Jump to content

Ratings on a 98 Vortec 350

98silvz71

By 98silvz71
in Ask A GM Technician

Recommended Posts

98silvz71 Enthusiast

98silvz71

Posted
Posted

What are the Hp and Torque ratings on a 98 Vortec 350? I have heard a lot but I am not for sure. I just want what the engine is rated for. I also have a hard time stopping this truck even with new brake pads. The dealer says everything is ok. Its just "normal'' Is it possible to change the booster over to the Hydro-Boost like on the newer trucks. My steering is messed up. It is like it almost slips around corners and when the truck isn't moving it doesn't turn.

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted

> What are the Hp and Torque ratings on a 98 Vortec 350?

 

Not a clue.

 

> I also have a hard time stopping this truck even with new brake pads.

 

Rotor finish is critical. Were the rotors refinished? They should have practically a mirror finish. Also, brakes on the older trucks just weren't that impressive.

 

> Is it possible to change the booster over to the Hydro-Boost like on the newer trucks.

 

See answer 1.

 

> My steering is messed up. It is like it almost slips around corners

 

It's almost certainly a bad steering position sensor.

05Silverado81 Enthusiast

05Silverado81

Posted
Posted

I also have a 98 350 vortec, the HP rating on that truck is 255HP, not sure about the torque. The brakes on mine are also the same way, the brakes on those years just plain suck!

Mr. Smith Enthusiast

Mr. Smith

Posted
Posted

First off I would change the EVO sensor as it sounds like it is wasted. When it goes out is give full pressure to the power steering and all times. It makes the ruck steering verry sensitive and normal road speeds. The part is around 60 dollars at GM. But if you have a car parts place that can order motormite/dorman the aftermarket part is around 29 bucks. Also try rockauto.com it is there alot cheaper.

 

You really didn't give alot of info on anything else done to the brakes. Nor was mileage given on the truck. Hydro-Boost isn't the answer to your problem, proper diagnosis is. Tell us more and lets see if we can help you.

 

What are the Hp and Torque ratings on a 98 Vortec 350?  I have heard a lot but I am not for sure.  I just want what the engine is rated for.  I also have a hard time stopping this truck even with new brake pads.  The dealer says everything is ok.  Its just "normal'' Is it possible to change the booster over to the Hydro-Boost like on the newer trucks.  My steering is messed up. It is like it almost slips around corners and when the truck isn't moving it doesn't  turn.

 

 

 

98silvz71 Enthusiast

98silvz71

Posted
  • Author
Posted

Sorry about that. The mileage on the truck is just now 118,000. The rotors were refinished by the guys down at O'Reilly Auto Parts. The pads were brand new with about 12,000 on them I have had GM take a look at the rear drums to make sure that everything is ok. They said that the drums are fine, the pads are fine, the valve is set right. I even asked them if they would set the rear brakes to take more fluid because most of the braking is coming from the front discs. And I was just wondering if Hydro-Boost could help since it pumps up the vaccum pressure for heavier loads. I am sorry if I don't know everything about every part. If you need more information just tell me and I will get it.

Mr. Smith Enthusiast

Mr. Smith

Posted
Posted

How is the brake pedal? Does it seem to go down to the floor? Does it feel mushy? My guess is with those miles the master cylinder is just about gone. Also if you drive alot on the highway the rear shoes may require adjustment. If everything is right with the shoes and shoes then there is only 2 other items NOT covered and they are the master cylinder and vacumn booster. I bet one or the other is junk.

 

There is no user adjustment of the proportioning valve unless you have an aftermarket one installed so if they told you otherwise I would go to another dealer.

 

 

 

Sorry about that.  The mileage on the truck is just now 118,000.  The rotors were refinished by the guys down at O'Reilly Auto Parts. The pads were brand new with about 12,000 on them  I have had GM take a look at the rear drums to make sure that everything is ok.  They said that the drums are fine, the pads are fine, the valve is set right.  I even asked them if they would set the rear brakes to take more fluid because most of the braking is coming from the front discs.  And I was just wondering if Hydro-Boost could help since it pumps up the vaccum pressure for heavier loads. I am sorry if I don't know everything about every part. If you need more information just tell me and I will get it.

 

 

 

98silvz71 Enthusiast

98silvz71

Posted
  • Author
Posted

How is the brake pedal? Does it seem to go down to the floor? Does it feel mushy? My guess is with those miles the master cylinder is just about gone. Also if you drive alot on the highway the rear shoes may require adjustment. If everything is right with the shoes and shoes then there is only 2 other items NOT covered and they are the master cylinder and vacumn booster. I bet one or the other is junk.

