Chris5k

Hi guys, i recently built a 350 with vortec heads, airgap intake, demon 650 and comp xe268.. the exhaust is hooker shorties and hooker y-pipe. if im not mistaken the y-pipe reduces to 2.5 inches, and the rest of my exhaust is also 2.5, and there is a flowmaster out back with stock tail pipes.. my question is, will there be any real gain going from this to a 3" cat back? would there be any gain going any larger than 3"? I really have been considering the hooker cat back, but i dont want to spend any $$ without seeing a difference right now.. thanks in advance

JamesC

iTrader: (5)

This from the sticky:

<B>Hooker 2055.</B> Prolly one of the best headers available. 50-state legal. The best part of this header is the y-pipe. 2.5 " mandrel bent, into a 3" pipe. Primaries are large 1 5/8 18g. Problems: collector gets down really small. It could be modified to flow more however. Avg price: </B>$365.00 for the set</B>

I'm very happy with the following set-up: Hooker 2055's (Jeg's 520-2055). Catco high-flow converter (Summit CTO-9118). Hooker catback (Summit HOK-16823HKR). Three inch Y, cat, catback.

By the way, I like the stock look so I used my OEM tail pipes.

JamesC

Tru2Chevy

3" catback would give you a nice gain in power and sound over a 2.5" catback.

- Justin

Air_Adam

2.5" single is not enough for a stock 305, let alone any 350 thats been played with. Get a 3" exhaust on there and be happy

hot92RS

Guys, Chris5K did not say that he had 2055s, the setup that I have works well(2460's non air-no smog in FL) I had my shop customize the ypipe to 3" and then went 3" all the way back. I am not saying that less backpressure is better, I am saying that if he has the opportunity to make a 3" system, he has some room to grow, but certainly, he doesn't want to go any smaller than 3" if he has the opportunity.

Chris5k

Ok, so i looked up the part #'s for you guys.. the headers are the 2460's
and heres the y specs...
HOK-16767HKR
Y-Pipe Inlet Attachment: 3-bolt flange
Inlet Diameter (in): 3.000 in.
Y-Pipe Outlet Attachment: Slip-fit
Outlet Diameter (in): 2.500 in.
Y-Pipe Material: Steel
Y-Pipe Finish: Aluminized
Oxygen Sensor Bung Included: No
Catalytic Converter Included: No
Gaskets Included: No
Hardware Included: No
Quantity: Sold individually.
Notes: Designed to fit Hooker 2460 Competition headers. Will fit all small block Chevrolet Gen I engine combinations.


So as previously questioned.. would the 3" make a difference? its already bottled down to 2.5" at the y, would it be worthwhile? I cant believe hooker made that damn y 2.5" when the majority of the catbacks are 3"......

Air_Adam

If you are talking about the two pipes (off the headers) that merge together being 2.5", then thats pretty adequate for performance. If you are talking about the pipe AFTER the Y being 2.5", then thats really not enough for any kind of performance engine, and you are being held back. 3" would be the way to go there.

JamesC

iTrader: (5)

The Y-pipe is three inches at the collector (and by many accounts on this board, the Hooker Y is the best made for cars). My Catco is three inches in and out. My Hooker catback is three inches. Can't do much better than that.

My bad: I thought you were speaking about the 2055's.

JamesC

Chris5k

This new engine just feels weird, i was expecting more out of the combo.. and it felt much more torquey with the y-pipe being the only exhaust on it too so ill be putting some more parts on the credit card for the hooker catback...hopefully with good results.. i was thinking a before and after dyno.. well see.

James.. that hooker part# that you posted for the cat back is listed for the 86-92 tpi HO models... is that a dual cat system?

Chris5k

Adam... yes the rest of my exhaust is the same size as the hooker y-pipe's original outlet.. 2.5" thats why im really hoping my engine could see noticable gains from the upgrade.. and thats why im here to question you guys before i blow almost 300 clams thanks guys

Air_Adam

That 2.5" single is whats choking your engine. You'd see a HUGE gain if you changed it to a real 3" system with 2.5" pipes off the headers. What I mean, is two 2.5" pipes (one on each header) down to a Y-pipe that has a 3" outlet, and hook that up to a catback that uses 3" pipe back to the muffler. That will really get your motor to take its ***** out of its purse

Most of the Y-pipes that have small outlet pipes can be cut in the middle of the Y-collector (where the two header pipes enter) to get a 3" outlet and just have an exhaust shop fab a section of 3" pipe to fit between your catback and the new outlet of your Y-pipe. This is what I had to do with my Hedman headers and Y-pipe. It had 2.25" header pipes and a 2.5" outlet pipe. I cut off the oulet pipe right in the middle of the Y-collector, and it gave me a 3" outlet. I hung my Hooker 3" catback under the car, drove it to an exhaust shop, and had them make me a section out of 3" pipe to replace the 2.5" pipe that I cut off the Y-pipe. Worked great!

Chris5k

actually, i have a collector from flowmaster thats dual 2.5" into 3" .... maybe that will work, ill see if its too big or not... but yeah im definately gonna give this a shot.. id like to dyno it before i get the exhaust just for ***** and giggles

JamesC

iTrader: (5)

No.

JamesC