 125-130 lbs compression. From I've gathered so far, we were thinking a 32cc 2.5 head should put us close. I'd rather it be 130-135 than be below 120.

[Merc 2.5]

What is your compression now ? My 2.4 200 went from 120ish to 135ish with 33cc heads