Carburetor and intake questions

[ab59]

Hey all, I am in the middle of a restore that includes a long block. I bought the boat with the bad engine. The Holley that is on the old engine ( 1988 OMC 5.7 ) is trashed. When I began a search for rebuild kits and or another Holley I was told that the carburetor does not belong on a boat at all and it was strongly recomended that I do not run it for any reason , or one like it. He said that the 80457-3 belongs on a car and not a boat.
So now the question becomes what carburetor do I run on a 1988 5.7 OMC . Looks like stock was a Quadrajet not a Holley which brings me to another problem of intake manifolds being different between the two carburetors. Which carburetor is best for the 1988 350 with a OMC Cobra setup ? The manifold on the old engine is a Weiland Stealth with no identifying numbers.




what do you guys think, should I find a Marine Holley for a 1988 OMC 5.7 or find another intake and Quadrajet carb setup for a 1988 OMC 5.7

 

[alldodge]

Nothing wrong with Holley or Edelbrock, either will work, just need to be marine.
Use the Edelbrock 1409 would be the easiest to install, and will work without much tuning. A 600 cfm Holley would also work

 

[ab59]

AllDodge--Another difference is that the froze up engine has high performance heads and I don't think that the new long block will have the same so will the intake that I have fit the stock heads ?? If so I think that I will just focus on finding a Holley made for a 1988 OMC 5.7. I am curious though , would the Edelbrock carb fit my intake manifold ?
thanks

 

[Scott Danforth]

correct the holley 80457-3 is set up for a car. came off a ford to be exact


as far as which carb is better. that is a preference. I grew up with Holley carbs. I think they are only slightly more complex than a ball-**** in a kohler toilet. easy to rebuild and easy to tune

if your motor is stock a 600 CFM will be fine. if your motor has had any performance work, you may need something a bit bigger.

for example, Volvo installed Holley 80159 carbs (715cfm 4-barrels) on their motors in the mid to late 80's due to the cam they changed to

BTW, the motor is a GM 350. OMC made the outdrive and exhaust manifolds and sourced the remaining marine electrics from variety of other vendors.

high performance heads? please elaborate. what are the casting numbers? most likely stock GM heads

looking at your intake, it is set up for a square-bore carb and not a spread bore. you do not have dual bolt holes for the generic one manifold fits all carbs. you may need to source a holley, or use an adapter if you want to run a 1409 (spread-bore)

 

[ab59]

Ok I bought a Holley 4010 600 CFM that is supposed to be for a sb Chevy marine application for 100 bucks on a popular auction site. Suppose to be new or rebuilt but at that price I'll take either . I have heard bad things about this model but after some investigation it came down to floats so if there is a problem I will put new floats in it.
Scott Danforth- I usually link the 5.7 with the OMC and Cobra so there is less confusion as to what engine and application I am talking about since there are several different engines and or parts that could be in the mix.
Getting to be a whole lotta pieces around here , hope I can remember where they all go . At least the deck is back in the boat now all I have to do is rivet it in and give it a coat of resin. Next is carpet , for some reason my wife does not like a roll of 8 1/2' x 25 ' sitting in the hallway of the house. Imagine that. lol

 

[jimmbo]

A 600cfm carb is more than big enough for a 5.7, even at 5000 rpm the secondaires will be less than 1/2 open. Your non-marine Holley is a Squarebore and so is your intake

 

[Gunsanddaisys]

Just a hint, any marinized Holley has float vent tube that are bent back towards the carb throats. If the vents stuck straight up, no matter what, the carb isn't a marine carb.

 

[ab59]

yep Gunsanddaisys I kinda noticed that once some one clued me into the fact that the one on the blown engine was for a car and I looked up what the difference between them was and noticed the little u turn tubes on the marine style.

 

[ab59]

here is a kinda late question but valid just the same. I noticed that fuel pumps are being sold , not to match the engine but the carburetor and or stern drive maker and the price is double and or triple of what a standard fuel pump costs. Should I buy a fuel pump that is for the carburetor ( that sounds really odd ) , the engine size or the out drive maker ??? more than just a little unsure as to what to use here.

 

[alldodge]

You can use any fuel pump so long as its marine qualified. It does not matter if its A, B or C company nor from one drive manufacture or another, it just has to fix and supply fuel between 3-7 psi, or can be regulated down to that level

 

[ab59]

thanks ALLDodge , the way some of these parts are advertised can be more than just a little confusing sometimes.