What is best carb for a crate 350?

[Aquadzac Captain]

Ok, I plan to get a new carb for my OMC marine 350. Right now it has a Rochester 4MV with divorced choke. Any great advice to swith to or upgrade to? Would like to improve performance and lesson the problems with air/fuel ratios? Thank you all for great posts!!

 

[Boomyal]

Re: What is best carb for a crate 350?

Try this<br /><br /> http://www.holley.com/HiOctn/ProdLine/Products/Marine/FMS/FMSFI/700-21.html

 

[f_inscreenname]

Re: What is best carb for a crate 350?

Edelbrock 650

 

[achris]

Re: What is best carb for a crate 350?

Would like to improve performance and lesson the problems with air/fuel ratios

Three choices. Injection, injection or injection.<br /><br />For that engine I'd run a Holley 950-52. 700cfm, 225-400hp. This is the marine version of the 950-22S. http://www.holley.com/HiOctn/ProdLine/Products/C950/C950TB/950-22S.html Bolts straight onto a 4bbl manifold. Costs a bit more than a carb but for performance and flexibility will more than pay for itself. <br /><br />Chris.........

 

[flashback]

Re: What is best carb for a crate 350?

I run the edelbrock 650 and love it, any more and you waste it.....good luck

 

[Aquadzac Captain]

Re: What is best carb for a crate 350?

Achris - would I love that Holley 950-52!! After reading the specs and install issues I might as well get a racing boat! WOW is that one sweet carb!!! <br /><br />Right now I am kind of leaning to the Edelbrock 650. Would it be SMART to change to an auto Choke than the Divorced one (what would that take if anyone knows) and would I need a kit to fit the manifold? Thanks all, you are great and glad your on the boater side of life. I dont feel so alone in these fun endevors.

 

[Aquadzac Captain]

Re: What is best carb for a crate 350?

Flashback..One last thought...does Edelbrock make a Marine 650 or am I splitting hairs? I only see 600 and 750.

 

[achris]

Re: What is best carb for a crate 350?

Aqua.....<br /><br />I am about to bin my Weber 4bbl (on a 4.3L) and put the Holley EFI 950-53 on. Will post when I'm done.<br /><br />Chris.........

 

[Dunaruna]

Re: What is best carb for a crate 350?

Chris,<br /><br />I'd also be interested in the results, did you find a supplier in Aust.?<br /><br />Aldo

 

[flashback]

Re: What is best carb for a crate 350?

Aqua, mine is actually called a Carter AFB, but I understand it is made by edlebrock...<br />Chris, how many rpms would a 4.3 need to turn to fully utilize 700 cubic feet per minute? I have seen a few posts where folks worked out the numbers for a 350 chevy, and it was well over 6000 rpm for it to actually use 750 cfm.

 

[f_inscreenname]

Re: What is best carb for a crate 350?

I have a Edelbrock 750 now but I think your right they only make a 600cfm not a 650cfm. If you don't have a “built” 350 the 600 will be fine. I also use a electric choke (came with it). In the past I have been guilty of either wiring open or removing all together the choke plate on many carbs. Most boating is done during the warm months and when they screwed up they weren't worth fixing. My Edelbrock has keep its choke for two years without any readjustment from its first setting. This year we had a chilly spring and it sure was nice to have it working right.

 

[Fishermark]

Re: What is best carb for a crate 350?

You can get a good deal on Edelbrock carbs, (which I prefer) at Summit racing. And yes, it is the marine version, not the automotive. You can get the 750 cfm for $285 ( here), or the 600 cfm for $295 (here)

 

[Aquadzac Captain]

Re: What is best carb for a crate 350?

Hmmm, cheaper for the 750 than the 600 cfm. What am I gaining with the 750 cfm than the 600 cfm? Can my 350 crate motor handle a 750 cfm or am I pushing the volume?

 

[f_inscreenname]

Re: What is best carb for a crate 350?

Depends on how much the motor is built up. If stock the 600 would be the way to go.

 

[Fishermark]

Re: What is best carb for a crate 350?

Yep - don't think of "bigger is better." If it isn't needed, (and probably isn't), then the smaller carb will actually perform better under most conditions.

 

[BinLurkin]

Re: What is best carb for a crate 350?

Fishermark. This sounds good $294.95 for a new carb. A rebuilt one is $500. Is a 4mv a Quadrajet? I contacted both Edelbrock & Summit & they say they don't have Marine carbs for Quadrajets. If it is a QJ, does the linkage or anything else have to be modified?

 

[bomar76]

Re: What is best carb for a crate 350?

The linked carbs are Square Bore, i.e. Weber AFB/ Carter clones. <br /><br />Quadrajunk carbs are spread bore.<br /><br />Your Rochester carb is a quadrajunk.

 

[Aquadzac Captain]

Re: What is best carb for a crate 350?

Ok, you all are selling me based on comments and what I read. I will go with a Edelbrock 600 cfm. Now the two questions are:<br /><br />1) I have divorced choke, can I go electric choke with what modifications or should I stick with standard divorced choke in the south?<br /><br />2) If I am changing from Rochester to Edelbrock 600 what modifications will I need for the manifold and linkage? Spread bore right on Rochester

 

[flashback]

Re: What is best carb for a crate 350?

Aqua, check this out, I don't have any experience with them so take it with a grain of salt http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33550&item=7909348732

 

[Fishermark]

Re: What is best carb for a crate 350?

If you have a spread bore carb, (like a qjet), you will probably need an adapter in order to put a square bore carb on - again, Summit sells them - adapter.<br /><br />And yes, the price is good. Better yet, the carb is simple and dependable - usually works perfect right out of the box without any adjustments.<br /><br />You can use the electric choke with no modifications. Just remember that if you leave the key on for long without the engine running, it will cause the choke to open. (Unless you wire it up through an oil pressure switch which would only give it power when the engine is actually running).