solas amita to quicksilver 5

ric · **Posted:** Fri Jul 18, 2014 11:36 pm

350cfm on a 4.3 that doesn't see over 5k rpms? Nope, perfect.

CFM is key on a car because they're revving to 6000 rpms. We're not. You don't need 600cfm until you're making 320-350hp on a 5.7. When I spoke with Holley to put the plan together to get 300hp out of my vortec 5.0 they told me to use their 450cfm vacuum secondary 4bbl for best fuel economy and to get my power goals.

Walt · **Posted:** Sat Jul 19, 2014 8:49 am

ric wrote:

350cfm on a 4.3 that doesn't see over 5k rpms? Nope, perfect.

CFM is key on a car because they're revving to 6000 rpms. We're not. You don't need 600cfm until you're making 320-350hp on a 5.7. When I spoke with Holley to put the plan together to get 300hp out of my vortec 5.0 they told me to use their 450cfm vacuum secondary 4bbl for best fuel economy and to get my power goals.

WTF????? I've never seen a 302 with less than a 500, and even then only on 2bbl.

A 500cfm is about perfect for a 4bbl 4.3, as my last boat had. I have difficulty believing someone did all that work to a motor, and didn't have the decency to put a 4bbl intake/carb on it. Shame on them! 600cfm is about perfect for a 302 (5.0L). Doing the math a 5.0 needs about 660cfm at around 6000 RPM (I know, a bit much for our use but use that as a guide).

Jdpber · **Posted:** Sat Jul 19, 2014 2:37 pm

I have the solution to solve your speed issues. Bravo 1 mated to a merc 525 EFI. Power, economy, speed. Boom problem solved. I expect to see installed by end of month.

deafwish · **Posted:** Sat Jul 19, 2014 8:24 pm

Remember that a 500cfm 2BBL will not flow the same as a 500cfm 4BBL - The scaling is different.
A good thread to read:
http://forums.iboats.com/forum/engine-r ... -gl-vortec

97BRO27 · **Posted:** Mon Jul 21, 2014 1:29 pm

deafwish wrote:

Remember that a 500cfm 2BBL will not flow the same as a 500cfm 4BBL - The scaling is different.
A good thread to read:
http://forums.iboats.com/forum/engine-r ... -gl-vortec

That I do know, but that was a great read. lots of info to digest.

So was out last weekend again and the river gremlins keep getting me. did a little tweaking on the carb and hit 48mph with the 4blade 19 pitch alum. at 4700 rpms when my steering was just gone.
Talk about an "oh shit" feeling, had to get towed in my some awesome passer by's. Found out the next morning that the big brass nut that connects the cable end to the steering actuator came loose. threaded it back on and tightened it back up, all good, topped off the power steering fluid just a tad low and back to nice and smooth movement.

never did put the 5 blade on to check after the carb adjustments but I'm really thinking of just doing the 4barrel swap. at the min. putting a 500 cfm 2 barrel on. that way I can keep current intake manifold. I really feel as if it is choked out on the top rpm range. looking back even adjusting the carb a bit I didn't gain from my previous posts.

been trying to cross reference the carb numbers and all i can find is the rebuild kit. doesn't specify CFM. anybody have a resource that can look up the numbers?

Holley 6R 3250 B
80312-1
2366

97BRO27 · **Posted:** Mon Jul 21, 2014 1:36 pm

Jdpber wrote:

I have the solution to solve your speed issues. Bravo 1 mated to a merc 525 EFI. Power, economy, speed. Boom problem solved. I expect to see installed by end of month.

Really don't have a speed issue per say, would just like to get everything out of this engine as it was built.

deafwish · **Posted:** Mon Jul 21, 2014 4:04 pm

I also struggled with your Holley part #!
Can you take some photos of the number & also down the throat?

kd4pbs · **Joined:** Thu Sep 05, 2013 10:34 am **Posts:** 350

Sounds like a 2300 series carburetor. Could be either 350 or 500 CFM. I guess one would have to measure the butterflies to find out, because some Google-Fu surely comes up blank.

97BRO27 · **Posted:** Tue Jul 22, 2014 9:19 am

well at least I feel better that you guys struggled also. I'm pretty sure it is the factory 2brl. I will try to measure the butterflies and let you know what that is, have kids soccer, and a baseball game tonight. might have to wait till tomorrow to get the time.

thanks everyone.

ric · **Posted:** Tue Jul 22, 2014 10:13 am

The 5.0 in my boat has a 1bbl about 3in in diameter. I would say somewhere in the 300cfm range. Amazing it makes 220hp and pushes my turd to 45mph

kd4pbs · **Joined:** Thu Sep 05, 2013 10:34 am **Posts:** 350

A 3" TB would be somewhere more around 750 CFM unless you don't open it all the way.

97BRO27 · **Posted:** Tue Jul 22, 2014 2:30 pm

yeah I can't imagine a 300cfm on a 5.0. as stated earlier I have a 650 on my 5.8 351windsor that is mostly stock except for a slightly heavier cam. used to run great till that tree jumped out in front of me..

97BRO27 · **Posted:** Tue Jul 22, 2014 4:17 pm

ok so i just sat on hold for 45 min. with holley and finally got someone on the line. It is officially a 350 cfm. He suggested bumping up to the 600cfm 4 barrel. Now the search for the right combo. Thinking edelbrock performer with the holley 600cfm. Going to run about 600 bucks, or just swap the 350 for a 500 2barrel and save the trouble of changing the intake... eitherway going to enjoy the summer as it runs fine and the summer is short.

But that would answer the question of why I can't hit the numbers that I've been looking for. Can't believe that the previous owner spent all that money to build up the motor to choke it out right from the start... His parts and labor list for the engine rebuild was 4k. probably worried about gas consumption..lol

97BRO27 · **Posted:** Tue Jul 22, 2014 4:17 pm

might try and snap this up...maybe leery about buying a used carb.

http://www.ebay.com/itm/251592668387?ss ... 1423.l2649

what do you think?

Walt · **Posted:** Tue Jul 22, 2014 8:29 pm

Either way is definitely an improvement.... just make sure it's a MARINE carb.

www.iFourWinns.com

solas amita to quicksilver 5

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