Best Aftermarket/Knockoff parts for GMT400s

[Boots97]

Hi Everyone,

Long time since a new post, but here it goes...

As we all know, AC Delco parts are the best parts to get for these trucks if we can help it. However, bc these trucks are getting old, GM is making less and less parts for these trucks as time goes by. Fortunately, the aftermarket has helped fill in these gaps of what would be unavailable parts. Unfortunately, there is a lot of subpar quality parts out there as well.

In your opinions, what are some of the best aftermarket/non OEM knockoff parts to buy that are just as good as AC Delco/GM Genuine parts? What are the worst parts as well?

IMO, Dualast and MasterPro parts from AutoZone and O'Reilly's have never let me down. They look and work like OEM parts and no one has ever noticed it being a non GM part at a glance.

The worst parts is Dorman...by far...nothing I've ever bought (except lug nuts) have been complete trash. Radio knobs work, but look nothing like the GM ones. Dorman door handle installed by PO was breaking apart and Dorman hinge pin kits are trash too.

Here's the link for my rant post on Dorman:

Dorman: A possible unpopular opinion

Hi Everyone, I don't know if this is an unpopular opinion per se, but here's my opinion on Dorman parts... @kennythewelder touched on this breifly regarding Dorman door pins, but these kits are GARBAGE! People, please stay away from these things, even the pins are trash. About 6 months ago, I...

www.gmt400.com

 

[Caman96]

To me, it depends on the part. I also consider where part is manufactured. I do prefer GM Genuine/Acdelco parts in general though. Although when I did front end I chose other manufacturers purposely over Acdelco(Pro Forged, Mevotech TTX, SuperSteer, Cognito, Cunningham Machine…). Love NOS parts as well.

 

[454cid]

Well Dorman is something I avoid, but as Caman96 said, it depends on what you're after. No single company makes everything, but often time will market more than what they make. I like buying what a company actually makes. For instance, Gates makes hoses and belts, but they also sell water pumps. The water pumps are just cheap made in China parts they put their name on. I usually buy Gates hoses, but I found out the hardway not to buy their water pumps. The first one only lasted a year or two, and the warranty replacement was obviously made by another supplier. I put it on a shelf, and tried another brand.

 

[HotWheelsBurban]

I was brought up to use OEM parts where possible, which since we were a GM family with a parts store, was AC Delco. Of course this knowledge started 50+ years ago, when you could get everything you need from the warehouses or the dealership parts department. Reading on gmsb.com(the square body trucks forums) I'm remembering things Dad talked about doing on our square body GMC pickups, and the different parts and sources he used.
So for electrical system stuff, and plugs and filters, AC Delco/Delco Remy was our go to. For trailer connection stuff, or add on switches and that type stuff, we used Standard Ignition, and front end parts were always Moog.
Of course this was back in the day, when things were mostly made in the USA (unless you were getting parts for one of those "furrin" cars). And in the 70s and 80s, the companies that handled import car parts mostly sold the OEM or equivalent parts, though the box said Worldparts or Beck/Arnley. I guess you'd say they were distributors? Part of the reason why they had to go with the OEM manufacturers,was many of the makes were bad about making running changes on the production line, or changing something on the part,just often enough for the aftermarket to not want to make them, because they couldn't justify spending retooling $$$ to keep up. Honda was particularly bad about this!
And of course the parts are made all over the world now, and quality isn't as important as it used to be.
I've had good luck with the UMP cap and rotor for the Vortecs, with the brass contacts and the cap vent. But I know that it's not out of the realm of possibility, that I could have a bad or cracked cap on the crew cab, and that's what is causing the rough idling. More likely however,is that it needs a set of plug wires (after 27 years, ya think?), and I know some of the extra separators I installed aren't staying where I put them. And I probably should change the fuel filter too, been more than a year since I replaced it.....
The Precision brand fuel pump on the Burb has been great; that's another thing, like the blower motor on the crew cab,that I didn't know how bad it was, because it wore out so gradually. I also have Precision brand upper control arm assemblies on the Burb, and they seem to be holding up. Back in the day,all I knew Precision had was U- joints... Obviously they have moved into more manufacturing or reselling opportunities. Filters, I still use AC as long as I can get them(on oil filters). The air filter,I will use a Frame, since you can see when it starts getting clogged. The brake pads on the Burb are Wagner, they seem to hold up okay. On a truck that gets driven in city traffic, and stops a lot, it's not unusual to change brake pads every year or two. The other brake components I've replaced on the Burb are O'Reilly's house brand, masterpro or brake best or something like that. They do the job, and they have lifetime warranty.

