Intake manifold question???
Everyone will say Fast 90/92 hands down.
My experience says the following. Here's my flow testing, driving and dyno testing experience with the two intakes - it's rpm dependant and depends on what sort engine you want to build.
My small cam LS1 383 make more power with the 90mm LS6 than the Fast 90. 3 whp more peak. The 90mm LS6 was up ~3 to 8 wtq for the whole curve and a few whp forth whole curve. My 383 LS1 is whats called a tow truck motor here on LS1Tech. It's near perfect as a nice fun mild mannered daily driver engine. Peak hp 6,000 rpm shift at 6,500 rpm. The 90mm LS6 drove better (basically stock) vs the Fast 90 which drove good.
A higher reving, peak hp at 6,500 rpm or higher and shift at 7,000 rpm big cam engine would do better with the Fast 90 due tote Fast 90's bigger runners.
The Fast 90/92 has a bigger intake runner it will max out with porting ~ 280 to 285 cfm the 90mm LS6 has a smaller intake runner. It's possible to get 270 to 275 cfm out of the LS6 intake runner.
Lingenfelter always get more hp with the Fast 90/92 vs the 90mm LS6 on their big revving LS7's. Back in the day (2007-2008) when I had a long talk with Lingenfelter with Fast was usually up 10 -15 whp on the 427's.
If you have to buy an LS6 and then mod it get the Fast 90/92 instead.
If you want to shift above 6,500 rpm say 6,800 rpm to 7,000 rpm + get the Fast 90/92.
If you have an LS6 and like the street happy tow truck motor type of build - it's an excellent choice in my experience.
Best wishes with your project.
My experience says the following. Here's my flow testing, driving and dyno testing experience with the two intakes - it's rpm dependant and depends on what sort engine you want to build.
My small cam LS1 383 make more power with the 90mm LS6 than the Fast 90. 3 whp more peak. The 90mm LS6 was up ~3 to 8 wtq for the whole curve and a few whp forth whole curve. My 383 LS1 is whats called a tow truck motor here on LS1Tech. It's near perfect as a nice fun mild mannered daily driver engine. Peak hp 6,000 rpm shift at 6,500 rpm. The 90mm LS6 drove better (basically stock) vs the Fast 90 which drove good.
A higher reving, peak hp at 6,500 rpm or higher and shift at 7,000 rpm big cam engine would do better with the Fast 90 due tote Fast 90's bigger runners.
The Fast 90/92 has a bigger intake runner it will max out with porting ~ 280 to 285 cfm the 90mm LS6 has a smaller intake runner. It's possible to get 270 to 275 cfm out of the LS6 intake runner.
Lingenfelter always get more hp with the Fast 90/92 vs the 90mm LS6 on their big revving LS7's. Back in the day (2007-2008) when I had a long talk with Lingenfelter with Fast was usually up 10 -15 whp on the 427's.
If you have to buy an LS6 and then mod it get the Fast 90/92 instead.
If you want to shift above 6,500 rpm say 6,800 rpm to 7,000 rpm + get the Fast 90/92.
If you have an LS6 and like the street happy tow truck motor type of build - it's an excellent choice in my experience.
Best wishes with your project.
I've got an '04 LS6 long block swapped '98 Z28. I originally installed an SLP LS6 intake that was modified for my '98's EGR system. I put down 385 RWHP with that intake. I swapped over to a FAST 92 w/NW 92mm TB and dynoed at 400.1 RHWP. However, that combo cost me a little over $1K. Some would argue that's a bit much for a 15 RWHP gain, but my goal was 400 RWHP without LT headers. I just have Hooker shorty headers and stocks cats.
