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Trying to get 300 to 350 horsepower

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Old 07-31-2018, 10:04 PM
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Trying to get 300 to 350 horsepower



Hi I have a 1989 trans am 350 and I’m trying to get
parts that fit correctly im new to basically anything car related so I think this is the right forum
but anyways I’m trying to get 300 to 350 horsepower
i have 49000 miles
mans the car is solid from the bottom up
just needs paint and bolt ons
so my question is what do I need to get specifically
if it was your car what would you add to get it there
thanks you very much I need all the help I can get along the way
oh and I want it to be naturally aspirated no turbos or super chargers I appreciate the help I can’t get
and I have about 2000 to put into it
could wiggle up a bit
sorry if you see this post in differnent forums I had people tell me I was in the wrong threads
Old 07-31-2018, 11:02 PM
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Engine: 350 Vortec, FIRST TPI, 325 RWHP
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Re: Trying to get 300 to 350 horsepower

$2000 isn't going to do it.

Heads, cam, exhaust including headers, injectors, fuel pump, tuning..... not to mention all the stuff that's going to break, the mistakes that will be made due to ignorance or inexperience, gaskets, seals, maintenance items, etc.

You will be doing your own labor? Do you have the tools? What professional help is available to you?

GD
Old 08-01-2018, 05:53 AM
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Re: Trying to get 300 to 350 horsepower

Originally Posted by GeneralDisorder
$2000 isn't going to do it.

Heads, cam, exhaust including headers, injectors, fuel pump, tuning..... not to mention all the stuff that's going to break, the mistakes that will be made due to ignorance or inexperience, gaskets, seals, maintenance items, etc.

You will be doing your own labor? Do you have the tools? What professional help is available to you?

GD
so say money wasn’t the issue out of all things you listed what exactly would you get brand wise and styles

I will be doing it with my neighbor who is a car shop mechanic he sai I could use all the tools in his disposal

what head what cam, headers, intake ,gaskets seals and anything you mentioned should I get and if I can’t do the work myself I’ll take it somewhere to get done
Old 08-01-2018, 08:26 AM
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Re: Trying to get 300 to 350 horsepower

Are you planning on keeping your AIR system?

Can you weld?

Are you planning on staying TPI?

Dyno Don Headers are about the best shorties out there but hooker are also good. Besides Don most Y pipes will require some modification to make decent.

There are some stickies in the exhaust section.
Old 08-01-2018, 09:03 AM
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Re: Trying to get 300 to 350 horsepower

What headers work what version of hooker headers
and what intake should I get that will fit under the hood?
Old 08-01-2018, 09:06 AM
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Car: 86 Imponte Ruiner 450GT, 91 Formula
Engine: 350 Vortec, FIRST TPI, 325 RWHP
Transmission: 700R4 3000 stall.
Axle/Gears: 9 Bolt Torsen 3.70
Re: Trying to get 300 to 350 horsepower

You will be looking at $1000 just for good exhaust. Dyno Don headers and y-pipe. And then custom for the rest.

AFR makes some of the best off the shelf heads. Looking at around $1600 for a set.

Comp cam kit is typically about $800.

First fuel injection intake (stock TPI will just choke the engine) - $1000:
https://firstfuelinjection.com

Southbay injectors - probably at least $200 there. Another $100 for a high volume fuel pump.

Then there's tuning. You're going to want it on a Dyno. Expect this to be $500 to $1000

Then there's probably at least another $1000 in misc. gaskets, seals, fluids, and other accessories that you will need/want to complete this picture.

You need to triple your budget. At least. If you want to be successful and reliable and not do this 3 or 4 times.

GD
Old 08-04-2018, 10:03 AM
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Re: Trying to get 300 to 350 horsepower

Well said General.....
Hotrodding cars is a bottomless pit of cash. It’s an endless pursuit for more power more speed. You reach one goal...the next day you set a new one. Like you said...make a list of what you think you’ll spend...then triple it.
Old 08-04-2018, 11:25 AM
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Re: Trying to get 300 to 350 horsepower

It gets exponentially more expensive the more power you want. I just finished up a 600 HP AWD import build that came in around $23,000 for the engine and chassis/suspension. Most people really have no clue what reliable power costs. It really doesn't matter what you are building either. It's all expensive for the best quality parts. Some makes/models are just more expensive than others.

