Why everyone carb swapping?

[L31MaxExpress]

The guy has some valid points but he was comparing the T-quad to the old design Q-jet. They made major improvements to the Q-jet in the mid to late 70's. Better boosters,secondary air bleeds to better mix the secondary fuel and the primary's were adjustable through a hole in the top of the carb. If you blow that picture up of the carb on my 355 you will see the edge of an 1/8" pipe plug under the air breather gasket. The carb came from the factory with an aluminum plug driven into that hole. When I set these carbs up I tap the hole with an 1/8" pipe tap and put those plugs in so when tight they sit flush with the top of the carb. I change the special adjuster screw with a flathead phillips screw. I carry a special tool that I made in my glovebox that has a allen wrench on one end and a phillips screwdriver on the other. I can pull over, pop the breather off, break out my little too, back the plug out, turn the tool over and make an adjustment then put it all back without even shutting the motor off. It took me longer to type all this than it does to adjust primary fuel mixture. Adjusting the secondary's is just how he explains it but I don't recommend doing that with the motor running.

No need to change the adjuster screw. Just grab a double ended ac shrader valve tool.

 

[L31MaxExpress]

The later design Q-jet has an aneroid cavity that has a plastic bowl that sits down into it. Fuel goes around that bowl, not into it. Taking that plastic bowl out doubles the float bowl volume. There are high flow float valve seats that keep fuel flowing into the carb under hard demand. I have never seen the float bowl in a Q-jet go dry with a good fuel pump. I did have a problem with that carb once with it consistently flooding over and it turned out to be a brand new fuel pump that was putting out 11psi. 5psi is absolute max for a Q-jet. They need flow, not pressure. These TBI pumps with a return type regulator set at 3-4psi are the cats @ss for feeding a Q-jet.

TBI sending unit and pump is what I had on my G20 van with the Q-Jet.

 

[Sean Buick 76]

I’m not only a carb lover I also love the LS style EFI. The TBI is likely the most reliable setup to this day. The Vortec is the only one I won’t touch.

Here’s my next door neighbour teaching helping Mr Richard’s teach people how to tune Holley EFI on boost. His Chevelle is currently apart for a new twin turbo setup he’s fabricating and he’s shooting for 1400 HP with twin 62mm. One of his customers cars was a 540 inch twin setup that was 2800 Hp, insanity!

Dont mind the annoying guy whos filming he’s the mascot:

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I’m a Q jet fan for anything under 450 HP, I’ve got all the books about them. I’ve had great luck with both “Q power” and “Everyday Performance” for good quality custom rebuilds. Everyday recently released a new book on the topic, and Q power has amazing YouTube how to videos. Both are family businesses.

CSU in California does my Holley 750 CFM blow through carbs. We’ve been over 1000 HP to the tires on a 5.3 using my E-85 on boost. He did my pump gas carb as well and it was flawless right out of the box, dropped it on, set the idle mix and drove to the dyno. Given I run at a certain altitude, summer only, but they have been amazing to work with. Kevin from CSU took the time to stay on the phone with me during my dyno runs to help verify things were happy and then I never had to touch the carb after that. From idle to 7000 RPM, from cruising in vacuum to 20 psi the AFRs stay in range. That one is going on my 92 truck as my turbo buick is going to E-85.

 

[Sean Buick 76]

There were some larger Quadrajets. Cadillac Quadrajets were 795 CFM and were a lot more common than the 805 CFM Buick Quadrajets. I think they're all hens' teeth now, though.

I’ve hoarded a few of the later style 800 CFM versions. I even snagged an Edelbrock Q jet that was rated for 850 CFM however after further inspection I believe they inflated the rating as the bores are the same diameter as my 800s.

 

[Sean Buick 76]

I don't think any carbed engine could pass Commiefornicate's emissions standards for HC and NOx and still beat an EFI in every day driving.

