Seacoot,
Go back and read the thread in sequence and I think you'll see that there has been an opportunity for learning here, and you may have been mistaken about sarcastic responses directed at you. I am new to the forum myself and a first time vette owner and have learned much here from many helpful people and I thank them.
Many people,-----many different ideas, use what works for you, and return the help where you can. No need to leave and miss out on so much knowledge.
Brian

 

Seacoot -
My apologies for any offense. I just love jabbing at Gordon (Commander47) and yanking his chain - he really gets entertaining...

If you're still around, here are some thoughts:

If you still have your original L82 Q-Jet, note that its one of the rare high performance 800 cfm carbs. If it's undamaged, not commercially rebuilt, and unaltered, it can be rebuilt and set up to equal or exceed the performance of any aftermarket carb. The SA carb will not outperform that Q-Jet, if the Q-Jet is correctly set up. On the other hand, any brand carb that is properly and correctly set up will outperform any other brand of carb that is damaged or incorrectly set up.

If your Q-Jet is damaged, non-original, or altered, changing carbs may be a reasonable alternative.

Keep in mind that the SA Holley is a square-bore carb, so you cannot use it on your stock manifold without an adapter. The overall height of a Holley is the same as a Q-Jet, but the adapter will add 3/4" of height. You can simply crunch up some tin foil, lay it in a ball on your air cleaner lid, and slam the hood. This will then show you how much hood clearance you have, and you can see if you can run the 3/4" increase in height.

If not, you have to either swap the intake manifold over to a square-bore aftermarket, or you can run a drop-base aftermarket air cleaner with the Holley. Your third option is to use a spread-bore Holley, which will bolt up to your stock manifold.

A correctly set up Holley will run better than a badly set up Q-Jet. The opposite is also true. Neither carb, properly set up, offers any performance advantage over the other on the top end. I advise my customers to run the carb they're most comfortable with setting up and tuning. If you are relying on a mechanic to do your work, and if he is not familiar with Q-Jets, the Holley swap may be good. But don't trade in your stock carb (if the carb you have is the correct, original carb).

...I'll still pay postage for it if you don't want it...

Good luck with the project!

Hey Mike: I thought you were the sarcastic idiot who chases people away. Does this mean that I can join your Club now, or do I have to demonstrate consistent and ongoing ability...?

Lars

 

You're doing just fine. Rather than just confining myself to sarcastic or condescending comments which are the two leading observations, I'm trying to broaden my scope to encompass rude, effete, vague, inappropriate, unnecessary, obtuse, and in particular, 'dismissive' all to fall under the bigger umbrella of 'Mr. Nasty'.

I think I've won the title at least 10 years running. Think you're up for the challenge?

Got to risk losing your 'Mr. Grumpy' privileges if you are.

 

Lars is a good guy, and the grand high priest pooh Bah of the Q jet. If anyone can fix it, he can.

He was willfully, and deliberately, planting a bayonette in my back and twisting it.......just for fun.

If anyone was being curmudgenly and sarcastic, it was me. (I learned it from Mike)

But I really do hate Q junks.

 

This place cracks me up. Hopefully, Seacoot comes back and sees some humor in it...
Lars

Mike & Commando: I didn't know you guys knew so many 3- and 4-syllable words...!

 

I got a thesaurus for Christmas. All these years I thought that was a kind of dinosaur.

 

I didn't realize a 17059228 was an 800CFM quad. I thought all of the late 70's Chevies were 750.

Hmmmm...

 

Guys,
I know I'm new here, but it's hard not to see the humor here.
Brian

 

Seacoot - there are some butt-heads here, but Lars ain't one of them. Regarding carbs, either will work. I guess what Lars and others are saying is that Q-Jets have a bad rap, which is simply not based in truth. Mostly by people (mechanics?) who do not understand them.
You wanna see crap? Check out oil threads or maybe thermostat threads. And there are always knuckleheads who bash the newbie questions.
I suggest you hang around for the entertainment value alone, and there is a ton of knowledge to be had. And a bunch of great Vette heads to swap ideas with.
Not to mention the cars... There is a Lars Q-Jet on this old Plane Jane Roadster. And it shreads!

