Volvo 4.3L Pre-Vortec to Vortec

[Dillusion808]

I have a '94 4.3L
It runs but has tons of hours so this winter I'm going to re-power. I only use this boat for short fishing trips and sand bar. I have a bigger one for the dark to dark trips so I can't see my self spending the money for a backet & outboards.

Since I'm going to re-power I was looking at getting a 08 and up 4.3L with the Vortec heads. Can I simply order a Vortec engine and call it a day? I do know some items I can swap over. Let me know if I'm missing anything or I need new parts instead of just swapping.

Carb - I have a 4BBL already
Intake Manifold - My understanding is I need to change this to the 8 bolt
Manifolds & Elbows - Can I re-use? I hope so I just got new ones less than 50 hours on them
Fuel Pump - I have an electric one hope its the same.
Fresh Water Cooling - I have the FWC kit hope I can swap this over
Bell Housing - Assuming the same
Waterpump - Getting a new one with motors anyways
Alternator and Power Steering - I'm assuming the same since its belt driven

The only cost difference is really any new parts I need to buy. Is there any real HP or MPG gains between the years?

 

[Scott Danforth]

Get a vortec marine long block, or rebuild yours and add vortec heads. Bolt your stuff on it

BTW, what do you mean by tons of hours? Most motors will go well over 4000 hours with maintenance

Vortec heads good for 20-30hp on the 4.3

 

[Dillusion808]

I don't know how much hours. The hour meter is stuck at 998 from the previous owner and I've put on at least 500. Going to replace it when I re-power

My bad for not really checking but when I bought the boat from the previous owner.
- Manifolds were shot
- Leg oil was old
- Props were stuck I had to cut um off

Once in a while after a full day out I'll notice some white smoke at the wash down while flushing. I can't tell from where. Oil is fine. Coolant is fine. I can never get it to happen at home while running it and it doesn't happen every trip at the wash down. The exhaust smell is also very strong. I'm assuming I'm running rich.

I live in Hawaii so no real winter I can go boating year round. I don't want too much downtime so I'm going to buy a reman block and swap everything over. Time permitting I should be able to get this done in less than a week. Then I can decide what to do with my old block later.

I just want to order everything I need at once because shipping takes time here and I hate waiting.

 

[Scott Danforth]

I would inspect your bores before spending money.

 

[Dillusion808]

Mechanic said it was good. My motor actually locked up previously because the manifolds were letting water in and he checked it out since that was a bit over my head.

But ever since then wife is always paranoid when I go out. Not saying I'm rich but the repower isn't much. Worth it to make her feel better.

I can swap external parts no problem.

 

[stresspoint]

you are on the ball with the parts that you posted that need swapping.

be aware the vortec has a alloy sump so dip stick will not fit from older V6.

later motor also runs a serpentine belt not a V belts so you may want to just check mounting points for brackets , harmonic balancer pully mounting points , etc , i am not sure if changes were made anywhere there, almost sure from memory all fitted up ok on my swap , however i had 2 complete set ups so i just used what was available in the stack .

 

[Scott Danforth]

I personally would pull your current motor, take it to a machine shop, rebuild the short block and just buy new vortec heads.

 

[stresspoint]

I personally would pull your current motor, take it to a machine shop, rebuild the short block and just buy new vortec heads.

+1 but i would just recon the original heads and be done with all stock.
been there done that building a frankin merk , yea it works well , but the effort is not really worth the result IMHO ,
swapping from flat tappet heads to roller rocker heads takes a lot of changes IE : push rods ,rocker arms , etc.

i still have a frankin merk 4.3 but all vortec , just different year engine bits + some machining works , ignition system you guys have to adhere to uscg regs , i don't so i can use what works best to get me some decent reliable HP from that little 4.3 .

 

[Lou C]

A 1994 should be a roller cam but no balance shaft, IIRC
Adding the Vortec heads shouldn't be difficult, I considered it but wanted to keep the manifold heated choke for my Quadrajet, which I could not do with the Vortec because it has no exhaust crossover. However if you're running an electric choke carb no issue there. The only other details with which I'm unfamiliar is push rod length and rocker arms, not sure when they switched over to roller rockers or if the old style rockers can be used with Vortec heads. Can't see why not but never fully researched it.
Come to think of it, didn't Rich Stephens do that? Put Vortec heads on a pre-Vortec motor?
Maybe search up his build.....
and if the OPs engine has closed cooling, I agree with Scott no reason not to have his original short block rebuilt.

 

[Scott Danforth]

The 4.3 was a roller cam motor in 1988. The 1993-1995 motors are balance shaft motors. The 1996 and later just got the vortec heads.

So the cheapest and easiest option for the OP is simply swap the heads and intake

 

[stresspoint]

my motor was flat tappet , when i swapped to all vortec stuff there were lots of changes to the valve train that i needed to address to set the lash and rocker ratios correctly , here is engine number

 

[stresspoint]

late edit : the early crankshaft does not fit a vortec block , the journals hit the casting webbing flywheels are also incompatible.

ha ha , i just found the pics , that jolted my memory of what a PIA it was to build that bitza motor .( picture journals is available if Op is still considering a swap.

one thing i will say is when i knew it was dead "or close to it " i held the throttle @ 6500 + rpm for about 2 mile to try to blow it and it was running strong the rest of the way to the ramp. .

 

[Dillusion808]

Rebuilding a motor is a bit more than I would take on. Guess I would have to see how much someone would charge but I think I can almost get a reman block for the same cost as paying someone to rebuild.

I can swap the motor myself. Pulled this one about 3 times already.