Not to the level of commiefornia testing however my 76 Buick century passed a smog test in Vancouver BC Canada in about 2002. It had a 10:1 70 model engine with a mild TA-212 cam, factory exhaust, charcoal canister, all other emissions junk on it, and a fresh Q jet. Swapped on headers and duals right after the testing and moved away from Vancouver to Alberta and no more testing.

 

[Scooterwrench]

Edelbrock Q jet that was rated for 850 CFM however after further inspection I believe they inflated the rating as the bores are the same diameter as my 800s.

Did Edelbrock get it right with their repops? I've never had one in my hands. Did you see that maybe they thinned the throttle shafts and flushed up the screws?

 

[Supercharged111]

The later design Q-jet has an aneroid cavity that has a plastic bowl that sits down into it. Fuel goes around that bowl, not into it. Taking that plastic bowl out doubles the float bowl volume. There are high flow float valve seats that keep fuel flowing into the carb under hard demand. I have never seen the float bowl in a Q-jet go dry with a good fuel pump. I did have a problem with that carb once with it consistently flooding over and it turned out to be a brand new fuel pump that was putting out 11psi. 5psi is absolute max for a Q-jet. They need flow, not pressure. These TBI pumps with a return type regulator set at 3-4psi are the cats @ss for feeding a Q-jet.

Does that thing serve a purpose? I feel like I remember this cage dealie being inside the bowl now but I also like to remember stuff incorrectly sometimes as well. The pump I have on now (mechanical) pushes like 9 at an idle which I've never liked. I thought though once you got into a larger needle and seat that they become even more sensitive to fuel pressure, i.e. that larger needle is super easy to push off the seat.

 

[Pinger]

Also worth remembering that injection systems are immune to fuel surge that can occur in carb float chambers. Not so important to the likes of us but a non-starter in say, a F1 car cornering at 4-5G.

 

[Sean Buick 76]

Did Edelbrock get it right with their repops? I've never had one in my hands. Did you see that maybe they thinned the throttle shafts and flushed up the screws?

I would have to pull it from the box and compare it to a regular Q jet I’m not sure? Maybe that’s how they got the 50 CFM rating increase? Ah too many boxes of carbs here which one is it lol??? Of course I have the original edelbrock box but it has another carb in it lol .

 

[Drunkcanuk]

I’m not only a carb lover I also love the LS style EFI. The TBI is likely the most reliable setup to this day. The Vortec is the only one I won’t touch.

Here’s my next door neighbour teaching helping Mr Richard’s teach people how to tune Holley EFI on boost. His Chevelle is currently apart for a new twin turbo setup he’s fabricating and he’s shooting for 1400 HP with twin 62mm. One of his customers cars was a 540 inch twin setup that was 2800 Hp, insanity!

Dont mind the annoying guy whos filming he’s the mascot:

xc_hide_links_from_guests_guests_error_hide_media

I’m a Q jet fan for anything under 450 HP, I’ve got all the books about them. I’ve had great luck with both “Q power” and “Everyday Performance” for good quality custom rebuilds. Everyday recently released a new book on the topic, and Q power has amazing YouTube how to videos. Both are family businesses.

CSU in California does my Holley 750 CFM blow through carbs. We’ve been over 1000 HP to the tires on a 5.3 using my E-85 on boost. He did my pump gas carb as well and it was flawless right out of the box, dropped it on, set the idle mix and drove to the dyno. Given I run at a certain altitude, summer only, but they have been amazing to work with. Kevin from CSU took the time to stay on the phone with me during my dyno runs to help verify things were happy and then I never had to touch the carb after that. From idle to 7000 RPM, from cruising in vacuum to 20 psi the AFRs stay in range. That one is going on my 92 truck as my turbo buick is going to E-85.

That was a cool video, couldn't have picked a colder day to do it!! Lol
Neat seeing "our little city" with cool stuff going on. May have to look up the course they put on. It may come in handy in the next few years for some reason, LOL.
Thanks for sharing that. Going to check out the channel.