Fuel:
Both R&D and Conestoga make bigger Db2 pumps. From what I have seen on a dyno, the most you will see from heavily modded db2 is about 300/600. Conestoga builds the Super Moose and Omega Moose. I have seen one guy a while back who had the Super Moose and parallel twins and it seemed to run decently. I never heard any dyno numbers though with that. R&D dynoed a RD110 at 300/600.
R&D produces a Db4 that will get you over 400/800. They sell two models. The RD150 and RD180. With an RD180, that is what dynoed over 400hp and destroyed his bottom end. I think anything over 150cc of fuel and you will need a built bottom end. I will cover that later in this post.
If you want any additional fuel for an extreme build, you are looking at an 8 cylinder P-pump or a V-pump. That will be for more than 500hp or more extreme builds.
Turbo:
You can have one of the standard kits that were made for these engines. Iirc ATS made three different kits. They made the 085 which I believe was non-gated kit. They also made the 088 which was similar to the 085. And then there was the 093 which was wastegated. The 93-94 IDIT came with a turbo similar to the 093. A few differences were the turbine housing didn't flow as well and the downpipe was smashed between the engine and firewall. There were upgrades for that. Typ4 bought what was left of the inventory and sells it. R&D sells some upgrades as well. Typ4, Conestoga, and R&D all sell compressor wheel upgrades for those turbos as well. Maximum power with the standard units usually is just over 200hp. The compressor upgrades will help it flow more and will make a little bit more power.
Another turbo available is the Banks turbo. It is a wastegated turbo similar in size to the ATS 093. The last turbo built for these was the Hypermax turbo kit. These are non-gated turbos as well.
If you want more power than any of those turbos can provide, you are looking at either buying a kit from Conestoga or R&D or building something custom. The Conestoga kits use Garrett based turbos in their kits. R&D uses mostly Borg Warner. Other turbos can be adapted as well to their kits.
For an extreme build, you can do custom parallel turbos or compound turbos. Those would be for anything over 400hp but more preferably over 500hp depending on the size of the turbos.
Exhaust:
Most do at least a 3" downpipe. Even with a 3" dp the firewall will need to be knocked back. You could also do a 4" dp but that would require more firewall modification. Also another way to fix the firewall clearance issue would be to add a body lift instead of knocking the firewall back. As for the exhaust you can do either 3" or 4".
Intercooling:
ATS and Hypermax both sold a kit. Most people tend to do custom setups. You can either use a 7.3 PSD intercooler or 6.0 PSD intercooler. The 6.0 intercooler is a bit bigger but will take more work to fit it in. You can also find custom sized air-to-air intercoolors as well. Another route I have seen people use is getting an air-to-water intercooler from Frozen Boost. They have custom sizes and shapes for a decent price.
Engine Internals:
Cam:
There are quite a few cams available for the idi. R&D currently sells a Stage 1 which has been dynoed at around 350hp/700wtq and tends to peak around 1800rpm. The Stage 1 also bleeds a small amount of dynamic compression which is good with higher boost. R&D also has been testing a Stage 2 cam which was part of the setup when he dynoed over 400hp/800wtq. The cam drops dynamic compression a slight amount as well.
Another popular cam on the market is the Typ4 cam. It is an extremely popular cam for the setups running lower boost levels. It also was originally built for NA engines. I'm pretty sure it would make decent power with more fuel and boost. I've only seen mild builds with this cam though.
The last cam that I have seen in use is the J2 cam. The cam peaks around 2500 rpm but bleeds quite a bit dynamic compression which helps at higher boost levels. Of all the cams available, it has the biggest drop in dynamic compression but that is at a cost of some low end power. It does make up for it on the to end though. If an engine revved to 5k rpm that is where it would shine even more! The highest I have seen it dyno it around 350hp as well. In order to get this cam, you would have to get ahold of Justin Wheeler. He was the one who sold them.
Heads/Valves:
The heads flow pretty well. I have seen them flow tested and they actually flow better than a 4V 6.0 PSD head down low. They flowed worse with port work done on the intake side. The exhaust did benefit quite a bit from port work though. At a minimum, a port match should be done. Especially to the exhaust side.
As for valve work, a 3 or 5 angle valve grind is really good for flow. Inconel exhaust valves will help and are resistant to heat. You can also find them with a Stellite face which will make them a bit more resistant as well.
The 7.3 rocker arms are an upgrade over the 6.9 rockers. So that is a good upgrade. If you want more Harland-Sharpe sells roller rockers. They are pretty expensive but are good as far as long term wear goes plus there is less drag as well. R&D is currently working on some as well. They are about to be to the testing phase soon.
Lastly for valve train, upgrade the valve springs to 7.3 Powerstroke Comp 910 valve springs. They are cheap insurance and are a good upgrade.
Pistons/Rods:
For pistons we have either stock NA pistons or IDI turbo pistons. You can also get Total Seal gapless rings which helps immensely with blowby.
For rods, there are a few options you have NA rods which can only work with NA pistons. The NA rods have a 28mm wrist pin. There are also IDI turbo rods that have a 33mm wrist pin and seem to be a bit beefier.
There is also the possibility of narrowing 7.3 PSD rods to make them work. They need to be narrowed on the big end to make them fit our crankshaft. Additionally, iirc you would have to use 7.3 Powerstroke rod bearings in conjuction with those rods. The only way to make PSD rods work on a 6.9 would be to bush the wrist pins down to 28mm. This has not been tested for strength though. Overall, if someone uses PSD rods, they would be strong enough to up to 550hp.
From there you either have custom rods or billet Powerstroke rods. The Powerstroke rods would need the same treatment as the stock ones to work as well. Those rods would be good for extreme power levels.
Here is an interesting thread on using Powerstroke rods.
http://www.ford-trucks.com/forums/1...s-6-9-7-3-na-vs-idit-vs-94-00-psd-forged.html
Head Gaskets/ Head Studs:
You have a few choices for head gaskets. Victor Reinz and Felpro both make a really decent gasket for stock or moderate power levels. R&D with the help of a guy named Jan are working on producing a gasket upgrade. There will be one for standard compression and a set for lowering compression.
Here is the thread with some pictures of both sets. These will be tested in the future as well.
http://www.ford-trucks.com/forums/1393005-performance-head-gaskets.html
For head studs, there are the standard 6.9 and 7.3 studs. The guys that are pushing their engines harder are setting them at a higher torque setting. I have seen 120-140lb-ft.
If you want additional clamping force, you can have ARP make custom ARP2000 studs or even their top of the line ARP 625+ studs. That will cost quite a bit extra though. Iirc it cost $1500 to have a set made for a 6.9. I'm sure it would be a similar price for a 7.3.
Miscellaneous Engine Stuff:
R&D has a main stud girdle that helps with structural integrity and prevents the block from flexing.
Additionally with more power you will need better cooling. An aluminum radiator will help keep the engine cooler. That would be a good upgrade as well.
If I forgot anything, feel free to add on stuff!
