When we initially built these and checked them I pulled all 4 risers and seen puddles of water in the manifolds on 3rd cylinder back on both banks. Now I see no water puddles, dampness, but do see droplets in the risers. Im sure some is sneaking by. I believe the reversion has to do with the firing order being that the 2-3 and 4-7 are swapped. Almost makes me want to order a custom ground cam in standard chevy firing order and just swap wires to correct coils and give it a test. Still possible being carbed.

Like a 2-1?

Look what I found. Harris Marine - new zealand. Full aluminum jacketed headers for 1600 usd. Hmmmmhttps://cimg2.ibsrv.net/gimg/www.off...b7819c0d1.jpeg

And a cad drawinghttps://cimg6.ibsrv.net/gimg/www.off...db4651f6d.jpeg

https://cimg6.ibsrv.net/gimg/www.off...b5c595f2b.jpeg

I was curious as well, so good to get an explanation.

My 272 Islander is really bow heavy with the helm probably a good 8” forward over the performance model. The ci manifolds and heads have been replaced with aluminum and it takes a LOT of power and prop to get the bow unstuck from the water. I never ran it with the stock ci stuff but the balance is definitely light in the stern.

The parameters corey is using us not requiring 93. It can easily be ran on 91. Just would need to be tuned to do so. Mine are 11:1 and running 91. 93 is kust used to maximize power. If you have why not use it

Tested boat today. Runs great. Slight problem. Lack of weight in rear will require reprop. Gets on plane very easy now. Once on plane you can be going straight and it will go whichever way it feels is the best way to crash. Did many drifts today. Ass end every time. Even was going straight at one point the it darted right so I corrected left and it decided to go right even more. Scariest ****ing boat ride ive ever had the pleasure of going on. Main areas its worst is 4k and below. Still starts to drift around 80. Have not pushed them yet as it is unsafe. Will be testing 4 blades next or props turning out. Highest rpm thus far is 5100 and climbing fast. Not the blower motors I had but fast none the less.

Sounds like you need to lower the X and shift the CG rear ward somehow. Is there anything up front you can take out? You’re now riding on a CG that’s moved so far forward it may be on the wrong side of your center or pressure on the hull. Combined with the stern being so much higher in the water now, you don’t have any drive or skeg in the water.

keep in mind that this boat also came from the factory as a single. Drives currently have a 1” spacer .5” above prop centerline. I had to have cutting edge add alot of cup last year to get 5 blades to grab for planing. Was slightly squirelly. With 4 blades was harder than hell to get on plane but hadled very well. No sliding. Minimal trim. Turned good. I always thought stern was heavy last year with minor squirelliness and 5 blades but would say I was wrong. I have to believe squirelliness was stern lift issue as it got worse. Front has 3 chairs and 6 lift jackets

In

Heres a quick video of here idling through a canyon on. Saguaro Lake AZ.

You need more women on the back bench. Problem solved and you are welcome. ;)

i know less about cats next to my knowing almost nothing about twins, but it does seem like your ass end is trying to climb up and swap places with the from.

If this was originally a single is there a pod down the center?

It may be worth filling up some 5g buckets of sand and moving them around until you find the sweet spot, but it does sound like you need deeper or different props.

My boat was originally a twin. What I was saying is you could also get it in a single, which is much less weight but still worked. I never take the wife or kids after heavy work just in case all hell breaks loose. Test test. Test. One other thing that is funny. Even at idle it has no control. Buddy said when on plane my boat looks flat. No bow rise. No stern rise. Just boring old flat

Started thing about the scenario. Idling in gear the boat does not go straight well either. I am thinking I have a possible air in steering case, which makes sense considering the boat drives like a willys jeep with a loose steering box

Checked steering play in off position. 8” when applying heavy pressure. Lol. Purged air. 1/16”. I think that explains the steering wherever it feels like. Found out drivers trim cylinder is not retracting fully as well. At least not consistently. Will rebuild them tomorrow. Did the other side last summer.

I believe that was the issue. Will update this weekend.

Not yet. Havent ran it since the initial run. Hopefully by friday

Ran boat today. Runs awesome. Still figuring out what she wants. Boat setup: full fuel (168 gallons, me snd friend, 6 lawn chairs, full cooler, bimini, 10 life jackets, umbrella with auger table, tools, extra set of props, 16 wetsounds speakers, 3 amps, 4 batteries. Throwing this out there just to confirm load. Having to relearn to drive her. Air in steering was issue last time. Straight as arrow now. Tested at saguaro lake 105 degrees running the dual plane manifolds. Ran cutting edge 5 blade 32 and cutting edge 4 blade 30. Started with 5 blade. Both props got her on plane, 5 blade did better planing. Both are labbed. Both slip. 5 blade pulls to 2k for moment then brakes loose and start backing off throttle then off to races. Bow way in air. 4 blade show slippage throughout planing pushing to 3500 back off and off to the races. Bow half as high. On my indicator my drives are level at 2. Ran 5 blade 32 and pushed it to the coals at trim 6-7 saw 82-83 at 4900. Did not try trimming down. Took break at beach and decided to try 4 blade 30. Remember boat would not plane at all with 4 blades last year, well it did twice out of 300 tries. Lol. Ran her around a bit getting the feel then laid the coals to her. Pulled 5k at 83. Hmmmm. Ran it again. Same thing at 6 trim level. Then I decided to trim down to 4. Gps shoots to 91 instantly. Then ran out of room. Was climbing steady though. The interesting part to me isnt the trimming. Its the fact that a 32 5 blade and 30 4 blade both hit 49-5k at same speeds at hang out there. Makes no sense. Other notes. Boat doesnt start packing air till I would say 80. Last year with blower motors I could feel it around 68-70. Now you cant feel it like last year . 4 blades seem to have much better bow control. Boat wants alot of trim to free up snd start moving. 4 blades feel peppier. Both props stable. Afr reading is showing 1.5 differential bank to bank with open spacer so one bank is 10.9 and other is 12.4 wot. Will be loosing them in trade for my single planes next which have much better fuel distribution and more kick in the ass above 4500. Two thing I wish would have happened. 1 I wish I would have trimmed down with 5 blades and 2 I wish I had more room today. Will be removing 1” spacers next along with single planes installed. On a side note I may be running her in havasu tommorrow which will give me the room to stretch her legs. Also bimini in layed down position in its bag was catching enough air to pick it up a foot off the engine cover. Never seen that when folded up and stowed.

Ill have a buddy video me

Just spoke to Auggie. Looks like the stars are aligning. He is going to be in Havasu next weekend. We are going to be doing some prop testing on the water. Just to clarify what I meant with the 32 and 30 I ran. Both props hit a wall at 5k but were doing same speeds. Should have been a 500 rpm differential. Me and auggie are coming to same conclusion. Needs to much trim to break boat free which is then dragging my imco nose cones. I believe the spacer being installed is complicating the issue. His plan is to bring some props with added cupping to hold the bow at less trim. It sound like he is going to bring 28 4 and 5 blades. Btw one other note. Oil temp. Hangs out at 190 all day long. See 210 wot. That is why I like the big 3x18 oil cooler with an oil thermostat. Doesnt get much more consistent than that. Oil pressure at hot idle always 40 even after wot.

I grew up in Needles CA. Hottest place in the US. Literally 125-130 normal. I got so used to it that I laughed in Iraq when I seen people whining about 110. Now I own garage door company in Phoenix. 115-120 outside. 140-160 inside where I work. Like working inside an easy bake oven. Lol.