Will these heads support a 408?
Thread Starter
TECH Enthusiast
Joined: Dec 2002
Posts: 698
Likes: 0
From: Fort Worth
Will these heads support a 408? I got these heads ported by a local guy. He is just starting LS1 heads but, is the best out there for LT1. Anyway, he said he kept the runners small to keep the velocity up. Explaining to me that more velocity at lower rpm means more torque. Since, I have a truck that is just fine with me.
6.0 heads
Lift Int. Exh.
---- ---- ----
0.050 36 30
0.100 65 58
0.150 104 86
0.200 143 112
0.250 182 135
0.300 210 152
0.350 234 170
0.400 254 183
0.450 274 191
0.500 290 200
0.550 298 206
0.600 304 209
After 0.600 it levels off. These numbers are with used stock valves and no pipes or tricks, I was standing right beside him while he was doing it. The midrange numbers are perfect, I think. I will change the valves. What do you guys think?
6.0 heads
Lift Int. Exh.
---- ---- ----
0.050 36 30
0.100 65 58
0.150 104 86
0.200 143 112
0.250 182 135
0.300 210 152
0.350 234 170
0.400 254 183
0.450 274 191
0.500 290 200
0.550 298 206
0.600 304 209
After 0.600 it levels off. These numbers are with used stock valves and no pipes or tricks, I was standing right beside him while he was doing it. The midrange numbers are perfect, I think. I will change the valves. What do you guys think?
TECH Enthusiast
Joined: Feb 2004
Posts: 743
Likes: 0
From: Foley, Alabama-southern Alabama
Do you know if he put a backcut on the valves ,I bet he did if he,s done a lot of H.P. head work?Those # look real good to me especially if he kept the port volume small,your .300 to .500 #s look great. Are those LS-1 heads or 6.0 truck heads and how much did he charge to do the port work??What casting # are they?
Thread Starter
TECH Enthusiast
Joined: Dec 2002
Posts: 698
Likes: 0
From: Fort Worth
The valve are just used stock valves he had laying around, no work done on the valves. I will have some larger better valves installed. He chargered $400 to port the heads.
Last edited by StupidFast; Mar 14, 2004 at 10:22 AM.
