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-   -   750 carb good for 500hp (https://www.offshoreonly.com/forums/general-q/264240-750-carb-good-500hp.html)

Mariah212Z 10-24-2011 08:29 AM

My Application
 
I currently have a 355 sb mild build 350 hp approx flywheel.

Replaced my stock Weber with a 1409 Edelbrock 1409. Direct bolt in replacement. Bought the calibration kit but did not need it. Ran better from starting to WOT. Did not have my GPS but with full tank of fuel and three on board, I can say it woke the motor up big time. I will post next time I am out on the water for comparison to stock carb. Did notice that the primary butterflies on the Edel were smaller than on the stock Weber Merc and the secondary blades were the same size.

IMO the larger 1410 750cfm would be adequate for 454 but anything larger in cubic inches would require a larger cfm. Edelbrock does not go higher than 750 for the marine segment. The Holley or BG would be the best option for larger displacement motors. IMO

SB 10-24-2011 11:02 AM


Originally Posted by Artate78 (Post 3534534)
Holley 800 part# R84017-1

That's one of those 4011 model carb's.....the one piece main body deal where the top comes off ......body is polished...etc,etc ???

I did not have good experiences with those models in the automobile end, therefore have never tried the marine versions. I do believe Holley stopped making those not too long after there debut. Never caught on.

I also have not had good experience with the 4175's (spreadbore) in either marine nor automobile either.

I like the conventional 4150's and 4160's that have metering blocks on both Primary and Secondary sides. Work much better and are much more flexible.

Artate78 10-24-2011 06:26 PM

Yes SB that's the one. Guess I should just brake down and buy one. Next question 750 or 800 ? Or I was just looking at a 830 holley 9381 how would that work ?
And do you really nead marine carb what's the difference?
I have 454 .030 over
Gm 290 heads had big valves installed intake an exhaust Bowls worked and runners worked
Bob m little over 600 lift cam hydraulic roller
9.2 to 1 CR
And going with performer rpm intake
EMI Thunder exhaust
If I left any thing out just ask I'll post it up

brivander 10-25-2011 03:05 PM


Originally Posted by Artate78 (Post 3535691)
Yes SB that's the one. Guess I should just brake down and buy one. Next question 750 or 800 ? Or I was just looking at a 830 holley 9381 how would that work ?
And do you really nead marine carb what's the difference?
I have 454 .030 over
Gm 290 heads had big valves installed intake an exhaust Bowls worked and runners worked
Bob m little over 600 lift cam hydraulic roller
9.2 to 1 CR
And going with performer rpm intake
EMI Thunder exhaust
If I left any thing out just ask I'll post it up

Make sure it's a marine carb...the answer is yes, there is a big difference. The marine carbs are designed to have any excess gas in the fuel bowls and vents, vented into the engine and not outside as in automotive carbs. It's a safety issue to prevent fires and explosions. ALWAYS marine, not automotive in a boat, especially if you want your insurance to cover anything in the unfortunate event of a fire...

EDIT: Oh and you said you were going with Performer RPM intake (maybe you already have it, not sure) -- check out Amazon -- they had the best prices by far when I was looking a few weeks back. Plus no tax in certain states and free shipping.

HaxbySpeed 10-25-2011 06:42 PM


Originally Posted by brivander (Post 3536396)
Make sure it's a marine carb...the answer is yes, there is a big difference. The marine carbs are designed to have any excess gas in the fuel bowls and vents, vented into the engine and not outside as in automotive carbs. It's a safety issue to prevent fires and explosions. ALWAYS marine, not automotive in a boat, especially if you want your insurance to cover anything in the unfortunate event of a fire..


You don't actually need the curved vent tubes, that was just something that Holley came up with. The carburetor tests for USCG compliance were written sometime in the early seventies and are easily passed by almost any modern carburetor. We do a lot of mechanical inspections and testing for local insurance companies and have never seen an issue with an aftermarket carb, or braided or push lock fuel hose which also aren't recognized as CG compliant..

Young Performance 10-25-2011 08:28 PM

Haxby,
The insurance adjuster has never mentioned anything about braided SS hoses on the fuel system? I always wondered about that since they are not CG approved. I ran into it a few times with building engines for boat builders. They all specified to NOT use SS braided hose on the fuel system. This was when I was selling and shipping an engine directly to the boat manufacturer. I don't use SS hose anyway, so no problem on my end. I just figured it was an issue since I have had several of them specifically mention it to me in the past. Thanks
Eddie

brivander 10-25-2011 08:46 PM


Originally Posted by HaxbySpeed (Post 3536534)
You don't actually need the curved vent tubes, that was just something that Holley came up with. The carburetor tests for USCG compliance were written sometime in the early seventies and are easily passed by almost any modern carburetor. We do a lot of mechanical inspections and testing for local insurance companies and have never seen an issue with an aftermarket carb, or braided or push lock fuel hose which also aren't recognized as CG compliant..

