How Much HP?????

ric · **Posted:** Mon Aug 11, 2014 2:18 pm

kd4pbs wrote:

Depending on where you are, you can defy the heck out of the game warden / boat police with loud exhaust all you want; he'll still write you a ticket if it's too loud.
I think you're on the right track for sure, and can build power with a small block. Just remember though that as others have written here, they won't last as long. There's a reason they put big blocks in the bilge to go over a certain amount of power... they'll do it all day long and barely break a sweat.

Take your stock vortec 350, slap in a 383 stroker crank, GM perfromance camshaft, edelbrock intake, Holley 600cfm marine carb. 350hp and 400lb torque that will run until your boat rots to the ground from old age. A drop in 383 stroker crankshaft is only $190 bucks
http://www.summitracing.com/parts/SCA-910375/

That's all this is:
http://www.chevrolet.com/performance/cr ... t-383.html

crossram · **Posted:** Mon Aug 11, 2014 7:14 pm

the small block will give you a better rpm range but there is nothing like the big block power. which ever you go with make sure you have enough carb . a 600cfm wont give you what you want. go with a 750 cfm carter or edelbrock

ric · **Posted:** Mon Aug 11, 2014 7:35 pm

With a 4800-5000 rpm redline a 600cfm will be more responsive than a 750 on an engine making 350hp. Vacuum secondary also, no mechanical secondary crap. Using a 750 on a 300hp engine will actually make it slower and you'll be really unhappy with it's low end performance.

High CFM's are for high RPMs. Run that 5.7 @ 6800 RPMs all day around a race track? Yeah. 750. A boat that cruises at 3200? No way man.

RichA · **Joined:** Wed Jun 25, 2014 12:37 pm **Posts:** 98

I think ric has this one right on the money. Too much carb is a classic way to lose low-end torque and an easy trip to unhappy idling, and both are things you certainly don't want on a boat!

bigdog347 · **Joined:** Mon Jul 28, 2014 11:10 am **Posts:** 12

maybe I'm missing something but why would I need anything more than 600cfm Holley marine 4 barrel. I don't plan to go over 6500rpm, and based one what others have said I may even keep it to less than 6000rpm. I'm using a 5.8l(351ci) engine this should be plenty of carb. is there a reason that this would be different in a boat than a car?

As far as the drive goes it does say SX Cobra on the trim cylinders.

I do plan on using marine parts when it comes to the carb, distributor, cap, wires, starter, alt. I don't want to have a fire!

bigdog347 · **Joined:** Mon Jul 28, 2014 11:10 am **Posts:** 12

looks like I posted my carb size response about 30 mins too late. (got distracted by the wife)

ric · **Posted:** Mon Aug 11, 2014 8:13 pm

HA, yeah. I called Holley a while ago to get recommendations on my 5.0 with a GM Performance camshaft and edelbrock intake with a goal of roughly 300hp. They told me with a max RPM of 5000 that a 450cfm 4bbl would be perfect.

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

The nice thing about Carter and to a lesser extent Quadrajet carbs is that they are effectively a CV design; they'll only flow what the engine requires. That's why one can find a Quadrajet even on a 4.3 liter V6. I know Holley makes some vacuum operated secondary carburetors, but my experience has been that the Carter and Quadrajet will deliver better fuel economy than even a properly tuned Holley.

ric · **Posted:** Tue Aug 12, 2014 12:19 pm

Find me a marine rated one

Cap'n Morgan · **Posted:** Tue Aug 12, 2014 1:05 pm

ric wrote:

Find me a marine rated one

http://www.nationalcarburetors.com/mari ... ester.aspx

ric · **Posted:** Tue Aug 12, 2014 1:22 pm

Bookmarked the crap put of that site!! WOW! Thanks!

bigdog347 · **Joined:** Mon Jul 28, 2014 11:10 am **Posts:** 12

ric wrote:

Bookmarked the crap put of that site!! WOW! Thanks!

X2

crossram · **Posted:** Tue Aug 12, 2014 11:02 pm

first post was wanted to get up 340 -360 hp. at that hp you will push up to 7000 rpms .run a smaller carb you will have better response get to higher rpm could starve for fuel use bigger carb re jet it . sure if you are only going to hit 300 hp a 625 cfm is the right carb
.

john55c · **Posted:** Wed Aug 13, 2014 6:35 am

Cap'n Morgan wrote:

ric wrote:

Find me a marine rated one

http://www.nationalcarburetors.com/mari ... ester.aspx

Had bad luck with their carbs. They sent me 2...both had issues and didn't work properly. I got frustrated and so for a little over $100 more, bought a NEW Edelbrock 1409 Performer Series Marine 600 CFM Carburetor. It has worked perfectly for 2 seasons so far.

http://www.smwebhead.com/phpBB3/viewtopic.php?f=5&t=10425&start=15

deafwish · **Posted:** Wed Aug 13, 2014 7:05 am

A have a SBC and the profile and specification of the '1666' cam suits a mild pleasure/ sport boat perfectly.
Safe as houses for wet exhausts and much more performance oriented when compared to OEM.
If it wasn't for my pre-Vortec heads, I would have fitted this cam ages ago. :cry:

http://www.crowcams.com.au/Portals/0/Ca ... ock-V8.pdf

www.iFourWinns.com

How Much HP?????

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