07vbluestang

i recently purchased frpp whipple polished 550 hp. supercharger and am seaching for long tubes. will the 1 3/4" headers lower my boost? with the 3.25 pulley i should be around 12lbs. the lower the boost for me the better!!! or would 1 5/8" be o.k.? i plan on running the off-road h pipe!!

S197steve

Unless you have a forged block you best not try to run 12psi... otherwise that motor is going bye bye real quickly.

As for the long tubes, I recently talked to Brenspeed and they said that the 1 5/8" tubing is good for up to 600hp or so.

onederful100

the LT's will lower your boost 1-2 psi
i have a gen 1 whipple with a 3.5 pulley and only see 7 psi with BBK LT's (1 5/8) and o/r x pipe, i estimate i lost 2 psi
i know of someone with a gen 2 whipple 3.25 pulley, BBK LT's (1 5/8) and o/r x pipe, he only sees 10 psi.
agree with s197Steve, the 1 5/8 should be good untill bigger boost, but you could go with the 1 3/4

you should be ok with that pulley and stock block, but more depends on how you drive.
you could always change to a bigger pulley.

mygt500

Get the 1 3/4 LT's they lower boost pressure and increase hp at the same time....just makes sense overall and when you go with big boost and HP (which the mod bug will bite again) you wont have anymore restriction! (well less restriction anyway)

Boost is just a measure of restriction and less restriction can yield more HP at less psi.

Many people go by if your N/A get the 1 5/8...if your boosted get the 1 3/4...