SLOW30th-TA

iTrader: (29)

Well I usually dont start threads because I can find things through the search but I have not really found any sound information when it comes to headers. Now I have not purchased any headers yet but my plan is to run a y pipe with cut out through an SLP dual/dual. Is the gains from 1 7/8 noticeable over 1 3/4? I know that boost is measured by restriction so for people who have switched to a larger header, did your boost decrease?
I ask this bc I could save myself about $400-500 by going with LPP's over Kooks or ARH's. I would go with the TSP headers but I want stainless steel. Opinions from people with both headers and from people who have switched from one to other would be appreciated.

My set up will be:
347 - 9.5 -1 Forged
D1SC - 10-12 lbs
317 heads
Decent size blower cam (probably Speed Inc SC2)
6 speed

Gauge

iTrader: (3)

If price is an issue, go with the cheaper headers. I have 1-3/4" primaries, and I'm makeing 650RWHP on a D1SC at 14psi. If I want more power, headers are not where I'll invest my money. I could make more power for less money with a pulley change.

If price is no object, I'd go with the 1-7/8" headers, but if you already have 1-3/4" or you can get them much cheaper, go that route. Once you've gone FI, making more power is usually easier and more cost-effective with a change in boost than engine modifications.

WAHUSKER

iTrader: (4)

With "only" a 347 & a D1 you'll be fine with 1 3/4" headers. Me & my neighbor both made over 600 rw with that setup.

Boost numbers can be misleading. With big cubes / blowers it's more about moving air volume. I have 1 7/8 on my 408 F1 combo....

'Trust'

iTrader: (24)

I have coated 1 7/8's Kooks, exhaust restriction when it comes to FI (superchargers anyway) does have an affect on overall power output. However, if money is a concern, which is sounds like it is, just get a 1 3/4 header.

SLOW30th-TA

iTrader: (29)

Thanks guys. Budget is not a really a problem as the car has been down for quite a while and if the 1 7/8 headers benefit more than I dont mind saving a little longer. I just want to see some proof/ dynos #'s/ or an actual case where the 1/8'' makes a noticeable difference....but like most have said, people find it a lot easier to change a pulley vs. swapping $$$ and headers to see less restriction.

viper9403

iTrader: (14)

I would do it right the first time and get the 1 7/8's you'll be happier down the road. Unless you really need to save the extra green...

Jimmy P

iTrader: (177)

I had Pacesetters and I felt that they were chocking the motor up. I now have the Kooks 1 7/8" - 2" with 3.5" collectors on mine. I would of went with the 2" but they weren't available at the time. I have been told by big time racers that the exhaust realy matters on a supecharged car.

SLOW30th-TA

iTrader: (29)

I know there are more SC guys than this with results.

DanWS6

iTrader: (5)

I switched from 1 3/8 QTP to 1 7/8 TSP headers but I can't give you a valid comparison since I also forged my motor and switched to a smaller blower pulley.

Mr.Big

1st let me say I still have the 1 3/4's on my setup... making 786rwhp on boost alone...

with that said, "If" 1 7/8's would have been offered back in 2005 when I bought my car and couldn't wait... I surely would have gone with the larger tubes... So long advice longer, go with the 1 7/8's if you can afford it, and do it right the first time, however you CAN make decent power with the 1 3/4ers...