If it's a new build, I wouldn't start the engine with the aid of starting fluid. You'll be rebuilding another engine.

What Griff said. I believe there is a thread on here about epoxying the bottom something or another (technical jargon) to stop this.

I'd be more worried about the timing vs a fat quadrajet. Do SBC Vortec heads like less timing like the BBC Vortec?

I meant carb cleaner. Don't know if it makes a difference or not, please let me know! I certainly don't want to damage the new build.

Ayuh,..... If yer gonna splash Anything into the carb to prime it,....

Use Gasoline,.....

Well the carb ended up needing to be rebuilt. Timing and advance were set properly. No more hard start, backfiring, choking off idle, etc.. The boat runs very strong now and I'm pretty happy with this new build.

Factory 350 260hp that came in the boat got me 48MPH GPS.

New (rebuilt) 350 with vortec heads, aluminum intake, xtreme marine cam - 57MPH GPS!!

A 9 mph gain is huge. You probably added 100-140hp over what you had.
Old engine was probably tired so I'm betting you're in the 350-375hp range now.
Better keep some $$ set aside for an Alpha drive. You're pushing the limit for an Alpha.

Also what rpm are you running at top speed?? that cam states its from 1300 to 5500 rpm and if Griff hp guess is correct, you may be able to get into the low 60s with the right prop.

I'm only seeing 4500 RPM currently trimmed out at WOT. I have a Mercury Vengeance 21P Prop. Is it safe to turn a factory (rebuilt) bottom end and Alpha one to that range? What pitch prop would get me there? I'm VERY interested in seeing what top speed might look like with this build. I'd imagine another 1000 RPM and peak power of that cam would put me well into the 60's!

Thoughts?

What ratio is the drive... Something seems off to me. My 22 foot tub is less efficient that the scarab as it is heavier and has a deeper V. GRanted I have a 454 but uts the 310 hp efi mpi. I am right about 60 with a 23 mirage at 4700 rpm. You should be winding a lot higher than 4500 with a smaller diameter 21p prop.

Where on the drive can I find the gear ratio? The boat is in the driveway, I will go and check now. I agree, it's suspicious that I can't get it to turn more than 4500...