i have an automatic with the 305 tpi engine. it rated at 205 horse power but with a manuel its rate at 230. why is there such a differance? shouldn't both transmissions have the same rating?

 

They should, but GM didn't see things our way! The 230 HP sounds more like the 350 TPI (auto) ratings however, not the 305.

------------------
Working on:
'84 Z28 LG4 305 with 200,000 original miles!
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350 (ZZ430)
using primarily GMPP parts.
Short block sitting on a stand. (Man, those Fast-Burn heads sitting on it look good!)

Starting to look like the Kicker poster child!

ASE Certified Master Tech

 

The later 305 TPI 5psds were indeed rated at 230hp. They recieved a better cam and the better dual cat exhaust.

------------------
Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

 

same cam, different exhaust (small exhaust manifolds, y-pipe, and catback)
This topic has been done to death, and then some... I will say no more.

------------------
91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

Built on Wednesday

 

Officially the 5spds got a better cam then the auto 305 TPIs, they did from 87-89 for sure. There is some debate as MrJ has pointed out to whether or not the 90-92s did. There is still no proof to say they all got the good cam in 90-92...

It should be noted you could also officially get a 5spd 305 TPI w/ 205hp in 91-92. It had single cats and again "officially" a small auto cam. There is some proof now that this 5spd engine did have the same good cam as in the 230hp 305. That however does not mean that all 305 TPI autos necessarily got that cam.

------------------
Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray


[This message has been edited by Ray87Z (edited April 18, 2001).]

 

I said I wouldn't say any more, but I can't help myself, lol.

Officially, all 90-92 305 TPIs DID get the same cam. The myth was that they didn't. A while back, someone, Drew I believe, posted a scanned pick of a GM parts invoice listing camshafts for all thirdgen F-bodies. The 90-92 LB9 (all of them) and L98 has the same part number. The 87-89 LB9 auto shared the same part number as the 88-92 L03.

 

If you'll remember that post it was pointed out that the list posted left out other cams from other years as well. I believe it was Vader that pointed out several it was missing. Not hard to believe they left out the peanut cam for 91-92... It is certainly possible that they all got the better cam though, it would be a nice change from the way GM screwed the rest of the years.

I still say the only way to be sure is for someone here to pull the cam out of their 91-92 305 TPI auto and measure it...

------------------
Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

[This message has been edited by Ray87Z (edited April 18, 2001).]

 

what seems to be unmentioned here is the G92 option. the auto and standard 5 speed were the lower hp small cam and the 5 speed G92 optioned cars included the larger cam.

 

did you miss the huge debates we've been having here over this?