Jeremiah

iTrader: (5)

At what point does the Fast 90 combo become a restriction? Im running a 422 with AFR 225's, a Fast 90 combo and a 259/267@50 on a 115lsa cam.
It made 550/504 Rwhp/Tq but peaked at just 6300 Rpm. I have been told the Fast 90 is a restriction at this point and I would be better off with a Beck sheet metal piece or simmilar.

Any thoughts?

studderin

iTrader: (28)

yup. a good port job to feed the heads better would be beneficial on that setup.

BigB02Z28

Please don't flame this response... I am new and not 100% knowing...

But... From a 422 and a cam of that size... Arn't those peak numbers a little low? Especially with AFR heads?

Arn't there people with 346 and 242ish cam's with peak numbers around 470/480? But not that great under the curve?

If the Fast 90/90 is bottle-necking that engine, shouldn't he see a big gain by going to a sheet-metal intake.

I am by no means insulting Jeremiahs build, so please don't take this the wrong way...

But I am just trying to recall peak numbers I see people posting with in various forums.

Hope no one takes offense to that, Its very easy to take the above in the wrong direction, but I can't figure out a better way to re-word it at 1am... =]

Jeremiah

iTrader: (5)

No offens taken,

I have heard I could expect 40-60 more HP on the top end with a loss on the lower end. Being a six speed car and the way I drive I dont think I will miss the low end loss.

I know there are some NA 346 cars making those kind of numbers but the average I have seen with a 242ish cams are in the 420 Rwhp range give or take.

I had hoped for more power from my set up but over all I am very pleased.
As of right now im leaning to the Beck set up but I would still like to hear some more thoughts/oppinions.

Thanks guys!

Jeremiah

iTrader: (5)

That was my first thought, I have seen threads where some have gained approx. 15 HP from a simple port job on the Fast.

RE AND CHERYL

iTrader: (31)

That would sound a bit low to me. I personally know of a LS1 Vette with LTs, Patriot heads, and a small MTI stealth II cam that made 417 RWHP.

Either way, in your case that FAST 90 is a restriction.

Re'

Mike@ZMS

iTrader: (10)

Get the beck setup and then make a charitable contribution to my car with the donation of your FAST 90/90 setup! It will be the best thing you will have ever done for another human being and will immediatly qualify you for a free pass into heaven. How could you go wrong???

But yeah, your motor is big enough to want to breathe enough for the FAST to be a restriction. Another option might actually be to convert a LS carb manifold (like the Edelbrock intake) to a FI intake with a 90* elbow off of the carb plate so you can mount an very large TB, then have the intake drilled for the injectors. A friend of mine did this with great success and very impressive power gains on his wifes race car (12secSS on here)

Good luck with it though, and for what its worth, you may end up with similar gains with the carb intake over the sheetmetal piece, but it would cost you a lot less.

Then again, theres always Harrop, if you can find one!

Jeremiah

iTrader: (5)

A friend had The Harrop on his car and had quite a bit of fitment/tuning/air cleaner issues that never got completely worked out. He ended up going back to the Fast 90 set up. I also didnt like how the Harrop cluttered the entire engine bay and was a real pain to work on and around. Simply bolting it onto the engine was a royal pain.

IMO the Beck is a much more practical piece and far better suited to my needs. It also doesnt require a custom air intake, its far easier to work on/around and has zero moving parts to give you problems down the road.

I have heard once you get the Harrop dialed in its a killer set up and some have shown killer gains with it. I just dont think its a practicle piece for an F-body.

I havnt completely ruled out the possibility of a carbed style intake. It looks like more people like the GMPP intake over the Edelbrock piece and it fits under the cowl plenum better than the victor.