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Tpi looked stock but had ridiculous amount of power. How is this possible
Hi all, I'm new and gonna ask a question. My step father use to own a 86 iroc that the hood says it had a 5.0 it was dark maroon in color. I was aboUT 10 years old at the time when I saw this car fly. I mean he even talks about it and we are both mechanics now but we never understood what was done to this 5.0 tpi beast. He would kill corvettes and and burn out in first threw 3rd gear easily. He was a mechanic back then and he put 4 transmissions 700r4 in it but said the motor just wouldn't blow. So he didn't tear it down to see what was inside. Popped the hood and he said it was a dirty looking tpi. Now we couldn't verify it was 5.0 but it was ugly under the hood. What in the world would somebody have Done to this iroc that gave this thing so much power?
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Everything on the car looked stock. I'm a mechanic and I know this car didn't beat z06 corvettes with just a rear end. I know your trying to figure it out but maybe a x police car? Chipped and tuned maybe? 350 bored out? Anybody who looked under the hood back then would've thought it was a terd. Why I'm asking is I just bought an 88 iroc with a 305 and need to know how that car was so fast to were it would burn rubber and get sideways at 70mph
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Not to mention. Everything from exhaust to motor and transmission was stock looking. Rear end to all components under hood. No lope when u started it so sure it didn't have a cam in it. Injectors looked dirty to match the motor so it didn't look like it was messed with at all!
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Exactly what I need to hear.. so it looking all stock. 5.0 tag under hood. And step dad says he looked at numbers on block. He claims it's an x police car. With a high performance chip. I see on here 5.0 tpi hard to get them over 400hp. So u think it might have been bored and 202 heads? And rear end gear changed?
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
My step dad recalls everything but like I said before he is the one who verified the 305 block and tpi looked untouched and filthy like it's been on a rocky road collecting dust for years. He til this day talks about it and we just wanted to know if anybody could come to conclusions on what maybe was done to the 305 tpi for that much power to be produced and beat z06 vette
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Not once have I got a legit answer from this. Yes I was 12 years old and yes me and my step dad til this day talk about the iroc from hell. He obviously wasn't a child back then and he knows the car had a tuned port 305 block. What he doesn't know is why it had so much power where it wouldnt hold up a 700r transmission in it for more then 6 months. It looked stock he says. I just bought my 88 one week ago and he states that everything was the same thing. So my question wasn't am I dreaming because I was a kid. I'm asking what your opinion is on what could possibly be done to a 305 tpi to have so much hp with everything stock looking on the outside
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Well, if what is said is true, I had a 1985 Z28 305 tuned port w/700r4 tranny back in 1986. It was a fast car back in 1986 compared to anything made back then. But if your step dad bought the car used in whatever year, who's to say it wasn't a 350 bored 30 over to a 355 with ported plenum and intake, bigger cam, ported corvette heads, chipped, bigger injectors? You can have a bigger cam without a "lope" to it. I laid two black marks across a city block parking lot with fresh paint on the parking spots. Lol Now, granted the parking lot was smooth with fresh yellow paint on the lines. Now if it was a 305, they are high winders but because of the restrictive stock intake, it would fall flat on high RPM's. So, 1, either you both are remembering bigger than was true, or 2, that motor had a ton of internal work done. My 1985 Z28 had 215hp, and the 1986 IROC had 190hp from 305 factory TPI motors.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Ok so since I have no clue of what was done to his. I almost guarantee it wasn't an illusion from my past. He works on semi's and been a mechanic most of his life. Now obviously nobody will ever know because it's probably in. Junk yard somewhere because it wasn't the greatest to look at. I just remember he was pissed off and I was in the yard and seen him burn the tires off 1/8 mile if not more than that down the street. Yes I was 12 years old but I asked him to this day I wonder what it had?? Question is unknown but this is not made up. X cop car or highly modified but u would think if somebody put internals in. They wouldn't leave the outside looking like a rats nest
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Originally Posted by Iroc8t8
