Weiand 177 on 489 - Carb Help
 

Good evening. I have a mild 520hp 489ci that I'd like to put my Weiand 177 on. I know the blower is a bit small for these cubes, but I'm only looking for a modest increase. My current pulleys should get me 3-4 lbs, and I always run 93 octane.

With my current Keith Eickert headers, I cannot run a wideband without it getting wet. I've tried extenders, etc. My wideband fails instantly. That said, I don't really have a way to measure afr other than looking at plugs. I have a Holley 850dp on the boat now, and I'd like to use the same carb. Carb is a 4781-2 with 80s front and rear and 6.5 pvs front and rear. Does anyone have a recommend place to start for jetting? I'd like to keep the pvs and will boost reference the carb.

Thank you,
Adam

IMO, Carb is too small. You really need a 1050.

Just plop down a factory 525sc 1050 and run it? I think they came with 98s all around.

​​​​​​Thank you,
Adam

What is your current static CR and Heads???

9:1, heads are iron GM rectangular port

The Hawk 525SC had an 850 and 174 Blower. When I Updated and went to 640HP Nickerson rebuilt my 850's and it dynoed perfect, I still run my 174's I believe they were kicked up up about 950 CFM.

Thanks! Yea I thought the 850 would be enough. 3-4lbs on a 520hp engine should make right around another ~100-130hp, so I'd be right in that ballpark. It's just frustrating since I cannot use my wideband and I really don't wanna blow this thing up haha.

Well your engine is making another 50-100hp that’s going into turning the blower.

It can work, but no one would recommend an 850 for a 700+ NA engine

It started as an 850.
Like I said in reply the carbs were sent to Nickerson and redone to around 950 CFM when we increased to 640 HP re-jetted, etc.

just a FYI however I bought some New pro systems Boost reference carbs that were built for 468/177 sc’s from an oso member. They were just 950’s that flowed like 841 I’m pretty certain. I realize you have a few more cubes however I’d bet you’ll be just fine. Been down the mercury 525 sc’s road with 4500/1050’s and pig fat. Good luck and frequent plug cks at various rpm’s as I’m sure you have planned. Not looking for any arguments just facts.

Thanks for the feedback everyone.

I reached out to Nickerson and it sounds like they can get my carb setup pretty well since they have a lot of experience with combos like this, so I'm going to go that route. Again, this I'm not looking for every last hp. This is going into my Formula 242LS. I just want to be able to turn a bigger prop for cruise and maybe tickle low 70s. Boat is doing 67mph now but only turning 5100, so I know there's more in the setup as is.

Where are you located? Just curious... my old 242 is floating around out there somewhere.

I'm in the Finger Lakes. I bought the boat as a basket case out of Michigan last winter.

A 525sc (or close to it will run in the low to just mid 70's. If you give it some more carburetor, you can probably get a little more out of it. I had a 454 with a 250 and twin Nickerson 950s in my 242 and it ran in the 80's. You'll really need hydraulic steering on that boat with anything approaching 70.

Thanks for the feedback! I did put external steering on it last month, so all good there. Gimbal is in good shape as well.

What prop did you run in yours? I'm thinking I should be around 650hp with 4lbs boost.

I dyno'd mine with a weak blower and made a touch under 600 at 3-4 lbs, 5800. 454, Dart heads, 525 EFI cam. The boat ran well but would quit around 5k. I rebuilt the blower and she would pull 56-5700 making about 7 lbs. We were spinning a 26P Bravo. I have a 28P labbed by BBlades that I never got to try, but I think the boat was running well with what it had.

Honestly, too much engine for the boat really. Mine was a sit-down and I never really felt comfortable running her at a good clip in rough water. With the power and how it came on, it was easy to get into trouble quick. Been there done that and got the t-shirt. I live right by the mouth of the Chesapeake so that's where I'd usually head out. It's pretty rough a lot of the time... fun with my 311 but not so much the 242. I will say the 242 with the new power was a lot of fun on the rivers surrounding the area though! Mine had a new transom, stringers, bulkhead and engine room floors.

Sounds like fun haha. I just got a set of bolsters for mine, but don't have them in yet. I just want to be able to go tag along with my buddy's on poker runs who have 100mph boats. If I could do a solid 75 I'd be pretty happy.

Your carb is big enough. Nickerson will get ur carb close to optimum. Here is a similar set up (850 com) that we dynoed at made almost 600 at 5500. 2.7 lbs boost
https://cimg7.ibsrv.net/gimg/www.off...b01ccac16.jpeg