SVT THIS

iTrader: (27)

Hey, I'm getting some used Patriot 5.3s with 2.02 and 1.57 Ferrea valves.
Gunnar told me I could send them in and pay to upgrade them to the 2.055 and 1.60 valves if I liked

Some people have told me that if I went with larger valves I would screw up my port velocity and lower my overall torque numbers. What do you all think? Here are the flow numbers for both valve sizes.

Intake Exhaust
Lift 2.02 1.57
.1 67 61
.2 133 108
.3 194 147
.4 242 183
.5 274 205
.55 290 213
.6 296 220

Intake Exhaust
Lift 2.055 1.60
.1 70 66
.2 149 113
.3 210 152
.4 251 189
.5 284 215
.55 293 225
.6 302 230

I'll be running all the mods in my sig plus a 228R cam. Should I go with the larger valves for a little bit more money, or should I stay with the smaller ones? VOTE and explain your reasons please.

Patrick G

iTrader: (14)

Hey, it's your money, but 2.055 valve typically require new seat and new seats require lots of bowl blending etc. If the heads flow as promised with the 2.02s, then keep them. You are taking a risk of getting a hogged-out head if they go to larger valves.

FWIW, I made the power in my signature with 2.02 valves.

JZ'sTA

iTrader: (23)

Stock valves even work very well on many combo's.
I would stick with what you have and invest the extra money elsewhere.

xfactor_pitbulls

iTrader: (16)

I agree, but the flow numbers with 2.02 valves are kinda weak. You should be closer to 200+ at .300 and 300 at .600. Thats kinda par for the course on a stage 2 LS1 head. A 2.05 valve does require a new seat, 2.04 is really pushing it, with limited seat contact area. As Pat said, you have to reblend the bowls and roll the short turn alittle wider into the seat to get the results. This is where a knowledgable hand LS1 head porter can add alot of value. You would really be better off just doing that, send the heads to a good shop and have them handfinished and have a competition valve job, if you just have a generic job now.

Brandon