I know the stock 5.0 fuel pump is not big enough for a 5.0 HO. How about the stock '87 TC pump? I've got a nearly new one on the wall in the garage...
Hell, the stock TC pump isn't sufficient for a stock TC. Step up and get what you need. Who want's to drop the tank again.
John
The stock TC pump is exact same as the HO 5.0 pump(88lph)... They are fine for a basically stock HO or STOCK 2.3T...
Problem with the TC is because after 80-90K miles, the pump often couldn't keep up with pressure requirement under boost(55psi)... I've replaced at least a half dozen in TCs that were failing at around 100K mi, but never seen a 5.0 HO that pump wasn't still fine at same mileage(no doubt it'd hiccup in a boost application)... I'd guess even the high output versions will begin to fail at higher mileage...
Do you know what the free flow rating is for that pump?
88 Lph
Then what's the "loaded" flow?
That depends upon the fuel rail pressure......Most pums EFI pumps are rated @30-40. As the pressure upstream increases (increasing the effective size of the fuel injectors it has the exact opposite effect upon a fuel pump.
An Example:
(http://i280.photobucket.com/albums/kk191/V8Demon/Car%20Tech/flowtests.gif)
The amount of voltage seen at the pump will have an effect upon flow as well. The Kenne Bell Boost-a-Pump increases the voltage at the fuel pump thereby increasing flow. Cougar 5.0 used one in the past with good results.
If by free flow rating, you mean how much will it flow with close to zero pressure -- that depends as well.
Walbro rates the 255 pumps as flowing 285 @ 0 and 255 @ 40...
Yes, by "free flowing", I mean zero line pressure (above atmospheric).
If I had to veture an estimate......100-105 LPH.