4.3L Performance upgrade.

[Dave87]

Hi Ive got a 4.3L Merc with a 2bbl carb. If I decide to change it to a 4 bbl carb how much more performance would I expect to get out of it ? Any issues with doing this ? Any other recommendations ?

Also I read on here about torque shift propeller. After watching some videos it seems like it make sense as a product. I don't understand why it isn't being manufactured ? I know the foundry burnt down but it doesn't seem like a complicated process to start making them again...

Thanks

 

[Scott Danforth]

which one of the 7 generations of 4.3 do you have?

1985
1986-1987
1988-1991
1992-1995
1996-2000
2001-2006
2007-present

going from a non-vortec (12 bolt intake) to a vortec intake and heads while going from a 2 barrel to a 4 barrel, you pick up about 30-35hp

just going from a 2-barrel to a 4 barrel is about 15hp.

it isnt being manufactured because it was too complicated to keep the price point down.

 

[Dave87]

which one of the 7 generations of 4.3 do you have?

1985
1986-1987
1988-1991
1992-1995
1996-2000
2001-2006
2007-present

going from a non-vortec (12 bolt intake) to a vortec intake and heads while going from a 2 barrel to a 4 barrel, you pick up about 30-35hp

just going from a 2-barrel to a 4 barrel is about 15hp.

it isnt being manufactured because it was too complicated to keep the price point down.

Sorry I should have specified I have the 1988-1991 gen

 

[Bondo]

Also I read on here about torque shift propeller. After watching some videos it seems like it make sense as a product. I don't understand why it isn't being manufactured ? I know the foundry burnt down but it doesn't seem like a complicated process to start making them again...

Ayuh,...... Torque Shift props are in deep trouble,......

My links to a guy on the westcoast that bought out all of the remainin' bits, 'n pieces,...... are Dead,......

A retired shop teacher, Bob, I think,......

I've been runnin' one on my tinbarge with a 4.3LX / Alpha 1 set up,.....
11" pitch is Great for trollin' fishin',.....
Went to the heavy springs to hold the pitch low,.....
Goin' to over-trimmed for a second will cause it to shift into high pitch,....

With the recommend springs, Dropin' the throttle results in the tach, Peggin at 5 grand,.......
As the steerin' wheel is violently ripped from yer hands, while the barge goes from 2 mph,.................... to,.......................43 mph, rather briskly,......


The 4bbl. carb will get ya 25 hp, top rpms,....

 

[Scott Danforth]

With your non balance shaft motor, best bang would be vortec heads and the 4 barrel