I hope to buy an LB9 5 speed GTA this month...Without a power adder, what can you get out of the 305?


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89 GTA Trans Am L98
Wins: 2 Early 90s Stang GT, 4 wheeler, Chevy Malibu
Losses: New Camaro...bastard

 

That depends on what you're willing to spend on it and stuff like that...

Without digging into the motor, i.e. with a good set of headers and an exhaust, and the usual "free" or at least very cheap mods, you should be able to get mid 14s out of it, 14.4 or so

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"So many Mustangs, so little time..."
ICON Motorsports

 

Since it is a special car (366 made that year with 5 speed), I would prefer to keep stock appearance. So what if I put in a cam, did some headwork on original heads, and did some porting of original tpi system...what would that get me?

And then what if I added a power adder (turbo preferred, but supercharging would be fine)?

 

I would think it would worthless to do headwork and changing the cam without headers. I don't think putting headers on would deface the rarity of the car.

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"Rice burners are like tampons...Every pu$$y has to have one"
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
3" Hooker CatBack w/Aero Chamber muffler
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat, just switched to 180* b/c of winter coming and going to college in the mts.
3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite

 

But couldn't I put some cut-outs, or pull out plugs on the exhaust and solve that problem when I race?

 

ditch the stock exhaust manifolds. I bet that's an 1989 GTA, since I also own 1 of those "special" 366 with a 5spd. BIG DEAL, that emblem on the fender doesn't say TTA, it says GTA, they made like 9000 GTAs that year and plenty more during the other years 87-92. Sorry to rip on you, but that's ridiculus to keep the stock manifolds and expect(want) performance. It's also ridiculus to consider your car a collector's car in my opinion. Also the comment about supercharger/turbo, totally negates that keeping it "stock" appearence. "cutouts"? sure they look/sound stock too. Come on man.

I suggest you do alot of time researching/browsing the older posts before you go out and buy anything.

With some money(alot of mid priced mods $100-300each) good cam and stock heads(ported), I'd say high 13s are expected with traction. Big bucks AFRs with the stock 305 bottom end if it's still alive, I bet mid to low 13s are possible in 305 N/A with traction.

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14.62@96mph headers, muffler, chip, ghetto stuff, duct tape
89 GTA 305 TPI 5 speed 3.42 gears

 

I don't think he is wrong to consider his car special it's a LB9 5-speed they are rare. So what if you have one too.

 

With a supercharger you should be able to get into the 12's.

Twin turbo definately in the 12's. Read some of the signatures in the Power Adder section.



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http://www.gruveb.com/z28

 

A supercharger may negate the stock appearance, but it can be returned to stock appearance...

I've always wanted a 5 speed GTA...not common, and special to me...did not call it a collectors car...I kind of collect cars...but except for the 5 speed they are mostly junk. I would like to keep this one nice since it is mint. If I start changing things and doing this and that, it will be a piece of **** like the others.

I just wanted to know what I can expect from the car performance wise without sacrificing the integrity of the car. Basically what is the weakest link? Trans. Rear?

I also don't want the car to be loud in normal driving, unlike my L98 Auto with slp headers and 3" pipe with no Catalytic converter.

thanks for the responses

 

hey jackass, i have a 88 gta thats not a 5 speed and i promise it will put your's to shame, how dare u knock on a third gen

 

I may have been a little harsh, but it will be just as easy if not easier to put your stock manifolds back on than to make it look stock again after a supercharger. The T5 is weak and the 9-bolt is probably weaker. (At least mine was. It's gone now though regardless.) And you can't make either of them to be reliable behind a supercharger. I say don't worry about that stuff if you want your car to look "mint" keep the exterior and interior original. I doubt anyone would say, "damn you ruined that fine automobile by putting a supercharger or headers on it." or a T56 which is basically undetechable from inside the car or outside on the pavement. What kind of budget are you looking at?

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14.62@96mph headers, muffler, chip, ghetto stuff, duct tape
89 GTA 305 TPI 5 speed 3.42 gears

 

For a fact most off the shelf headers are only worth about 15 hp over stock exhaust manifolds [duals or large single] using a freeflow system on a moderately modified V8[most street engines]. With a performer or weiand 8004,cam and ported stock heads you can make 300hp [gross hp]. In my opinion headers are hardly worth the money and problems on a street car

 

Supercharger will only make it look other than stock from under the hood. Otherwise, you won't see it at all.


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http://www.gruveb.com/z28

 

"Headers are hardly worth the money and problems on a street car"

Man, what are you talking about? $330 = .3 or more(traction) sec drop and 3+mph gain in the 1/4 on a practicly stock car(probably more than 15hp I'd say). What problems are you talking about? Nice sounding exhaust, nicer looking engine bay, better performance? I've had mine(edelbrocks) for ~3+months now with absolutely no problems, I haven't touched them since installation, never re-tightened bolts or anything. What are these problems you speak of?

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14.62@96mph headers, muffler, chip, ghetto stuff, duct tape
89 GTA 305 TPI 5 speed 3.42 gears

 

My budget...don't know...I'm willing to spend about $6000 on it in bits and pieces if I decide to go all out. If I decide to modify (and still keep an original type appearance) I would hope the rear end could hold up. I'd be willing to swap in a Tremec 5 speed since its a direct bolt on. I guess that would leave about 4500. Maybe spend 1000 on some custom interior modifications...leaves 3500+/- to spend on motor, brakes, suspension. I'm willing to learn and do some of the difficult things myself...

