Mercury V8 build with mustang cobra parts recipe?

[madmatic]

Since the Merc V8's are pretty close to the mustang cobra engine would it be out of the question to use existing builds as baseline data for modding the Mercury? The old cobra 32 valve 4.6l made 332hp at 6k which i suspect is right where the 300R is at. So if we used the same cam/head work combo as the article here http://www.mustangandfords.com/how-t...gine-upgrades/ Could we expect to have similar results? Using the mercury exhaust and intake manifold will probably yield lower hp numbers, but if only cams and head work gets the motor in 380-400hp range i suspect there would be a pretty big demand for it. I spoke with a local engine builder and we both agree'd that as long as the rotating assembly and block studs arent crap, a well put together 32valve 4.6l should be able to generate and live with around 450hp on premium pump fuel. If the prop-shaft can survive is a whole other issue.

[Dave S]

I thought the V8 merc was a new design.... not a carry over from a car motor??????

[madmatic]

The v8 is not a carry over from a car motor but they do share some core features

Similarities:
1) 4.6l
2) Dual over head cam
3) 4 valves per cylinder
4) intake port fuel injections (not direct)
5) closed loop EFI to monitor AFR
6) Aluminum heads
7) peak power is very close in stock production form
8) Emissions/mpg (both are limited by cams and electronics to provide clean high mpg motors )

Differences: other than the obvious MFG
1) Ford is a 90 degree block, Merc is a 60 degree block
2) intake configuration (Mercury has the advantage with lots of room to change the runners)
3) exhaust configuration (Ford has the advantage of long tube headers)
4) Cooling (Mercury has a huge advantage with an unlimited supply of cooling water)
5) unkown materials (we know how much a cobra engine can take before it bends a rod or vents the block, whats the Merc made out of?)

the way I see it, as long as there isn't an issue of reversion it is not impossible or all that hard to have a custom cam grind made by (insert favorite cam company here) and match the head flow numbers by (insert favorite machine shop here). A huge advantage for us is that there are thousands of hot rodded 4.6l mustang engines running around reliably that we can use for guidance. What sucks is the intake runners are plastic so any port matching would require either custom sheet metal runners or now that 3d printing is getting common I guess some one could print one?

[stoker2001]

IMO the Exh configuration being so limited under that cowling...

[JPEROG]

There is no question that with compression, cams and head work on a motor of this displacement that 400 plus h.p. will be achievable. Now the cost of electronics, programming and hardware mods will dictate how many get done. When you look at the cowl, it appears to be a "ziplock dry bag" so allowing some air has to be another path to examine.

Joe

[LakeFever]

The big difference between marine and auto engines is operating RPM dwell. In a car you run up the RPM quickly, and setlle in at a low cruise RPM usually 3000RPM max. To make big HP you have to move big air and auto camshafts have their events set to maximize this, but not for sustained RPM dwell that boats require. Boats typically are set up to cruise in the 4000+ RPM range so the camshaft selection and lobe in particular need to be tailored to suit extended higher RPM cruise without issue. Comp makes the HUC lobe which is a marine lobe and its not very exciting in my opinion. For a good boat motor based off a car engine your going to want a strong rotating assembly and use a mild marine cam set to cruise the RPM range you want and then boost it. A roots type SC would be my first choice for its instant torque and good reliability or if you want to go for th egusto and make BIG power?

Run turbos.

Or add cubic inches.


Remember HP numbers are only at a given RPM and in car motas this is in the 7000RPM range. The torque under the curve is where the real magic happens and a boat mota with a peak RPM of 5500 will not come close to making the peak numbers of a car engine, but could easilly surpass all the torque under the curve to redline if you combine the correct parts. Whatever hp it produces think of boost as doubling that for every 14lbs you push through. As you add boost, you will require substantially better fuel which means no marina gas.

Its all a compromise, its not so easy to make big power without big sacrifice

[Dave S]

NO magic flyin rugs??????

[PRE-Z06]

IMO the Exh configuration being so limited under that cowling...

I agree, 80mm throttle body on 250hp+ V8s should support considerably more power and short runners of the 300R will be best bet as long runners on other V8s will limit high rpm breathing. Moving the powerband up will lessen the amount of lowend torque the engine makes, so would think this will be easier on the propshaft as the extra power is going to be applied once moving.

Not sure what valve springs are used on the new Mercury V8, but Comp has a newer high lift Marine lobe...
HLO HYDRAULIC ROLLERS
The HLO is similar to the HUC on the opening side with increased stability and optimized shape over the nose for improved dynamics. Acceleration and ramp rates are optimized on opening and closing to give the best possible high RPM performance without noise or bounce. 8000RPM+ with light valve and high rate spring

[Motv18]

When did merc switch from gm to ford

thought Yamaha had ford cornered for four strokes twisting johnyrude’s nuts looking for parts.