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camshaft for v6 4.3 and sterndrive

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frenchy greg

New member
hallo

i m greg , living in france near the lac leman , so sorry for my english .

my new boat is
*a windy 22 sport with a broken v8 5.7 , 220cv . i will rebuild this engine later (vortec , head camshaft 383 , edelbrock intake , hei , etc ) . but for this year , il will be impossible
*the stern drive is a volvo , sx c2 , ratio : 1.51



in my other boat (17 feet) i have :
*a nice v6 4.3 , gl , 190cv , 2 bbl carb , vortec (8 bolt intake) coming origanely with a sx drive
*the stern drive is a 280 power trim (elephant ears , i think you call il like that) , ratio 1.61 , prop 15x19 3 blades
nb : to connect the 4.3 with the 280 , i had to change the flywheel and modify starter . but i still have the flywheel , coupler , etc coming from sx .

it works nice and runs fast but a tree go down on my boat :mad:


first , i m going to upgrade the 4.3 with a 4 bbl carb (coming from the broken 350) and an used vortec intake 4bbl (8 bolts) . i m wating for the part

my questions =

- like , i don t have the boat under my eyes , i dont remenber one thing :
for the valves , a full stock 4.3 is it = flat tapped ou roller or something else ?????

- after carb evolution , i would like to change the camshaft for a one a little bit more agressive . not a race boat but increase horse power and torque to fit the 22 shell

what will be the good choice (comp cams , edelbrock , etc)

- once , the 4.3 will be in the windy : what will be the good choice for stern drive :

** change the ratio : i m not familiar with sx drive , can i just change the lower part of the stern drive (like i ve done : change it a 2.15 for 1.61) .
nb: for maximum speed , volvo says 14x23 and 1.85 ratio

** change the prop for this year ?


thank you

greg
 
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frenchy greg said:
my new boat is a windy 22 sport with a broken v8 5.7 , 220cv . i will rebuild this engine later (vortec , head camshaft 383 , edelbrock intake , hei , etc ) .
If you custom build a 6.3L SBC (aka 383 cu in SBC) DO NOT use the GM Full Dished pistons, and DO NOT use the long connecting rods!!!!!!

but for this year , il will be impossible
*the stern drive is a volvo , sx c2 , ratio : 1.51

in my other boat (17 feet) i have :
*a nice v6 4.3 , gl , 190cv , 2 bbl carb , vortec (8 bolt intake) coming origanely with a sx drive
*the stern drive is a 280 power trim (elephant ears , i think you call il like that) , ratio 1.61 , prop 15x19 3 blades
nb : to connect the 4.3 with the 280 , i had to change the flywheel and modify starter . but i still have the flywheel , coupler , etc coming from sx .


OK..... you will first want to know that the earlier 4.3L Engine and the 280 drive are of the AQ series family.
The later SX drive is a Gimbal suspension drive.
The transom cut-out for the SX is much smaller than the AQ series is.
In order to mount the 280 components, the cut-out will require rework (enlargement).

The 280 w/ power trim would be around 1980 or so. If this is a later model, it may be a 290, of which is also power trim.


Also, the AQ series drive coupler is an all steel Borg Warner unit.
The Gimbal system SX coupler is a rubber hub unit.
These will not interchange between the two drive types!

it works nice and runs fast but a tree go down on my boat :mad:


first , i m going to upgrade the 4.3 with a 4 bbl carb (coming from the broken 350) and an used vortec intake 4bbl (8 bolts) . i m wating for the part
Calculations show that a 4.3L engine operating @ 4,000 RPM requires only 306.713 CFM at 100% VE.
In other words, the 4 bl carburetor may be more than what this engine requires.


my questions =

- like , i don t have the boat under my eyes , i dont remenber one thing :
for the valves , a full stock 4.3 is it = flat tapped ou roller or something else ?????
You may want to remove the intake manifold and verify.

- after carb evolution , i would like to change the camshaft for a one a little bit more agressive . not a race boat but increase horse power and torque to fit the 22 shell

what will be the good choice (comp cams , edelbrock , etc)
Contact a reputable camshaft company and ask this question. Make sure that it is understood that this is for a Marine application.

- once , the 4.3 will be in the windy : what will be the good choice for stern drive :
In a small hull and with the AQ series drive, the 1.61:1 reduction will work.

** change the ratio : i m not familiar with sx drive , can i just change the lower part of the stern drive (like i ve done : change it a 2.15 for 1.61) .
nb: for maximum speed , volvo says 14x23 and 1.85 ratio
For a small hull, see above.

** change the prop for this year ?
For a propeller selection, the only accurate method is to use the WOT RPM test.
See your OEM information for the suggested WOT RPM.
NOTE: this is a TEST RPM only.


i will run thru hull exhaust 2 x 90mm diameter
The OEM exhaust system outlet will be 95mm.


thank you

greg
Click to expand...
 
hallo , happy new year

thanks for the answers

in my old boat every thing is already connected since 9 years : 4.3 (2001) , flywheel from aq175, coupler from aq175 , modified starter to accepte the number ot teeth on the fly wheel .
the 4.3 (2001) when i ve bought it , had every thing for sx assembly . i ve kept everything (rubber coupler , fly wheek , etc) . it s why , it s be easy to install in my new boat with the sx drive .


which carb must i look ??? the carb coming out from the v8 is a quadrajet



i ve already contacy comp cams , crane , eytc . waiting for answers .
jegs gives me a reference , but it works with roller . it s why i ve asked my question roller or flat.


in the windy : it s not a aq assembly . it s a sx ! and the problem is the ratio : 1.51 .
when reading volvo tech pages for the 4.3+sx = they say for maximum speed ratio must be 1.85.
i understand for the prop .


on a sx : if i change only the lower part , is it ok to have the right ratio ?
(i ve found here in france a very cheap lower part with the 1.85 ratio )
 
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