04goatman

I have a 04 gto & it has ls6 intake manifold. Is it worth spending anywhere from $450-$550 for a used fast 78mm intake ? How much addt'l horse power will i agin at the wheels with the fast intake ? I have a mild cam 222/224 566/568 112 LSA & 2800 stall torque converter,stainless work off road headers, tune currently 363 RWHP.currently i have ported & polished the throttle body.

RareBreed0295

iTrader: (35)

Im not sure about thr Fast 78 but the Fast 90mm shows average gains of 15+rwhp over the Ls6. Read the stickies. The Fast works best if you are going to do a H/C setup.

Tainted

iTrader: (9)

the FAST 90 is best, but the 78 will have gains over the LS6

52172

iTrader: (2)

you will pick up around 8 rwhp if you have a ported TB.

Urban Legend

iTrader: (5)

I wouldn't bother with the 78 mm.

bryan04h

iTrader: (2)

if you arn't going with the 90 setup, i wouldn't bother

sciff5

iTrader: (1)

Seeing as the LS6 intakes are going for pretty big money for a used factory manifold the 78 may be worth it if you can find a ecent deal on them. I have seen them go for 500$ which is only another hundred - hundred fifty over the ls6

radkon

iTrader: (2)

I got the FAST 78 on my GTO (mods in sig). I picked up 10 RWHP but lost 7 lb/ft of torque (I think my tune was pooched and will be redynoing in the spring). I bought the intake for $400 and sold the LS6 for $350 here so for $50 it was certainly worth it to me. I also didn't have to buy a 90 mm TB which saved about $400. If you do some research you'll see that the RWHP difference between the 78 and 90 is about 3~5 HP total (based on Tony Mamo's research).

04goatman

So with my current mods: listed top post, Is it safe to say With the ported factory throttle body which i have now I may gain 5 -7 rear wheel horse power with 78 mm fast throttle body after tune ?

radkon

iTrader: (2)

I would say thats a pretty safe estimate.

Soul TKR

iTrader: (4)

where do you get a fast for $400!!!!?

JPH

iTrader: (2)

My advise to you is, if you do a FAST 78 intake,(which you will like) make sure you use a 78mm t/b as well. Trust me, you will see a huge difference between a ported stock t/b VS like a WILSON 78mm piece. I know from experience.

radkon

iTrader: (2)

For sale section!

Brads LS1 02Z

iTrader: (16)

going from a ls6 to a fast 78mm probably would be a waste.... if you had a ls1 intake manifold that would be a different story...

bryan04h

iTrader: (2)

i still say if it isn't a 90/90 setup i wouldn't bother, how often are you going to come across a fast 78 setup for $400...

1970judge

iTrader: (12)

The 78 mm you will see gains over what you have now, but a 90mm setup you can take with you to another build down the road. As it stands i don't see you using a 90mm manifold to its full potential BUT, you will still see an increase in power and times. To answer it directly is it worth it yes, but is a 90mm a better investment, of course.

-Marcus