 

There is no user adjustment of the proportioning valve unless you have an aftermarket one installed so if they told you otherwise I would go to another dealer.

 

 

The brake pedal goes down a ways before you can feel it touch the rotor. Not to the floor but pretty close. Actually it is preetty mushy come to think of it. I have done what they told me to do to adjust the rear brakes which is shift into reverse and pump the brake pedal because the shoes are self adjusting. It didn't really help much, it seemed to fad away after just a short time. When you said something about the EVO what were you talking about? I am not familiar with all of the terms and stuff. I try my best.

Mr. Smith Enthusiast

Mr. Smith

Posted
Posted

Change the master cylinder. I bet it is the original. Flush the brake fluid as well. The EVO sensor is at the bottom of the steering column.

 

Actually to adjust the rear shoes you have to drive in forward and reverse depressing the brake pedal in each direction to properly adjust the rear brake shoes.

 

 

How is the brake pedal? Does it seem to go down to the floor? Does it feel mushy? My guess is with those miles the master cylinder is just about gone. Also if you drive alot on the highway the rear shoes may require adjustment. If everything is right with the shoes and shoes then there is only 2 other items NOT covered and they are the master cylinder and vacumn booster. I bet one or the other is junk.

 

There is no user adjustment of the proportioning valve unless you have an aftermarket one installed so if they told you otherwise I would go to another dealer.

 

 

The brake pedal goes down a ways before you can feel it touch the rotor. Not to the floor but pretty close. Actually it is preetty mushy come to think of it. I have done what they told me to do to adjust the rear brakes which is shift into reverse and pump the brake pedal because the shoes are self adjusting. It didn't really help much, it seemed to fad away after just a short time. When you said something about the EVO what were you talking about? I am not familiar with all of the terms and stuff. I try my best.

 

 

 

 

98silvz71 Enthusiast

98silvz71

Posted
  • Author
Posted
Change the master cylinder. I bet it is the original. Flush the brake fluid as well. The EVO sensor is at the bottom of the steering column.

 

Actually to adjust the rear shoes you have to drive in forward and reverse depressing the brake pedal in each direction to properly adjust the rear brake shoes.

 

I'll try that, it is the original. Thanks for the help with the EVO sensor. I didn't know that about the rear shoes. The guys at GM only told me to go in reverse because that is what the manual states to do. Thanks for the help Mr. Smith

  • 1 month later...
Zoltar Enthusiast

Zoltar

Posted
Posted

I agree with their suggestions. You really should start with changing your brake fluid. You WILL notice a big difference if it hasnt been changed for a while. I added rear disc's to my 96 Sub and at the same time I put in a Corvet (not sure what year) master cylinder. The brake feel is now much tighter. The mush is gone.

 

I think the 97-99 Vortec was 255hp 330 torque and 96 was 245hp

linust New Member

linust

Posted
Posted

I'd also check the self-adjusters on the rear brakes--if they freeze up (like they do when you tow a boat and launch/retrieve in saltwater) the rear brakes will be used less and less.

98silvz71 Enthusiast

98silvz71

Posted
  • Author
Posted

Thanks for all of your suggestions. I turned the rotors again and I have about 50% of material left on the pads. The rear drums are just fine. I also found that the intake manifold gasket was bad and I think that is where the vacuum pressure went. I replaced it and the pedal is less squishy but there is still some. I will try changing the brake fluid and maybe the booster if it is still squishy. In the future I will change the brakes to SSBC 4- wheel disc brake kit.

98silvz71 Enthusiast

98silvz71

Posted
  • Author
Posted

The bad steering actually wasn't the steering sensor. I replaced it and it still was bad and then it started sqeaking in the front end. I took it to GM and they found the problem right away. The pitman and idler arms were messed up so it took about 2 hours and the steering was just fine.

Zoltar Enthusiast

Zoltar

Posted
Posted
Thanks for all of your suggestions.  I turned the rotors again and I have about 50% of material left on the pads.  The rear drums are just fine.  I also found that the intake manifold gasket was bad and I think that is where the vacuum pressure went. I replaced it and the pedal is less squishy but there is still some.  I will try changing the brake fluid and maybe the booster if it is still squishy.  In the future I will change the  brakes to SSBC 4- wheel disc brake kit.

 

 

 

 

 

Make sure SSB does not send you the kit with the Thunderbird rear calipers. I have had nothing but trouble with mine.

98silvz71 Enthusiast

98silvz71

Posted
  • Author
Posted

I've heard that before but I had a buddy call them and tell them and they corrected the error. Didn't they do that for you?

