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smokediver
02-22-2004, 07:28 PM
I just put a new 4 bbl on my 4.3 . it is a vortec engine that had a 2bbl.. when I advance the throttle there is a little hesitation around 2000 rpm but it isnt too bad . at 3/4 throttle it is great ! at full throttle it seems to bog down and i have to back off.. i am very pleased with the extra speed.. i picked up about 400 rpm's.. it is an edelbrock 600cfm carb and i put in the kit that they recommended for my engine size ... any guesses ?

Speed-Racer
02-22-2004, 08:54 PM
Smokediver,

That's awesome, I can't offer any help, but have you GPS'd the boat before and after the modifcation? (or what where the speedo readings) I Was wondering what the speed difference really is...between a 2b and 4b setup.

MOP
02-22-2004, 10:11 PM
Post the model and numbers off the carb, there are a few real good carb guys that should pop in with the right ideas. My stab would be the secondaries coming in, when?

smokediver
02-23-2004, 05:48 AM
brandon, around 4 mph. I was turning a little less than 4700 now 5100 and into the limiter .I am sure that the aluminium edelbrock manifold would have produced more power but it didnt have the bronze inserts so I went with the cast iron instead.The manifold cost 160.00 and the carb was 279.00 . new flame arrestor was 85.00 . I have a 25 laser2 my ratio is 1.84 .. Mop , it is an edelbrock model 1409 . I am sure the secondaries kick in at 3500 ... thanks in advance..

Speed-Racer
02-23-2004, 06:14 PM
Smoke diver,

WOW! Your running too close to the rev limiter for me and even 5,000 I think is tight :rolleyes: unless the bow lift is down..... We tried a prop that got us up to 5,000 and when in rough water we had to back off the throttle, of course we had a lot of bow lift and therefore more chance to hit the limiter.


Thanks for the MPH info.

Hope everything works out!

BigGrizzly
02-23-2004, 09:50 PM
Carb is too big

smokediver
02-23-2004, 11:37 PM
600 cfm is too big .. that is why I installed jets/metering rods /step up springthat edelbrock designed for the 4.3 application .

rickrsbro
02-24-2004, 07:24 AM
if the carb came with the jetting chart, try stiffer springs, smaller jets and bigger rods. in that order. if that doesn't work, throw it in the lake and see if it floats. :cool:

my edelbrock was not an 'out of the box' experience. i dislike that carbs transition performance and will go back to a holley asap.

mikev
02-24-2004, 01:23 PM
i put the same carb on my 4.3 with the jetting kit and it runs great. if it bogs at wide open replace your fuel filter and check that your float level is correct sounds like it is running out of fuel. also play with your idle mixture screws mine will hesitate off idle if they are not adjsted correctly.

smokediver
02-24-2004, 07:06 PM
thanks for the info... i will give it a try and see what happens.. :cistineb:

sparepartz
02-24-2004, 07:33 PM
600 cfm is too big for a v6. a 450 or 500 cfm holley, used on older 302 marine apps is a much better choice. marine engines seem to like smaller carbs, maybe because of smaller venturi that keeps up velosity of the air/fuel mixture,and that makes torque,and boats love torque!! also check timing because you had to pull the distributor and could have accidentially retarded timing and since you changed carbs you did not notice the change in the idle speed, just a thought.