GD
Old 08-04-2018, 02:20 PM
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Re: Trying to get 300 to 350 horsepower

Originally Posted by GeneralDisorder
It's all expensive for the best quality parts.

GD
This guy doesn't need the best name brand, new parts. This guy needs "i just want to have fun" parts.

If you want to stay small block chevy try to stay with used parts (when allowed) or brand "B" parts (Summit, Jegs, Speedway brands). AFR heads are king of the hill (as a mass produced head goes) but a Summit brand aluminum head would work just fine for you.
The cheapest route would be to buy a crate engine from a large company like GM, Summit, Jegs or one of the large companies on eBay. IIRC the 383 engine that Summit sells is a good deal. You can buy a carb and have a guy tune it on a dyno. If you have zero experience then an aftermarket efi system on a sbc isn't a good idea. An LS engine would be utterly reliable while easily making 300 rear wheel horsepower and possibly not much more monetarily but with you having no experience I think it's too long and steep a hill for you to climb.

My advice for this new project you have is that if the engine is running well just don't touch it. Replace or upgrade the suspension, change the rear gears to 3.73 or 4.11, upgrade the exhaust and you might find that with some new paint it's enough fun. If you have a good running TPI or a carb these cars with those changes are still fun to drive in traffic and autocross.
Old 08-05-2018, 12:39 AM
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Re: Trying to get 300 to 350 horsepower

Thanks for the input
I have a nice suspension
koni adjustable shocks
3” magnaflow exhaust with butterfly valve
and welded in subframe connectors

i love how my car handles
its a blast to drive

just needs a little more eumph of the like for me

obviously it needs the tlc things like paint and newer ttop seals but the inside and the bottom of my car is flawless
just need a little more out of it
and I may not know what I’m doing now but eventually I will
and I need all the input I can get
Old 08-05-2018, 08:33 AM
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Re: Trying to get 300 to 350 horsepower

And its not how much money you spend on your car.Its how you spend it wisely..In the mean time you can maximize what you have ,By maybe have your stock heads ported,and matching the intake to them.If you don`t have a true dual exhaust ,I don`t know what your state emissions laws are.With twin high flow "cats" And give it a good tune .And see what you have.
Old 08-10-2018, 07:31 PM
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Re: Trying to get 300 to 350 horsepower

The problem with TPI is to get any RPMs and high HP numbers you have to replace nearly everything. Ask yourself if you want great track numbers or is it more important to have fun driving it everyday. If it's the latter then it can be done while using some of your current stuff. You already have a good exhaust, find some good (don't need the best at this power level) headers, better gears (def don't go above 3.42 on TPI), higher stall converter. Those 3 things will make a big difference in seat of the pants acceleration and more fun to drive. Dig into the engine later after you've read more and can do a lot of the changes at the same time rather than ripping into the engine repeatedly. Just my $.02.
Old 08-16-2018, 07:53 AM
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Re: Trying to get 300 to 350 horsepower

My 2 cents, the OP is asking for about 55 over the the rated HP. I don't think he has to swap motors or make radical cam changes.

What I would do is first establish the base line - get it on a dyno to see what it's putting out at the rear wheels. Then add some bolt ons like headers/exhaust, drive pulley, Changing the Torque conv to a 2500-2800 stall and gears to 3.42's helps tremendously. Every little change adds up - porting intake and heads would help for better flow. maybe 1.6 rockers if clearance is not an issue.

Take a look at VincentZ28 - just changing exhaust and headers and gears he ran 13.20'S in the 1/4

https://www.thirdgen.org/forums/tpi/...ed-before.html
Old 08-16-2018, 08:27 AM
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Re: Trying to get 300 to 350 horsepower

Originally Posted by x55Cam
My 2 cents, the OP is asking for about 55 over the the rated HP.
89 Trans Am 350 (per the OP) would be 230-240hp depending on options, -5hp if you believe the claims that Pontiacs lose 5hp vs the Camaro... So potentially we're talking 225hp jumping to 300 to 350hp, that's 125hp on the long side. Not an insignificant increase.

