gt40p flow numbers question

drewzx3

Active Member
Feb 7, 2004
411
1
28
Louisiana
Alright im thinking about buying some gt 40p heads and plan to run them with my mods below plus 24lb injectors. My goal is 275rwhp. I dont know anything about flow numbers so here they are below. Should I be able to reach my goal with these heads?

Valve Lift-----IN CFM----EX CFM------% of EX TO IN
.100"-----------65--------64------------82
.200"-----------121-------110-----------71
.300"-----------171-------105-----------72
.400"-----------199-------141-----------70
.450"-----------195-------138-----------68
.500"-----------196-------141-----------67
.550"-----------200-------141-----------67

Valve Sizes-----1.850"----1.550"
Test Pressure 28"
Test Bore 4.030"
Average EX to IN % .100"-.500"=71%

All test performed on a flow management 500.
 
I believe it was Grady who posted several power numbers with different setups. One of the better ones I believe was 296 HP and comparable torque with P heads, a cobra intake and an E cam, as well as exhaust upgrades like O/R h and flows or or some other decent muffler. There was probably also some tuning done but I think P heads are a VERY good alternative to some expensive aftermarket heads even in stock form. Have Thumper work them over and youll be really surprised at what "stock" heads can do.