Ok so since I have no clue of what was done to his. I almost guarantee it wasn't an illusion from my past. He works on semi's and been a mechanic most of his life. Now obviously nobody will ever know because it's probably in. Junk yard somewhere because it wasn't the greatest to look at. I just remember he was pissed off and I was in the yard and seen him burn the tires off 1/8 mile if not more than that down the street. Yes I was 12 years old but I asked him to this day I wonder what it had?? Question is unknown but this is not made up. X cop car or highly modified but u would think if somebody put internals in. They wouldn't leave the outside looking like a rats nest
X cop cars didn't have any more power than the production cars. Wisconsin State Patrol had a few IROC's for cruisers back in the day.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
I hate seeing people say. These cars don't have power this and that. I'm almost certain it had to of been a 350 chipped out and bored. Stock outside and if I dont recall he paid 1k for the car and he is 59 years old now.having on the porch storise about it to this day and I want the power out of my iroc I just got. He believes it was just chipped out. But who knows. So if u get say a 350 and trash my 305 tpi. How would I get my car to that power I explained.. I just asked him and he says it was posi Trac so another mentioned rear end change. So I just need more info on what could possibly have been done because I have the money. Just need help to get this kind of power.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Being a decent driver and having a decent rear will make a car pretty quick. As stated there's no way it was breaking traction at 70 without being a highly built motor.
You are asking how a stock motor made that much power.
The answer is it did not.
No one is saying the cat wasn't as you describe performance wise or calling you a liar, just that it did not do those things stock.
It had to have been built before you guys got it. Might have had a negligent owner that never cleaned it, or built with used parts.
Gears due make a noticeable difference though. My wifes car has a 305 tbi, it only has an edelbrock intake manifold, an unknown make and spec mild cam, and full 3 inch exhaust, as far as the motor goes, it does have 3.42 rear gears, and I have played with the trans governor to compensate and shift good in the power band I want at wide open. I can regularly get a jump off the line on my buddies 06 Mustang GT in it. Now granted not long past off the line he's passing me, the mustang has roughly 300hp, no way I'm pushing any where near that with my relatively stock motor but I still easily get him off the line and it frustrates the hell out of him.
Nothing short of a built engine swap is gonna get you 70mph traction breaking performance (when it's dry)
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Okay not saying it was stock. It looked stock just like a 86 tpi would. Also I understand it doesn't catch alot of people and he wouldn't make anything up. As far as power. Everything is unknown since the iroc is gone. Guess I'm going to start with a 350 bore to 383 and get some decent heads and a lt1 mild cam plus a chip. See where I am with the same power and let him drive it. I know it may sound stupid for me to mention a stock tpi burning rubber at 70mph with stock exhaust and stock looking tpi motor. But I rode in it and seen him take off multiple times. So hopefully I can get to that power and port and polish my own intake also. Thanks for all the replies.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Maybe someone swapped in a 350 TPI that was stroked to 383. With the right build, that could do it although I'm not sure how easy setting up a TPI on a stroker would be.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Originally Posted by Iroc8t8
I know it may sound stupid for me to mention a stock tpi burning rubber at 70mph with stock exhaust and stock looking tpi motor..
LOOKING is the key word here. To be able to do all the things you say it did it most definitely was NOT stock, regardless of how it looked. To do the things you state it did, at the least the motor was built and possibly a good set of gears.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Sorry, but your step dad confirming your "600hp 305" theory doesn't mean squat. My shop foreman who's been in the business for over 40 yrs swears his stock 5.3 truck is fast. My old auto shop teacher who had also been in the business over 30yrs thought his 383 El Camino made 450hp, when it had crappy heads, factory rocker arms, and idled like my stock LB9.
Not trying to say your an idiot or a lier, but a lot of these old dudes aren't the best gauge of performance.
Your first time in a car with a semi-loud exhaust and a cool body also tend to exacerbate any notion of speed, especially as a child.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
I've seen "600hp" 454 Chevelle's lose out to a cammed LS1 before. Said cammed LS1 only in the 115mph trap speed range.
Amazing how many HP that 600hp chevelle lost getting it to the ground.