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.3k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,716
    Total Members
    8,960
    Most Online
    BDS my HD
    Newest Member
    BDS my HD
    Joined

  • Who's Online   1 Member, 0 Anonymous, 532 Guests (See full list)

  • Latest Articles

  • Posts

    • BDS my HD
      Brand new to this forum. Questions about re-gearing my 26’ HD

      By BDS my HD · Posted

      Hello hello looking forward to expanding my knowledge of the 2026 2500 HD that I just bought.   Truck has 3500 miles on it four-wheel-drive crew cab and I’m about to put a 6 1/2 inch BDS lift on it 18 x 10 -25 offset with 37’s   Already have the wheels and tires just waiting on the lift install in about three weeks   Question what surprises am I not gonna be happy with?  I’m not new to lifted trucks so I know that acceleration towing gas mileage all that is affected..   Question is those of you that have this truck this powertrain with a 10 speed Allison and have done the mods that I’m doing,,, how bad is it? Is that Allison constantly gonna be hunting for the right gear to go into? And what about towing, acceleration, fuel consumption as mentioned?    Lastly how come I can’t find any ring pinion gear set up for these axles and when could I expect to see them?   I apologize if there’s any typos I’m doing speech to text on my iPhone.    
    • linc45bn
      2013 2500HD 6.0L intermittent no crank no start

      By linc45bn · Posted

      I've got a 2013 2500 6.0L Flexfuel. Drove the truck earlier today with no issues. Went to run an errand tonight and noticed key fob wouldn't work. Figured battery was dead, so replaced fob batter. Still wasn't working. Grabbed my other set of keys with the other fob and that one wasn't working either. So I manually unlock truck and insert key. Interior lights come on, dashboard lights up, turn key and truck starts. Turn truck off, like a moron, and try starting again. This time no crank, no click, no nothing. Lights still come on and dash lights up, but now I'm getting a service 4wheel drive, service tire monitor, etc. Check voltage on battery and Im showing 12.2v. Throw my battery charger on it and give it 15 mins and try starting again. But still no crank no start. Decide maybe its a bad battery, run to autozone grab a new one and put it in. Same issue. Disconnect battery and let it sit for 15 mins. Try again and still nothing. I had managed to roll the windows down earlier as its a humid night, but now I can't get them to roll up. Power locks are also not working now. Then randomly I try the key again, and it fires right up. Immediately I roll up the windows as we have nothing but rain forecast this week. I shut it back off wait 30 seconds and start up again. Worked a 2nd time. So turn it off, start putting things back together. Try one more time, and back to no crank no start. And now the car alarm starts going off. Had to disconnect battery and leave it that way for the night as I don't think my neighbors would appreciate my alarm going off again tonight. Any thoughts or help would be appreciated. 
    • Grumpy Bear
      first oil change - 2026 2500HD gas

      By Grumpy Bear · Posted

      No one will care for you like you care for you. Do what you can for as long as you can. IMHO of course. 
    • Grumpy Bear
      Oil Consumption

      By Grumpy Bear · Posted

      How about them NICKS!!! 
    • Peoplemvr
      GMC 1500 Illuminated Front Grill Emblem REPLACEMENT.

      By Peoplemvr · Posted

      Hi there.  Long time lurker, first post.    i have read the previous posts regarding the water ingress problem with this emblem.  I bought my 1500 SLT the  summer of 2025 new and after reading the MANY problems with these emblems failing I decided to install one anyways.  As per a YouTube video, I sealed ( or tried to) this sign with silicone sealant around the outer perimeter joint and the holes that were already somewhat sealed on the rear plate of the emblem.  And installed the connector assembly using dielectric grease on the connectors. The installation looked great and worked well for about 4 months……then FAILURE.  Grrrrrr…… I live in the great white north and wash my truck weekly in an automatic car wash  to keep the salt off.  Let me tell you that removing the old, failed emblem is a whole different animal than removing the OEM individual letters without removing the grill assembly. Mainly because the illuminated logo is built differently than the original letters which  you can remove the red surface lettering with a knife or some kind of blade which gives access to the tabs which hold the logo onto the grill. So I had to essentially destroyed the old emblem to remove it. Doing so killed my chance of doing somekind of autopsy on the failed , old logo.  But there was plenty of water inside when I ripped it apart.  Prior to installing the new assembly I tried it with the old harness and it works fine.   Does anyone have any insight as to where the water is getting into this emblem? I intend to seal the new logo with slow curing epoxy this time around using a syringe.  I think this newer emblem may be an updated unit which I hope GM got the vendor to fix. It has an October 2025 date on it.    If this one  fails,  I am just going to revert back to the non-illuminated letters….AFTER PULLING THE GRILL.    Any thoughts on sealing with epoxy would be appreciated. Thx!   Doug  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...