When I swapped my 7.3 for the 6.9, I just kept the 7.3 wiring harness and GP's. Aside from a slight power reduction and slightly higher boost (ironic, huh?), there wasn't much difference.

 

Is there a aftermarket lift or level kit you'd recommend? Something to make it drive straighter down the road, and something to make parts more readily available.

 

That might be the theory, except that the intake tract on an IDI is really pretty good - remember, it's designed to get the most out of a N/A situation, no boost at all. That's why you have these nicely sculpted intake runners, vs the 7.3 PSD just has these flat channels.

What you /really/ get is a case where the turbo sizing factors in to the equasion; with factory turbos or Banks Sidewinder(and actually the same with my S360), you just plain can't make as much boost at 1200 as you can at 1600 which is still less than 2k. Simply because the more air flowing through the engine increases the turbine speed, which increases the boost. Yes, added fuel does help, but you simply aren't going to be making 10 psi of boost at 1200 RPM. 10 psi at 2200 RPM, however, is easy... which is why you end up with this curve where the higher the RPMs are, the more boost, the more fuel burned and the more torque made...
However, counter to this is that as the IP spins faster, it has a harder time providing enough fuel. This is why you tend to hit a "crossover" point around 2800 RPM where IP fueling drops while boost could increase, and you hit your peak HP and torque.

With a 6.9, or something where you artificially limit fuel(to avoid blowing gaskets), you'll find that the torque curve ends up a lot flatter and downward-trending... not because of the engine, but because that's simply the best the IP can push under those conditions.

This is why you'll see a different curve with a stock IP vs a 110cc, because you have limits of fueling instead of air.

I honestly don't think the valves/intake cylinder filling is going to be the limiting factor for any IDI - it's either going to be air supply(boost) or fuel.
(note: be aware that N/A connecting rods turn to taffy at around 450RWHP(probably 600 at the crank)... and yes, it's been done. With head studs, that's still fine, though, even at 45 PSI of boost.)


Two things here:
1. If the valve guides need to be redone, do it. If the guides are tight, just get rid of the seals. With a turbo, you don't /need/ any valve seals, and actually want as much lubrication as you can get. The reason is that you will have positive pressure in both the exhaust and intake manifolds, so instead of trying to suck oil through the guides, it will try to push air(exhaust or boost) /up/ the valve stem instead.
I've done it with no apparent oil usage or smoke.

2. If you replace the valves or have any machine work done, CHECK THE VALVE RECESSION. This is the distance from the bottom of the valve to the deck of the head with the valve closed. It must be in spec(too much is OK, too little... you'll destroy your new heads in short order).

 

Thabk you for the tech! Good points

 

A 6.uh-oh going 500 kilometers before failing? That's hard to swallow.

If anyone ever gives me a 6.0 powered truck I'm swapping in a slant-6.

 

I think if you studded it with arp 2000's, welded the heads to block then p-pump it, it would be good

 

That's about 300 miles....

We actually had a slant-6 in a truck. '76 D100 shortbed 3-on-the-tree. We parked it when the diff acted up, and bought an '83 F150. Thing sat in the driveway for about 10 years, and cranked on a fresh battery. I'm sure with fresh gas, it would've fired.

 

Not to mention our stuff's all paid for. Every mile we put on them we're money ahead. I'd be more than disgusted in making payments on a $60k dollar truck and having to make a $10k repair while paying it off.
Not a chance in Hell.

 

Exactly, that's why I think he's exaggerating...

I plan on getting one someday. Always have had great luck with the slant; had (have) them in cars and vans, but not a truck yet.

 

That's (not even) one tankful.....

 

And one gallon if it was a Cummins.....

 

my 66 W300 had 645,000 miles on the slant six when it lost compression,
i swapped a 64 273 into it and ran it another 4 years and 184,000 miles before the cab fell off the frame.

 

Then my mom isn't the only person in history to have killed a 225. She tried to drive her '74 Duster from Detroit to Ann Arbor with NO oil. Got just about to the Washtenaw County line when a rod put a hole in the block the size of your fist.

 

my little sister had a 63 valiant with the slanty that lost the oil pump. she drove it for 3 weeks with no oil pressure before trading it in on a new torino.
ford dealer gave her $500 on trade in for it. she only paid $250 for it 2 years earlier

 

Not me, man. I'm getting an '86 this weekend which will become my son's first truck in three years. I'm going to spend the next three years fixing it up for him. I love IDIs.