How can you tell if it is a Walbro 255 from looking at it? TIA

 

walbro is stamped on the metal part i believe!

 

part# is stamped on the side
255 = gss315 or gss317
255hp = gss340, gss341, gss342

 

Whats the difference in the HP and the regular?

 

HP = high pressure

better for turbo setups because it requires the setup to run more fuel pressure

 

yup, essentially the HP can continue flowing at higher pressures. the regular starts dropping off quickly after 60psi

 

In the 300-350 whp range would the non HP be ok?

 

simple answer yes. technical answer...depends on the fuel pressure. basically as long as you arent running 30+ psi or using an fmu or something to increase the pressure drastically then the regular 255 is fine.

stock fuel pressure is 38psi + 12psi of boost = 50psi total fuel pressure. Both pumps are able to flow about 50 gallons/hour or 3150cc/min

 

won't be running high boost, and no FMU. Hondata S300, RC 750's

 

then either will work, the HP is only $10 more so might as well pick one up.

 

I already have it

 

this is some good info