My Insurance company had me do a self-checklist, and if I answered NO to any of those questions they are not liable, it's BoatUS by the way, don't know offhand what company they went through and don't have the paperwork with me. No Coast Guard sticker no coverage, I had this conversation with them after I filled it out.

I'm not arguing on the safety of other systems and I agree some of the requirements are ancient, braided lines, blah blah blah etc. I just don't know why you'd risk it if you don't have too. I do know, you don't want gas in your bilge...to many of have seen what that leads to...

Either way good luck on this project Artate78, let me know if you are interested in that carb.

Mariah212Z 10-25-2011 09:33 PM


Originally Posted by brivander (Post 3536639)
My Insurance company had me do a self-checklist, and if I answered NO to any of those questions they are not liable, it's BoatUS by the way, don't know offhand what company they went through and don't have the paperwork with me. No Coast Guard sticker no coverage, I had this conversation with them after I filled it out.

I'm not arguing on the safety of other systems and I agree some of the requirements are ancient, braided lines, blah blah blah etc. I just don't know why you'd risk it if you don't have too. I do know, you don't want gas in your bilge...to many of have seen what that leads to...

Either way good luck on this project Artate78, let me know if you are interested in that carb.

+1 Use a Marine Carb CG approved for a boat.

This should not even be debated??

HaxbySpeed 10-25-2011 09:39 PM


Originally Posted by Young Performance (Post 3536621)
Haxby,
The insurance adjuster has never mentioned anything about braided SS hoses on the fuel system? I always wondered about that since they are not CG approved. I ran into it a few times with building engines for boat builders. They all specified to NOT use SS braided hose on the fuel system. This was when I was selling and shipping an engine directly to the boat manufacturer. I don't use SS hose anyway, so no problem on my end. I just figured it was an issue since I have had several of them specifically mention it to me in the past. Thanks
Eddie

If you're using a low quality hose that has permeability issues then it could be a problem. Any good quality SS hose or pushlock will exceed the requirements. Insurance adjusters can deny initial coverage if they feel like it and most insurance companies don't like to pay at the best of times. However, if they try to deny a claim based on a component not being CG approved then they would have to prove that it is what caused the damage and that it is inferior to the CG approved part. I'm not advocating using cheapo automotive parts and you need to use common sense when selecting your components but you're certainly not limited to Holley's "marine" line. I could understand why an oem wouldn't want to cause a problem with an end user getting insurance though.

That's cool that you've built engines for several of the boat manufacturers. Did someone order a new boat and specify your power, or was the builder just trying something different?
What kinda boats did they end up in? I always see Teague engines being tested in new boats but rarely see stuff from smaller independent builders. I think it would be cool to see more new boats tested with custom engines.

Young Performance 10-25-2011 10:43 PM


Originally Posted by HaxbySpeed (Post 3536683)
That's cool that you've built engines for several of the boat manufacturers. Did someone order a new boat and specify your power, or was the builder just trying something different?
What kinda boats did they end up in? I always see Teague engines being tested in new boats but rarely see stuff from smaller independent builders. I think it would be cool to see more new boats tested with custom engines.

I have done it both ways where a customer ordered a boat and specified my power and where the builder offered and recommended my power. For a while I was doing engines for Nortech. This was a few years ago when Merc didn't really have anything in between the 525 and the 1075. Potter was working for Nortech building the carb engines. If a customer wanted efi, Nortech would sell them my engines. I built quite a few for them. Once Merc added the 600,700, 850 etc., it made more sense for them to go that route on a daily basis. I had trouble keeping up, and certainly couldn't supply all of the engines to them that Merc does. I only build about 25 a year since they are all assembled by me and only me.
I've also done a few for Hustler and a couple others. I'm currently building them another pair for Hustler that's going in a 39 Rockit to be one of their Premiere boats in the Miami show. Should be a really cool boat with around 1150 hp a side.
I really enjoy working with the boat builders. I get to see the boats from start to finish. It pretty cool to see how different companies go about the same task in totally different ways. The end result is the same but they took 2 totally different paths to get there. All in all, a pretty neat deal.
Like I said, they were all adamant about not using SS braided hose. I've always used push-loc anyway. I have had them even mention that they would not get CG certification if I used SS braided hose on the fuel system. I'm not sure if that's true, that's why I was asking. I don't have much dealing with insurance companies and that's how I would like to keep it.:drink:
Eddie


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