Here is what I have, a set of stock LT-1 heads proffessionaly ported and port matched to the intake and was approximately $600 less.

2.08 Intake
1.60 Exhaust
28" test Pressure

Lift I/ E/ % of Ex to In
.100 87 66 76%
.200 152 125 82%
.300 209 158 76%
.400 248 176 71%
.500 271 185 68%
.600 276 191 69%
.700 285 198 69%
AVG 73%

How do these numbers compare to others?

 

Where did ya get those?
Those definitely flow well, I wish that was all there was to getting performance out of heads.

 

That's a fuggin huge intake valve on an LT1...

That being said these were my LE2 flow #'s with 2.00/1.56 valves

.2 139/109
.3 192/142
.4 241/170
.5 269/184
.6 274/195
.650 275/198

 

I no longer have an LT1, but heres what my Blackstone heads flowed when they had the 2.02/1.6 valves. Just throwing the numbers in for comparisons sake. Exhaust numbers were flowed with a pipe. Numbers were also backed on other benches, and when the intake valve was upped to 2.05 they picked up some cfm across the board. I am not sure if i have those flow sheets though.

.1 74/64
.2 147/118
.3 203/167
.4 249/197
.5 269/214
.6 284/225
.7 287/232

 

I didn't think you could get that big of valves in the stock LT1 castings. I was under the impression that 2.0/1.56 were about as big as you wanted to go. My heads were p&p and they flowed the numbers in my sig at .600 with no pipe.

 

LE2 flow #'s with 2.00/1.56 valves (GM LT1 castings)


(not currently installed on my car)

 

Kyle,

They only flowed 275cfm w a 2.055" valve on my bench.

Bret

 

Yeah i remember that now. Low and mid lift numbers were higher on your bench as well. No matter what a badass set of heads.

 

I was told by Larry Meaux that the biggest valve you could get in the intake of the lt1 style head was 2.055. My lt4 heads flowed 285cfm @ .650 .

96 T/A Old set-up: lt4 heads& lt1 motorsports custom grind cam 11.4@118.00 w/700r4 & 9" 3.89 3400lb 390rwhp/ 412ft-lb tq

New Set-up: 396 afr220's, comp cam, 250@.050, th400 470rwhp tuned by geoff @ thunderracing 3,187 w/me in it.