Your step Dad's IROC was likely just a healthy 305TPI car on crappy all season stock width tires. 90% of people buy the cheapest tires out there.
TPI cars feel espeically strong due to their responsiveness in the mid-range. They make a ton of torque so feel very strong, but ultimately fall on their face long before making any real power.
There are a few people on these boards who have taking "stock looking TPI" and are making phenomenal power levels and they deserve every compliment they get for those builds.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Probably a bored out 350 with a decent cam that didn't have a strong lobe, supporting mods, ported intake and heads. Chances are that whoever did the swap didn't put any time into cleaning the engine or engine bay, they just did the work and didn't worry about the appearance. GM small blocks look the same. Try tracking down that car and see who he sold it to.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
I've already tried to track the car. I'm in indianapolis indiana so as far as I've gotten. Maybe they swapped lb9 to a l98 350 and some backyard mechanic pieced it together and made one hell of a car. With stock exhaust I just can't explain to myself neither can he. Now he had it for 1 year 8 months and put 4 transmissions in it because he claimed it had that much torque. Saying this online to the iroc family is a bit beyond believable but just because I was a kid and he is older guy doesn't mean nothing. We knew what we had. He loved the car but at that time he had to sell it for bills. He is 59 and remembers everything about the car. Just bought it like that in 1998 and looked stock. As far as we have gotten with what it had is l98 with cast iron heads (don't know what kind of heads) stock intake (don't know if it was ported) possibly chipped out. Car was a red color with fenders not matching each other and probably the most ugliest iroc u would ever see but as far as the power. Only both of us know and the guy I'm sure who built it. All I wanted to know is how could I get that power out of stock looking parts. I've tried my best to explain the power but every one seems to think it's a fluke. I just bought a 88 iroc since it's been almost 15 years later. He verified on mine engine his looked exactly the same. He is a chevy 350 guy also. Has built c10s. To 65 pickups frame up restoration. We both have built motors. He did it for a living. I also did but mostly motor swaps and so forth.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
All I wanted was to ex plain what I've seen out of an iroc and want that power. Because I want it stock looking to show to other guys who race it they will think I have a stock tpi. But what's on the inside is what counts right? So I'm assuming to just take a 350 4 bolt and tell my machine shop to bore it to 383 with eagle rods and ill get 202 heads with a lt1 cam and 90-92 tpi corvette injectors since I hear those push 24lbs. And port and polish my stock intake with Flowmaster exhaust with headers. See where I'm at with it then. Might change the rear end gear while I have it in the garage
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Headers and cam on L69 > LB9 all day, every day.
You were 12. It seemed fast and the power curve seems that way. It wasn't a 400hp car with a stock intake manifold; you've acknowledged this, and this thread has no end.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Originally Posted by Iroc8t8
All I wanted was to ex plain what I've seen out of an iroc and want that power. Because I want it stock looking to show to other guys who race it they will think I have a stock tpi. But what's on the inside is what counts right? So I'm assuming to just take a 350 4 bolt and tell my machine shop to bore it to 383 with eagle rods and ill get 202 heads with a lt1 cam and 90-92 tpi corvette injectors since I hear those push 24lbs. And port and polish my stock intake with Flowmaster exhaust with headers. See where I'm at with it then. Might change the rear end gear while I have it in the garage
you dont just bore a 350 to a 383 .. you need a new crank also .. the combo your trying to put together here wont be all that fast ..
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Great info redrock. I think I may just have someone build an engine from ground up and have it chipped and tuned. The car I have is a 1988 iroc. Says on tag 5.0. Can someone explain how I would know if it's a 350? And when I pull heads. How could I know if it's been bored or possibly different heads then stock?