Bolting on an underdrive pulley, torque converter, and gears isn't going to increase HP a bit. It'll reduce parasitic drag and change the manners of the car, but it's still going to be 225-240hp. Porting, and a set of rockers, should pick up a little, but not nearly 100hp.

Originally Posted by x55Cam
Take a look at VincentZ28 - just changing exhaust and headers and gears he ran 13.20'S in the 1/4
A dubious claim, at best. If true, it's not indicative of a typical gain for those mods.

Old 08-16-2018, 10:09 AM
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Re: Trying to get 300 to 350 horsepower

Originally Posted by Drew
89 Trans Am 350 (per the OP) would be 230-240hp depending on options, -5hp if you believe the claims that Pontiacs lose 5hp vs the Camaro... So potentially we're talking 225hp jumping to 300 to 350hp, that's 125hp on the long side. Not an insignificant increase.

Bolting on an underdrive pulley, torque converter, and gears isn't going to increase HP a bit. It'll reduce parasitic drag and change the manners of the car, but it's still going to be 225-240hp. Porting, and a set of rockers, should pick up a little, but not nearly 100hp.



A dubious claim, at best. If true, it's not indicative of a typical gain for those mods.
I don't feel I'm in a position to question some one that claims they ran 13.20's with bolt on equip. Much of the performance increase in gearing , exhaust and intake that can make quite some difference .- Maybe he also ran with track tires?

The op wanted to increase to 300 HP , assuming that the 245 is the base. If you want to go real world and say 225 then 275 HP would be realistically attainable , (50hp) not 300-325 - I'm only going by what the base is. I never claimed that with these mods 100-125HP could be attained.

The ops needs to base line and go from there. Over coming parasitic loss can make a difference in how it responds and performs under acceleration. But also by adding headers a less restrictive cat/muffler, etc. it's the most user friendly accessible mod.
Old 08-16-2018, 10:57 AM
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Re: Trying to get 300 to 350 horsepower

A better way to look at this is what would you like you car to run in the 1/4 vs, I need this much hp.... Think about it. everyone races dynos today
Old 08-16-2018, 12:10 PM
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Re: Trying to get 300 to 350 horsepower

Alternatively - a basic turbo kit, fuel pump, injectors, and tuning will easily do the 100 HP he craves.

GD
Old 08-16-2018, 03:52 PM
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Re: Trying to get 300 to 350 horsepower

Originally Posted by x55Cam
The op wanted to increase to 300 HP , assuming that the 245 is the base.
Actually, this is the second or third thread from the OP. The previous thread he was after 350-400hp.

And the rated HP for a 1989 Trans Am 350 is 225-235hp, not 245. The Camaro L98 didn't hit 245hp until 90, and the Firebird was consistently published as 5hp less than the Camaro. If OP has a single cat (non-G92) 89 350, he might hit 245hp after full exhaust and some tinkering, before factoring in driveline losses.

This is getting silly. There are a handful of recent threads covering this topic already. TPI cars only respond so much to little things, and big things generally fly in the face of TPI's design, leading to difficult times attempting to reach a predetermined goal. Even the car magazines, and TV shows, with sponsors in their back pockets and astronomical budgets haven't really gotten 350hp out of a TPI car with bolt ons.

You can't tell someone that exhaust and a gear change is going to make their car run 13.20s. Because then they go out and spend their hard earned money trying to do it, and when it doesn't live up to the expectation, what's going to happen?

Old 08-16-2018, 06:00 PM
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Re: Trying to get 300 to 350 horsepower

I will eventually have my '89 L98 dynoed - the only mods made to it was porting/polishing the heads and intake and .030 over forged pistons which I think are
9:5:1 - The torque conv is a 2800 stall and the rear are 3:42's . The exhaust will be modified but no headers. Should be interesting what it reads.
Old 08-16-2018, 08:02 PM
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Re: Trying to get 300 to 350 horsepower

Originally Posted by Drew
You can't tell someone that exhaust and a gear change is going to make their car run 13.20s. Because then they go out and spend their hard earned money trying to do it, and when it doesn't live up to the expectation, what's going to happen?
Heh. Nothing at all. Because this is the Internet. Car forums are like the Special Olympics. Even if you win.....

GD
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