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2bbl to 4bbl conversion on 43l

hbbutler

Member
I would love a little more pow

I would love a little more power out of my 4.3l 2005
alpha 1 . Am I wasting money with a 4bbl conversion ?
 
"Not with today's fuel pri

"Not with today's fuel prices since when you are just cruising, it should improve your engine's fuel consumption. About a $450-$550 DIY job using a reman. or aftermarket carb and merc. manifold. Look on EBAY.
Guy"
 
"...it's Good for about 25

"...it's Good for about 25/ 30hp"

True, but only at WOT. At cruising speeds it'll be the same.


Jeff"
 
"You could go to a 2" less

"You could go to a 2" less pitch prop. This would give you more jump out of the hole.
Also something like a High Five prop allows the prop to spin easier from a dead stop so that the engine can get up into a higher RPM power band, and this really helps performance.
If you are not hitting at least 3000 RPM with a WOT dead stop almost immediately, you are turning too much prop.
If it's top end speed you want, you need more power, and the power required will be the square of the increase in speed.
I had a 4 bbl Webber on my 1996 4.3LX Vortec and it ran pretty well. What hp is yours rated at?
Rod"
 
"Its stock rated a 190hp. It b

"Its stock rated a 190hp. It bumps the chip at 5000. Im WOT at 4600 now with the prop i have. If I get no improvement at midrange, then this is a change that i will pass on. But... I do love he sound of a quadrajet...."
 
"If I was you I would consider

"If I was you I would consider dropping 2" on prop pitch. This will get you out of the hole better, better skiing pull, and closer to 4900 RPM at WOT.
Then if you still want more you shud be able to find all the bolt on 4 bbl parts either on ebay or in a marine bone yard somewhere. Might take some research, but it will be out there somewhere. I think there are several used boat part places around that you could find easily doing a Google search.
Good luck on the project.
Rod"
 
"Definitely spend the money on

"Definitely spend the money on the 4bbl. I was able to get the 4bbl intake manifold and carb from a boneyard, and spent the money to have the carb rebuilt on the spot. I love mine and would do it over again any day of the week. Still get great gph , not much change from the 2bbl."
 
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