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.