JL3100

I've found it interesting in the 6+ hours I've tried searching for information on ported 799 heads, I have yet to see someone who had existing 799's they took off to get ported. Seems like all I see is ls1 guys buying 5.3 heads and making obvious power.

Has anyone takin their 799's off and can vouche for a power increase that's worth $1300? I'm about to just swing for the fences and by a set of promaxx's with 2.08 valves and cross my fingers....

Thanks!

Slow05CC

iTrader: (1)

The 799 & 243 are basically the same head. People port the 243 ( LS6 ) heads all the time.

Depending upon what 5.3 you have you may want to mill them some to gain a bit in compression. Once ported the head will flow very well. On a DD 5.3 truck I wouldnt go too wild on valve size! Also larger valves can cause some PTV clearance issues, and/or shrouding in the small 5.3 bore.

See below for some flow charts:

LS6 Stock ( 2.00 / 1.55 )
Lift Intake Exhaust
.200 126 108
.300 184 143
.400 224 163
.500 251 176
.600 257 183


LS6 2.5 Texas Speed CNC ( 2.02 / 1.575 )
Lift Intake Exhaust
.200 147 114
.300 209 152
.400 258 191
.500 294 207
.600 316 226

Vortec350ss

iTrader: (20)

You can make great power with the ported 799. I take them over a ported 5.3 (706 or 862) head any day.