Okay, I never heard of such a thing either for the 6.5 (sorry). I've read on other threads that the major power limitation on the 6.5 is the heads... If this is the case, do high performance heads exist for the 6.5?

Indirect injection is the limiting factor - which , of course, is the heads.

You could try dishing the piston crowns, blocking off the pre-cup , modifying the head to take the longer 6.9\7.3 injectors.

Run pre-heaters, because a screw-in 90deg angle glowplug seems very un-doable.

But - you'd still have the uneven, unequal clamping forces around the cylinder, because of the odd head-bolt spacing.

Then you'd have the crumbling mains situation.

And the cast-iron crank situation.

And the small exhaust ports situation.

And the ..........but, you get my drift, right?

GMCTD

I have not looked at these heads up close, is it possible to add a stud where needed and drill the block for the same?

Also can a steel crank be obtained for this engine?

I don't want to just keep up to D/max's or P Strokes, i want to blow away the modified ones too... lol

Why not just repower it with a jet turbine ~10,000 ft.lb thrust or so. LOL
You wouldn't have to switch fuels.

GMCTD

I have not looked at these heads up close, is it possible to add a stud where needed and drill the block for the same?

Also can a steel crank be obtained for this engine?

I don't want to just keep up to D/max's or P Strokes, i want to blow away the modified ones too... lol
I would imagine anything is possible CR, but for the amount of $$ you'd spend..:eek: I think your money tree would be pruned to nothing by the time you were done...

I think you can get a 400HP 6.5 from the folks at Peninsular. I don't think I'd want one because the more power you pull out of given block the more you reduce it's life.

The exhaust port and the injector\glowplug area cause the odd bolt-stagger configuration.

Pen does offer various hi-perf 6.5's, even a twin-turbo, but they generally are for marine service, where the entire lake, or ocean, is available for cooling.

I would imagine anything is possible CR, but for the amount of $$ you'd spend.. I think your money tree would be pruned to nothing by the time you were done...

I have deep pockets when i want something. But if it would just blow up in 10 or 20k then i wouldn't do it.

But if it would just blow up in 10 or 20k then i wouldn't do it.

Oh, I believe it would, it's a 6.5 ;)

Seriously though, GMCTD has is right, cooling would be the largest concern in making more power than the 350HP mark. At 400 there were quite a few mods, mainly in a lower compression ratio (even lower than the 18:1) and a DB4 injection pump verses the DB2 mechanical.

At 400 there were quite a few mods, mainly in a lower compression ratio (even lower than the 18:1) and a DB4 injection pump verses the DB2 mechanical.I thought we already covered this....
THERE IS NO DB4 REPACEMENT PUMP FOR THE 6.5!!!!
Check Peninsular's site, you will see they removed their ad.

T D G

Oops my bad, I knew i saw that somewhere, what this "we" stuff, I'm new, could you ever forgive me?

I work at a fuel shop, 'we' buy lots of IP cores amongst other things ;)

GMCTD

After reviewing QM's head pics it appears to me that there is room to add a head bolt of smaller diameter where the spacing is weak as long as there are no cooling channels or oil channels there in either the head or block.

As you know these engines inside and out IMO are there any channels that will interfere? Adding a bolt or two should only help if it can be done, i know you will weaken the head/block slightly by drilling but won't a smaller bolt be better than no bolt there at all?

Those areas are water channels, internally.

A bolt boss must be solid to the depth of the hole to support the compressive axial and radial clamping forces.

The internal block casting must be designed and placed to provide minimal acceptable distortion to the adjacent cylinder wall and deck surface.

It is likely impossible - sorry, charlie!