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Look for block numbers on the back of the motor behind the driver side valve cover. This will tell you whether the block started life as a 5.0 or a 5.7.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
So I have a question about my 88 tpi 5.7 as far as I know about it it's been swapped out from a 5.0 to a 5.7. I do NOT know if they swapped out the intake or anything like that but do know that lb9 has 19lbs injectors and l98 have 22 lbs injectors. When I got car it had starting issues. Cold start it will not even start unless u keep pumping pedal for several minutes with a good charge battery or u use starting fluid and it will start right up. So car is running u give it gas it will hammer down for a few minutes then it bogs down and doesn't want to idle worth a crap or run unless u feather the pedal. Changed distributor. Changed plugs and wires. So now here is the fuc*** up part. Looked underneath it and found that the idiot before me obviously put the fuel filter on backwards and thought I hit a home run. Nope. Not at all. I could even shake it and something was broke in there. Anyways got a new fuel filter. Same issue. Hooked a gas Guage to the fuel rail while it is running. About 16lbs without the vacuum on. So before I bought the car heard from the previous owner he installed a new pump. Can't verify that but that's what I'm going by. Also when I turn key on I hear the pump and it sounds strong, any suggestions? ??
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Originally Posted by -=Z28=-
So hopefully I can get to that power and port and polish my own intake also.
hehehe
Knew it was going to go this route#! Not made up and believe what u want. I seen it. He owned it. We both know it looked stock but was one hell of a beast. One of those cars were u look back and think how was it possible to roast tires at 70mph with a stock looking engine. 5.0 at that and it was an 85 and had v belts and no rear end gears. He bought from a car lot so I'm assuming it was a trade in. Car is long gone and just wanted to let everybody know there was and it is possible to get A Tpi to produce that much power. Hp is Unknown. Car is unknown. 85 iroc was red and had multiple color fenders and door . Automatic and he went threw 3 transmissions in less then 1 year (700r) . Believe what u want but maybe one day whoever got this car might be the one to post back and say yes I had this car and everything is true. Mind blowing isn't it.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
I know at the beginning my numbers were off. We talked today about it and he did say it was a 5.0 for sure. Tpi stock looking. Cast iron heads. 1985 was the year. Unlimited slip he says because he mentioned both tires wouldnt catch all the time but most of the time yes. also not to mention there is a site online. Gm actually experimented on a l98 tpi with stock parts and produced 561 ft lbs of torque and about 516 hp to the flywheel.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Originally Posted by Iroc8t8
I know at the beginning my numbers were off. We talked today about it and he did say it was a 5.0 for sure. Tpi stock looking. Cast iron heads. 1985 was the year. Unlimited slip he says because he mentioned both tires wouldnt catch all the time but most of the time yes. also not to mention there is a site online. Gm actually experimented on a l98 tpi with stock parts and produced 561 ft lbs of torque and about 516 hp to the flywheel.
I was hoping this was some rare GM car such as the Heritage RS w/300HP and 6 speed
but I'm afraid it's more of a Talltale.
Cast iron heads, factory manifolds, no cam (etc) will have a hard time making 300RWHP. Even being generous, a 300 rwhp fbody with a 700r4 is not going to break the tire loose at 70 mph or even come close to a C5 Z06
Looks like you're trying to match the performance of this Iroc from Hell. Do your research and listen to the knowledgeable guys on here w/proven set-ups
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Originally Posted by Z28FAST1
I was hoping this was some rare GM car such as the Heritage RS w/300HP and 6 speed
but I'm afraid it's more of a Talltale.
Cast iron heads, factory manifolds, no cam (etc) will have a hard time making 300RWHP. Even being generous, a 300 rwhp fbody with a 700r4 is not going to break the tire loose at 70 mph or even come close to a C5 Z06
Looks like you're trying to match the performance of this Iroc from Hell. Do your research and listen to the knowledgeable guys on here w/proven set-ups
Your right. No way in hell. Making all of this up. Figured I could get possibilities with answers but it's fine. Wtf am I doing here like an idiot telling the world an 85 iroc was out breaking loose at 70mph and looked stock. Maybe I would say no f-ING way either
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Originally Posted by Iroc8t8
I know at the beginning my numbers were off. We talked today about it and he did say it was a 5.0 for sure. Tpi stock looking. Cast iron heads. 1985 was the year. Unlimited slip he says because he mentioned both tires wouldnt catch all the time but most of the time yes. also not to mention there is a site online. Gm actually experimented on a l98 tpi with stock parts and produced 561 ft lbs of torque and about 516 hp to the flywheel.
