I want to replace cracked log manifold with 4" center risers on CVZ

[Plugcheck]

        Your GF is willing to help, that is some fantastic news,  my wife is adamant about boats being just my thing.    As for being an expert, everyone started new at some point.   I have done a little interior work and trying to find a Consew 205 to handle bigger stuff, but I'm personally closer to apprentice level than master.  Big difference is working on your own stuff is rewarding in my opinion.   Since weather is working against you right now, I would consider doing some minor stuff on your Z that can be accomplished primarily indoors.  Seats and other interior items could be ready.  Maybe your dash needs some clean up, new gauges, or wiring and fuse updates.   Build a quick stand for your outdrive and you could have it cleaned up with new impeller ready to go on.  If your replacing the transom, then spend some time cleaning and painting the mounting plates.   Collect the correct hardware for assembly.  Maybe take a look over your trim pump and put a kit in it.  Having the stuff ready to go instead of stopping to order and collect supplies makes the project really move when the weather breaks. 

[Scott in nh]

        Your GF is willing to help, that is some fantastic news,  my wife is adamant about boats being just my thing.    As for being an expert, everyone started new at some point.   I have done a little interior work and trying to find a Consew 205 to handle bigger stuff, but I'm personally closer to apprentice level than master.  Big difference is working on your own stuff is rewarding in my opinion.   Since weather is working against you right now, I would consider doing some minor stuff on your Z that can be accomplished primarily indoors.  Seats and other interior items could be ready.  Maybe your dash needs some clean up, new gauges, or wiring and fuse updates.   Build a quick stand for your outdrive and you could have it cleaned up with new impeller ready to go on.  If your replacing the transom, then spend some time cleaning and painting the mounting plates.   Collect the correct hardware for assembly.  Maybe take a look over your trim pump and put a kit in it.  Having the stuff ready to go instead of stopping to order and collect supplies makes the project really move when the weather breaks.

Some of those I thought of, others (like servicing the outdrive) I hadn't!

Dash is in the boat, in the cold, but the motor, outdrive and interior are in the basement

[Scott in nh]

I guess I also should have asked if the performance improvement is worth the extra expense compared to replacing with the standard log type manifolds?

[Rosscoe]

In my opinion, if you have to replace the stock exhaust, it is worth going to center rise. Used logs with rear risers are not cheap and...they are used. Besides, center rise are supposed to flow better. I am sure its a modest amount but we'll take anything we can get, right? Probably the biggest gains would be seen of you can spring for some aluminium ones due to the large weight difference, but they do cost more. I bought 3" GLM iron center rise from Moore Performance. They are heavy, but....
I went with 3" because that is the size of my thru hull tips and had no interest in enlarging those.

[Scott in nh]

In my opinion, if you have to replace the stock exhaust, it is worth going to center rise. Used logs with rear risers are not cheap and...they are used. Besides, center rise are supposed to flow better. I am sure its a modest amount but we'll take anything we can get, right? Probably the biggest gains would be seen of you can spring for some aluminium ones due to the large weight difference, but they do cost more. I bought 3" GLM iron center rise from Moore Performance. They are heavy, but....
I went with 3" because that is the size of my thru hull tips and had no interest in enlarging those.

Nice looking motor!

My original thoughts mirror yours, but was curious what modest means.

Moore wants us to believe it is like putting headers on an car engine that had really restrictive cast logs - is it?

5 HP? 10 HP, 15 HP? on an otherwise stock 260?

[CVX Fever]

I bought 3" GLM iron center rise from Moore Performance. They are heavy, but....
I went with 3" because that is the size of my thru hull tips and had no interest in enlarging those.

Those GLM from Moore performance have individual exhaust runners which are supposed to perform better than the open plenum design of the stock MerCruiser stuff. How much added HP is a good question and probably depends of a number of things. Ole Red always ran those GLM's on the motors he built. Too bad he isn't around to give us his perspective.

[Scott in nh]

So the weather is still not cooperating, but I have been busy anyway.

I used a straightedge to check the mating surface for straightness and used a file to get it all flat.

Didn't really take that much - I would suspect that anybody who put GLM's on and had them leak probably bolted them on right out of the box.

[Glastronjohn18]

Lookn' good Scott. You shouldn't have any problem with clearance as your 4" risers are the same height as Mike's 3" ones. See pic below from GLM catalog.

[Scott in nh]

Lookn' good Scott. You shouldn't have any problem with clearance as your 4" risers are the same height as Mike's 3" ones. See pic below from GLM catalog.

That's good news! Thanks

[Plugcheck]

   My manifolds also required a little massaging to insure a good seal.  Typical when dealing in the aftermarket I suppose.

[Rosscoe]

I did not experience any leaking.

[Scott in nh]

I did not buy the kit with all of the hoses and mounts etc.,  nor did it come with any directions, but in looking at pictures it appears that I go from six exhaust cooling lines to four - correct?

If so it looks like I need to change my thermostat housing from 6 hoses for the exhaust to four?

From this, plus the two in the thermostat cover):

http://www.iboats.com/mall/partfinder/?cart_id=291081346&gd_grid_id=1863&gd_poid=109059&gd_row=13&session_id=092822404

To this:

http://www.iboats.com/mall/partfinder/?cart_id=291081346&gd_grid_id=1863&gd_poid=109060&gd_row=15&session_id=092822404

Is the above the correct part?

Then I should have one cooling line going to the riser and the other to the bottom of the manifold correct?
Does it matter if the bottom one attaches in the from or back?

FYI the manifolds shipped with two threaded openings in the bottom of the manifold and all of the openings in the riser capped.

Also, is there a way to remount the alternator without also moving the power steering pump or should I just get the kit?

http://mooreperformance.info/BracketsSB.html

EDIT: found GLM instruction manual online, helps a bunch, but still open to advice.

[Rosscoe]

My conversion was from an older 350 with a jet and the cooling hoses were different than with the center rise and had to change thermostat housings.
I'll look for a pic of which ones go where.

[Scott in nh]

So I have the alternator mounted to the head using a GLM adapter.

The power steering pump is mounted in the original spot.

You are right, a different thermostat housing with fewer hoses is required.

I bought one, but the outlet that goes to the PS cooler is on the wrong side.

Talking with the supplier, there is a way to move the outlet (the GLM part# with the outlet on the starboard side appears to be discontinued).

[Rosscoe]

I have no PS on this one.

[Scott in nh]

I have no PS on this one.

Looking at your picture, everything is the same, but the hose that goes down by your alternator is on the other side on mine.

That is the hose that also has the PS heat exchanger in it.

Fittings were just threaded in, so changing it over was easy.