What is the major difference between the two engines offered? They are both 5 litre v8's 305's right? So then what is the difference?

 

one of them is the 4bbl (LG4) engine and the other is the TPI

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1985 305 Z28
White w/Red interior
Mods:
GTS Headlight Covers
K&N Chrome Element and Filter
Flowmaster 80 series muffler
Chrome Valve Covers

 

I'm guessing this has to do with the major hp difference right?

 

yeah

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Hey feel free to chat with me on AOL IM if you wanna.. Darkhal2000!
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in 85 there where acctually 3 motors available. There was the LG4 carb motor(155hp/250tq), The l69 motor(190hp/260tq) and the TPI H.O. motor(215hp/285tq). All of these motors where 305s. I have heard rumors that the TPI motor in 5 wasnt available in a 5 spd but the others where.

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1989 pontiac firebird
bright red exterior(just repainted)
grey interior
5 spd
305 TBI (stock)
WS.6 formula wheels
3.73 posi rear end
http://members.aol.com/j007golden/Mikey89.html
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1985 trans am
factory bright yellow
4 wheel disks
16 inch wheels
305 TPI
power antenna and mirrors
t tops

 

These are the correct HP and Torque specs of those engines: https://www.thirdgen.org/newdesign/tech/techdb.shtml

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Looking For:

87 IROC-Z 350 TPI
84 TRANS AM 305 H.O.

[This message has been edited by IROCZTWENTYGR8 (edited February 25, 2001).]

 

Thanks for the info guys.

 

I beg to differ. There is a difference between a 85 stock z28 and a stock ta
The z28 lb9 is 215 hp. The ta is 210hp 270lbs-ft torque. The reason for the difference is that the z28 has a different breather and hood. (Per the pontiac listed specs in the pontiac catalog and pontiac shop manual I have)
Also there are no 5-speed lb9's for 1985.
The engine produced to much torque for the transmission. As soon as I finish my web page I will scan the pontiac info.

If someone tells you they have a 5speed 1985 z28 or ta it can only be the lb4 or the 4bbl 5.0 L69

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85transam 305 TPI 210hp

 

L69 was an IROC only option in 85/86, the 2 Z28 engines were the LG4 and LB9.
Major differences, i'd assume that the LB9 used the same short block as the L69 so, it has different pistons for more compression, and x rods. The Lb9 also has a much healthier cam than the LG4.
Beyond that, the entire intake is different, the LG4 uses a computer controlled carb (CCCS) and the LB9 uses TPI. Also, the LB9 uses a larger y-pipe and larger intermediate pipe to the muffler. I think all the HO cars got a single elctric fan in 85 too.
...ed