 

[HotWheelsBurban]

Well Dorman is something I avoid, but as Caman96 said, it depends on what you're after. No single company makes everything, but often time will market more than what they make. I like buying what a company actually makes. For instance, Gates makes hoses and belts, but they also sell water pumps. The water pumps are just cheap made in China parts they put their name on. I usually buy Gates hoses, but I found out the hardway not to buy their water pumps. The first one only lasted a year or two, and the warranty replacement was obviously made by another supplier. I put it on a shelf, and tried another brand.

Yup I forgot about the belts and hoses! Dad always used Gates, and that's what we sold as well. No major problems with them, and we'd get good service from them. And now, the serpentine belts last longer, and the tensioner assembly and idler pulleys are considered "wear parts" i.e. something that gets replaced periodically.

 

[Komet]

In situations where I can't get AC Delco or GM Genuine parts, I have had good results with Standard Motor Products parts. Usually sensors and stuff like that. Never buy the T-Series, always get the more expensive one. I suspect they are the oem for a lot of local parts store brands.

I did Raybestos brand everything front brakes once and it seemed to be as good as OEM to me, wouldn't hesitate to use their products.

I have had very good results with Fel-Pro gaskets of all kinds, I think they're as good or better than OEM.

 

[df2x4]

I try to go with OEM GM/ACDelco (NOS, even better) with most things, but occasionally I will go down a research rabbit hole and try to replace parts with something better than OEM (or equivalent at a lower price, sometimes you can make a good educated guess about who currently supplies GM/ACDelco).

Some good examples of improvements over OEM off the top of my head...

Cunningham Machine door parts. IMO pretty much everything in their catalog for GMT400 doors is better than what came on the trucks.

Raybestos Element3 (EHT369H) brake pads. DOT friction code of HH and around $25/pair on RockAuto, with hardware. They're a significantly more aggressive friction compound than any of the track offerings from EBC or Hawk for a fraction of the price. More info here:
https://www.gmt400.com/threads/ebc-yellowstuff-brake-pads-worth-it.47903/

Dorman (Yes, Dorman actually does make some good things) 800401 heater hose quick disconnect. Made from a better material than the OEM part, recommended by a GM tech.
https://www.gmt400.com/threads/quick-disconnect-fitting-on-heater-inlet-hose.51460/post-1137101

 

[Boots97]

To me, it depends on the part. I also consider where part is manufactured. I do prefer GM Genuine/Acdelco parts in general though. Although when I did front end I chose other manufacturers purposely over Acdelco(Pro Forged, Mevotech TTX, SuperSteer, Cognito, Cunningham Machine…). Love NOS parts as well.

All great choices! I do love Cunningham machine bushings and one day I plan on buying their steering shaft once my old one wears out. Mevotech TTX tie rods are awesome and I would've used them if I knew what I know now. I have MasterPro tie rods on rn and they're holding up just fine after 10K miles.

Don't worry, I love scanning eBay for NOS GM parts too. Aftermarket is what I go to if the forum approves or NOS isn't available anymore.

 

[Boots97]

Well Dorman is something I avoid, but as Caman96 said, it depends on what you're after. No single company makes everything, but often time will market more than what they make. I like buying what a company actually makes. For instance, Gates makes hoses and belts, but they also sell water pumps. The water pumps are just cheap made in China parts they put their name on. I usually buy Gates hoses, but I found out the hardway not to buy their water pumps. The first one only lasted a year or two, and the warranty replacement was obviously made by another supplier. I put it on a shelf, and tried another brand.