So maybe I am thinking of going ahead with the headers (400), manifold and runner porting (dremel), throttle body porting (dremel), head work (?), cam (250 - suggestions?), ET streets (275?), probably some type of concealed nitrous (500?)

High 12s possible Normally Aspirated?

 

Rearend stud girdle I've heard is the savor for the 10-bolt. I haven't seen one for the 9-bolts though. No slicks...death for a stock rear. 12s N/A with the stock heads ported or not, is not going to happen. High 13s yes, but high 12s nope.

Figure closer to $2000 for the tremec, you'll need a clutch(best time to upgrade) and expensive speedo adapters and cross member adapters, tremec backup light switch, (probably) different yoke for driveshaft to output shaft on the tranny(U-joint).

Do a search for fast 305s or 13 sec 305s, 305 times, etc. There only seems to be about 5 or 6 305s running in the 13s N/A on here. Find Tim Burgess I "think" he has an extremely fast 305 N/A.

For a cam crane 2032 is 214/220 .452/.465 int/exh. I've heard good things about it in a 305, also I picked one up used for $60, so I'll tell you my opinion as soon as I get it in. SLP I've heard good things about(~$330) and comp cams make one similar to the crane cam I mentioned.

BTW the T56 is pretty close to a direct bolt on with Spoon torque arm/driveshaft loop/crossmember kit(~350 ?) I haven't done it personally, but there are plenty of articles about that swap.

You seem to be interested in almost the exact same build/mods I'm doing. I want a close to stock looking GTA, probably ZR-1 wheels since I have a 4th gen rear and stock interior. I want 13s N/A with stock heads , mentioned cam and bolt-ons. Then I have a NOS nitrous kit(should be done this weekend, just have to do the wiring) for hopefully some 12 sec happiness.

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14.62@96mph headers, muffler, chip, ghetto stuff, duct tape
89 GTA 305 TPI 5 speed 3.42 gears

 

I've seen independent test done with off the shelf headers and stock dual exhaust runnig through free flow mufflers on a moderately modified 350,only 15 HP gain. The problems I'm talking about you wounldn't have experience in only 3 months,like exhaust leaks and gaskets,leaks from welds that didn't hold,rust outs that come sooner than exspected,not to mention more noise and heat. Remember I said off the shelf headers,probably some of the quality[exspensive]are better,"off the shelf headers" aren't tuned headers. It's hardly worth it on a street car for a 15 horsepower gain.

 

OK... personally I have no probs with the 305 5spd combo. I have one... accually had 2 but thats another story.

Newayz, my 88 GTA with a 350 turned out a best time of 14.2 last time it ran. I didnt do much to it: Edelbrock TES hedders, chip, air foil & ported plenum, k&n, ported plennum... the basic $hit. Had the stock 3.27 rear.

Now, my 92 Vert with the 305/5spd ran a 14.9 with the following: Edelbrock TES hedders(from the gta), air foil, k&n cone filter, Hypertech stage II and a 2.73 rear and a ported plenum. Pretty much the same as the GTA EXCEPT THE REAR. If my Vert had the same rear, (3.27) It would have atleast kept up with the GTA, at best ripped it by about 2/10ths.

This gives me pretty good faith in the 305. It doesent have the torke the 350 did, but it can definatley hold its own IMO.

Keep in mind all this was on the stock intake system too. Just my $.02

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92' White Trans Am Convertible, 305 TPI, 5 spd. 2:73's, Edelbrock TES, Accell 8.8's, Hypertech Stage II, TPIS Air Foil, Ported Plenum, K&N TB Cone Filter, AFPR, & A Little Bit Of Attitude!
-Best ET: 14.944 @ 93.11

88 Gunmetal GTA Hardtop... Project In The Works!

"GUYS, WE NEED TO FIND A MUSTANG TO RACE... THERES ONE! HOLY SH*T SHES HOT! SHES NOT GONNA GO... NAH... HOLY SH*T SHES GOIN!"

 

EZ-rollin, Your test you quote from may be correct, but isn't really relavent(spell?) here, obviously not a 3rd gen they're talking about.(dual exhaust?) off the shelf headers(are you talking summit($79)?) they probably are crap. I don't consider edelbrock headers of great quality myself or costly considering the options with 3rd gens. Effective YES. I'd say headers/muffler rank up there with the best mod for 3rd gens vs. maybe a chip from the right company as far as $$$ vs. performance and technical know how for installation. Both those mods gained me 6+mph and -.8+ sec ET.

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14.62@96mph headers, muffler, chip, ghetto stuff, duct tape
89 GTA 305 TPI 5 speed 3.42 gears

 

O.K. I'll concede these weren't specific to a third gen. F body. A set of off the shelf headers hooked to the same pipes/mufflers as the stock exhaust[can't remember what car]. Consider that an engine doesn't know headers from stock exh;it only knows how much backpressure it sees. So,if the headers only had slightly less backpressure then the hp gains would be proportional. I don't doubt you got hp gains with the headers but how much more than stock manifolds with the same pipes and mufflers?

 

who is going to keep their stock pipes when they do headers?

 

No,I meant the same size pipes and same mufflers as used with the headers.Only way to tell diffence in headers and stock manifolds.

 

ROFL......

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club