Obviously headers would a larger hp increase.
But the 350 TPI exhaust manifolds should alot cheaper and better the stock 305 TBI exhaust manifolds. What do you think? Any one know the size differences and if they would bolt right up?

BTW- engine is a 305 TBI and I can't afford to turn it into a rocket ship-(have to get a paint job too)
just want a cheap mod

------------------
Dare to be different-
build a 305! <gasp!>

 

Well if u know how to install them urself, I guess that would be fine for a cheap upgrade. But seems like it would be a big hassle just for a small upgrade to me.

------------------
Eric Natzke
91 Firebird 305 TBI
"It Ain't Stock"
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

 

Kevin L. and his dad did this to their RS. they got like a 7 or 8 Hp/TQ increase. You can also do this and try to get a new better Y pipe made for $100. The SLP Y pipes are $200. Or if you don't need to be 50 state legal you can get the non certified Hooker headers for around $150. They have air tubes but no 50-state legal certificate I believe.
The stock 305 TBI exaust manifold outlet is 1.75"(or 2") and the TPI exaust manifolds are 2.25"(or 2.5").

------------------
-Tas
'89 Formula WS-6
[soon to have Hooker 1-5/8" 50 state legal headers installed]

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Super GRK_Taz World
EFI & Intake Options
AOL IM: superGRtaz

[This message has been edited by Tas (edited March 19, 2001).]

 

Does anyone know the part number for the 350 TPI exhaust manifolds. I wonder how much they are new at the GM Parts Direct??

Mike

 

Tas, no we did not. We replaced the y-pipe, cat and cat-back with a stock IROC piece, but the exhaust manifolds are the same TBI ones. We had to modify the y-pipe too, as the 350/305 TPI and 305 TPI/TBI manifolds dont line up. The 350/305 TPI manifolds have a 2 1/8" outlet and the 305 TPI/TBI manifolds have a 2" outlet. I have pics if you wanna see.

For the hassle of changing them, its not worth it. Save up for headers, or leave the stock ones on there. You'd have to love punishment to do it.


------------------
West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

[This message has been edited by Kevin91Z (edited March 19, 2001).]

 

ah ok. I knew the TPI Y pipe wouldn't match to the TBI so I thought you changed the manifolds too.

 

i though about this option as well but instead i pick up a set of used headers , sanded them down myself and coated them POR-20. ya i had to do some work but its really worth it.

------------------
91 camaro RS
- 305 TBI
Mods: Performer tbi intake, 1" TBI spacer, K+N, jet fan switch ,160 thermo, accel control module, Jet Stage 2 chip, edelbrock TES headers, Compleate 3" Flowmaster exhaust, Edolbrock springs, KYB struts and shocks

Soon to come . Posi 323 rear end , aftermarket LCA,s and panhard bar , Ascd ram air hood, Z28 spoiler and grille , white guage faces.

 

If you have an IROC the outlets on the manifold are 2 1/2" to begin with.I know this from doing many small block S-10 swaps for IROC manifolds are the best ones to use.

 

Don't think so- I have on those TBI IROCs

------------------
Dare to be different-
build a 305! <gasp!>

[This message has been edited by 871LEIroc (edited March 23, 2001).]

 

The stock TPI manifolds from GM will run you more than most headers will anyway! So its just not worth it. Manifolds and headers are a pain anyway so if you wanna do something about it, just wait till you have the money!