Unless there was a Turbo / supercharger and/or a metric crap ton of nitrous that is not true. The stock heads, intake and exhaust simply do not flow enough for that. They might make that if you shoved them on some ungodly large cube Frankenstein shortblock. But then it would run out of breath by 2000rpm.
GM produced a Firefox prototype that made 604hp and 705lbft. But that involved many not stock parts and two turbos. Car sits in the Pontiac heritage museum to this day as far as I know.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Originally Posted by Iroc8t8
638 is the casting number. Should i build this block or should I buy one that's built already?
Avoiding all stories and defamation of a car that likely no longer exists, 638 block is a 4in bore block. You can start there as it's a roller provision block and originally a 350 block. Whether it's still in rebuild-able shape depends on what a good machine shop says. Could be bored 60 over already, you don't know till it's apart.
If its worth building it over a crate depends on goals and budget. More importantly budget.
400hp is capable on a long runner tpi, but takes A LOT of work. And even then it doesn't "look" stock. Stock runners WILL NOT support anywhere close to that. So Cal guys on the boards have some pretty good write ups. Search. If 400 hp is truly a goal, an aftermarket intake (FIRST, hsr, miniram) will be the easiest route. None of those look like a TPI.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
This can go on and on that my step dad is full of it or a 5.0 tpi burned tires to 70mph with stock rear end and about 60-75% tread tires. U think I'm doing this for attention. I've explained myself about the car and it came from a dealer he says. He also told me it wouldn't idle down past 1k rpm. He is very mechanically inclined and to his knowledge about the 86 iroc he says all of this like the car still blows his mind. I was young but he wasnt. He knows what the car looked like from ground up he was about 42 years old. Chevy guy since he was a kid. He has a 65 chevy he built from ground up and an 88 k10 lifted. Not your backyard mechanic guy!!! Just as experienced as most of you guys. My mind is blown just thinking about what it may had in a 5.0. The answer Nobody will ever know. A car that kept ripping transmissions out in it and wasn't from horseplay. Just normal daily driver and every now and then race but what does that matter right. I'm sure I'll get responses that 700r are junk and he must have bought bad ones. I'm sure everybody isnt falling for a 5.0 doing this. That's why it will be out there for somebody is may have gotten one that was red and had different color fenders on it from indianapolis area.
Re: Tpi looked stock but had ridiculous amount of power. How is this possible
Ya ever think maybe your dad knows the truth bit doesn't want to crush one of your fondest childhood memories with him??
No one has said once that your dad was full of it. No one has said that this particular car didn't do what you said. We have just said that it is physically impossible for a STOCK 305, tpi or otherwise to have done what you are claiming. For that car to have done what you claim it was built. The only way to be as quick as you say with a stock motor would be to have a rediculous rear gear ratio, and at that point it prolly wouldn't even do 70 without being past redline in final gear. That leaves everything pointing to it being a built motor. You asked how is it possible that, that car did what you remember, we told you how it would be possible. Then you told us all we were wrong and that it was stock. Facts being facts, and physics being physics, a stock 305 tpi and 700r4 would not break traction at 70mph unless you were passing over an oil slick at that exact moment he gunned it or it had just or was raining.
Sorry, there's no way your stock 305 tpi magically made 3 times as much horsepower as the rest of them. Basically the car was absolutely not stock, or the things you say happened never did.
Now you can accept the information presented to you, and think that we do believe you, and maybe you or your dad's memory of what the motor looked like is a little hazy, which happens to everyone after such a long period of time, or you can think that no one believes you and you somehow had a magical 305 tpi that pulled an extra 400 or so horsepower out of its tailpipe.
Once again, no one is or has said you are lying, we are just saying logically how it did what you say, and are coming to conclusions to fit it in your description as best as you can.
08-07-2015, 10:08 AM