I've learned that too over the years. Companies "make" some parts and "sell" others while someone at the backdoor is actually making them. Granted, I doubt that all AC Delco/GM Genuine parts are made by GM as I've had parts made in Canada, the US, Mexico, and China, albeit the QC is probably stronger with a name like AC Delco attached to it. Never had an issue with any AC Delco/GM Genuine part so far though.

 

[Boots97]

I was brought up to use OEM parts where possible, which since we were a GM family with a parts store, was AC Delco. Of course this knowledge started 50+ years ago, when you could get everything you need from the warehouses or the dealership parts department. Reading on gmsb.com(the square body trucks forums) I'm remembering things Dad talked about doing on our square body GMC pickups, and the different parts and sources he used.
So for electrical system stuff, and plugs and filters, AC Delco/Delco Remy was our go to. For trailer connection stuff, or add on switches and that type stuff, we used Standard Ignition, and front end parts were always Moog.
Of course this was back in the day, when things were mostly made in the USA (unless you were getting parts for one of those "furrin" cars). And in the 70s and 80s, the companies that handled import car parts mostly sold the OEM or equivalent parts, though the box said Worldparts or Beck/Arnley. I guess you'd say they were distributors? Part of the reason why they had to go with the OEM manufacturers,was many of the makes were bad about making running changes on the production line, or changing something on the part,just often enough for the aftermarket to not want to make them, because they couldn't justify spending retooling $$$ to keep up. Honda was particularly bad about this!
And of course the parts are made all over the world now, and quality isn't as important as it used to be.
I've had good luck with the UMP cap and rotor for the Vortecs, with the brass contacts and the cap vent. But I know that it's not out of the realm of possibility, that I could have a bad or cracked cap on the crew cab, and that's what is causing the rough idling. More likely however,is that it needs a set of plug wires (after 27 years, ya think?), and I know some of the extra separators I installed aren't staying where I put them. And I probably should change the fuel filter too, been more than a year since I replaced it.....
The Precision brand fuel pump on the Burb has been great; that's another thing, like the blower motor on the crew cab,that I didn't know how bad it was, because it wore out so gradually. I also have Precision brand upper control arm assemblies on the Burb, and they seem to be holding up. Back in the day,all I knew Precision had was U- joints... Obviously they have moved into more manufacturing or reselling opportunities. Filters, I still use AC as long as I can get them(on oil filters). The air filter,I will use a Frame, since you can see when it starts getting clogged. The brake pads on the Burb are Wagner, they seem to hold up okay. On a truck that gets driven in city traffic, and stops a lot, it's not unusual to change brake pads every year or two. The other brake components I've replaced on the Burb are O'Reilly's house brand, masterpro or brake best or something like that. They do the job, and they have lifetime warranty.

My Papa (Dad's Dad) was a Ford Engine/Transmission Tech for 43 years. He always preached about using OEM parts. I didn't listen and I always bought the cheapest crap that AutoZone/O'Reilly's had. I did that with my 2007 Ford Taurus and it worked fine. I bought this truck and now I've learned how many trash parts there are out there. Now I've learned my lesson (and wasted a few bucks too) and also try to stick to OEM when possible.

Honda's are overall very good cars, but I agree the way Honda does change things up way too much. Their transmission fluid is also proprietary to their transmissions as well.

I would've bought the UMP Cap and Rotor had I not needed my truck on the road ASAP. Looks like a great deal and I plan on buying a set as a backup since caps and rotors are known to go bad in these trucks.

I didn't know precision made anything else other than U joints either. I recently pulled the eBay steel driveshaft out of my truck and re replaced it with my original aluminum driveshaft with a precision 448 conversion U joint since I got a 14 bolt swapped into it.

Masterpro BrakeBest parts are good too. I have wheel cylinders in my truck and they hold up just like the originals.