I have purchased a set of GT40 heads that have been ported and polished and have 1.94int and 1.6 exh valves. Here are the flow numbers:
Head Casting I / E Valve Lift Port Configuration

Size 0.1 0.2 0.3 0.4 0.5 0.6 0.7

GT-40 Cast Iron I 1.94 98 156 207 225 237 242
GT-40 Cast Iron E 1.6 127 155 178 195 203 203
I am installing 1.7 roller rockers and longtube headers. This is a 94 F350 with a 351W SD with an E04D.

Do I need mass air?

 

No, it's not necessary.

 

So my truck will run normal and all these mods will be ok. My 2nd pass at mods will include a better intake like a lightning model intake. What point will ineed to convert?

 

When the stock injectors are no longer sufficient, then you'll need a Tweecer or some such device to modify the computer tables. This could be done with an SD computer as well as a MAF version, but generally it's the MAF computers that have been studied by others and are compatible with the tuner software.

 

Ok when will my injectors need to be replaced then. I think stock truck injectors are 19lbs/hr.

 

What about a stock HO cam with 1.72 rockers. I have a stock HO cam in my garage.

 

The HO cam works well with speed density. You'll want to at least invest in a fuel pressure gauge so you can see if when the fuel pressure drops excessively and a wideband O2 to what the A/F ratios are with the go-fast parts.
You can use an adjustable fuel pressure regulator to increase the rail pressure at WOT or tuning software to increase the WOT fuel multipliers.

 

The 19lb injectors are good for 300hp, give or take, with standard fuel rail pressures. They can be stretched well beyond that with much higher pressures, such as with a blower and FMU, but it will shorten the injector lifespan. I'm guessing you are using the 351 truck intake at this point.. if so you probably won't exceed the capabilities of the 19 lbers, though you should keep an eye on the fuel pump via fuel pressure as Blurry indicated.

 

With better breathing heads and the 1.72 rockers on an HO cam, it's gonna run a bit lean with SD.

 

With an O2 sensor in the exhaust connected to an air/fuel meter, you can watch the WOT mixture and raise the fuel pressure if it runs too lean at higher rpms.

 

I'm putting a blower on my 5.0. It will be low psi, but I assume I should still step up to a little bigger injectors?

 

You can't just step up to bigger injectors and expect everything to be happy .
The stock computer is not programmed to handle positive intake air pressures. A blower on an naturally aspirated EFI motor requires an FMU to raise fuel pressure along with boost(this is how the motor gets the extra fuel it needs), and it needs a way to retard ignition with boost, or detonation will blow holes in the pistons in minutes.

 

What are the 351 roller cam specs? I have not been able to afford the 1.7 rockers yet. Here are the 2 cams I have access to:

Stock HO cam:
266/266 .444/.444 214/214 @.050" lift

Crane CompuCam 2031:
276/282 .468/.498 214/220 @.050"lift

I also have a Lunati cam that I am trying to get the specs for. Which cam would be be best with 1.6s or 1.7s so far?

 

The HO cam will definitly run on the stock computer, use it along with 1.7 rockers. That with the ported heads should make quite a bit more power over stock.

 

What about the crane cam without 1.7s?