I used an Edelbrock Pro-Flo years ago on a Monte SS. It was awesome, improved fuel economy 50%, improved idle, performance gain was way more than expected. The new units are so much better.

Mines getting the 550-531 super sniper 2x4 when it goes back together...Been sitting in a box waiting since last fall so I'll let ya know how it goes haha

540 with an 8-71

That's the models I'll be going with if I do it. Mine will be around 600ci and I think they're 1471s or 1271s.

I built a 509 w a proflow front mounted tb, afr 300 heads, tuned it with mefi3 on dyno, made 695 hp in a glory pull. Didn't make great torque with its short runner length (620 ish), did have great BSFCS past 6000 rpms. I then put the edelbrock operating system on it and fought to make 660 hp, it leaves ALOT to be desired with no knock sensor and NO WINDOWS based tuning software, terrible breakpoints, Id never use their operating system in a boat again. I do LOVE the intake though!

that intake would be nice for an under hatch twin turbo system.

Just my opinion, but I've run Edelbrock EFI and Holley EFI and there's no comparison in my experience. The Holley is vastly, vastly superior.

I just put a sniper on a 450hp 454 and it has been perfect. Fired immediately and fine tuning with the Holley software is super easy. No problems with the O2 sensor, But I recommend getting the innovate motorsports extension on amazon if you have a wet exhaust.
The only issue I had is the engine wanted to stall when dogging into gear, but messing with IAC settings fixed that.

What additional parts did you have to purchase for installation? Total cost for complete system? Thanks

I used a refurbished model 550-516 ($799) and the plug and play hyperspark distributor 565-301 ($249.95) and innovate motorsports bung extender 3729 ($65) and that's it. Started on the first try. Total system cost a little over $1100.

Thank you for sharing.

New boat is coming and not sure what to do. Put $$ into updating stock EFI or going with Sniper. Weighing my options and that really helps..