 

The Q-Jets used on the "High Performance" Chevy engines in the mid/late 70's (if you can call them that...) were 800 cfm carbs. Also, the Pontiac carbs of that era are 800 cfm - even the ones Pontiac used on the 350. Here is a listing of the carb numbers I have personally verified to be 800 cfm Q-Jets. There are likely others, but these are the ones I have actually visually verified to be the hi-flow carbs:

17056202 CHEV 76 350 CAMARO FED A/T
17056203 CHEV 76 350 CAMARO FED M/T
17057211 CHEV 77 HIGH PERF A/C & NON-A/C VETTE
17057274 PONT 77 400 FED LEMANS, GP, 'BIRD, "B"
17058241 BUICK & PONT ELECT/LEMANS 78 350 A/T
17058276 PONT 78 (EARLY) 400 FIREBIRD, A/T FED
17058278 PONT 78 (LATE) 400 FIREBIRD A/T FED
17059210 CHEV 79 VETTE L-82 H.P. NON-A/C AUTO
17059211 CHEV 79 VETTE L-82 H.P. A/C 4-SPD
17059228 CHEV 79 VETTE L-82 H.P. A/C AUTO

Since they made them in 77 and 79, you can bet that there are '78 versions as well - I just haven't actually seen one yet.

Lars

 

The group on the C3 forum is child's play compared to the C6Z06 forum-you would not believe that crowd over there….sorry to digress

 

Thanks - I have a 17058228 on my 78, the next time I have it off the car I'll have to check for the "bump".

Would these be single MAB like the big Edelbrock M4Ms, or dual MAB like the bulk of the passenger cars M4Ms? (my 8228 is a dual MAB, one in the airhorn and one in the tower in the main body)

 

Thanks to all that commented on this post and those who sent a PM. I really do like all the great info here. (Lars) it is nice to understand you sense of humor. I do get that now. No harm no foul. Thank you for the info which now makes my decision harder. My Q-Jet runs perfect and the only reason I considered a Holley was for possible performance gains. I think at this point I will not fix it if it aint broke.

 

Hey Commando -
I like that one - can I use that for my title..?

Coot -
Good to see you back. If you have any issue with that Q-Jet, just send it out and I'll test it and correct it if needed.

Lars
Grand High Priest Pooh Bah of the Q-Jet

 

Thank you very much

 

If you REALLY want a Holley because your friend is some Holley master tuner, Go with a 4175. it will bolt on with no modifications.

 

The myth that a Holley makes more power than a Qjet has been around for at least 45 years, so it's been handed down for at least 2 generations of hot rodders. That tends to make it 'true' no matter how many back to back tests prove that it's not.

 

I would not call that a Plane Jane. That is one nice Vette

 

It's good to have to back.

In all the hub bub, your original post kind of got hi-jacked.

A couple of things you need to remember.

1. A Q junk may be capable of 750, 800 or on some trucks even 850 cfm. That does't mean they are set up to use it, nor are they even capable of doing it in from the factory form.

"These are a one carb body fits all" carburettor. They were designed to run as lean and gas miserly as possible with stock applications. On a stock car with a new Holley you will be dumping more fuel into the engine. Hence, more power instantly. There are others, but that is the main one.

Will a q junk do that? Sure, but you have to send it to the grand high pooh bah of the q junk to have it tuned. If you do that, you defeat the purpose of the q junk. Why not just get a performance carb from the beginning?


2. You will really begin to notice the changes with your Holley if you change out the intake to a square bore, dual plane like the Edelbrock Performer series or similar.

3. I would not buy a spreadbore carb if you have any plans of upgrading the manifold. You will be severely limiting your choice of carbs. Whether you go with a Holley or not, a square bore manifold can take a huge choice of carbs, the spreadbore cannot.

4. Q junks are not that difficult to figure out. BUT, they are a huge PITA To make them perform requires TLC, parts are scarce and your choices are limited.

5. I get a kick out of guys who are willing to pay hundreds if not thousands for a "numbers" appropriate q junk carb. For example, the 850 cfm on trucks is the same carb on performance vettes.

The numbers just don't say "vette". The truck carb is much cheaper. And remember, since one size fits all, the grand high pooh bah can tune just about any q to any purpose.


Finally, if you keep it stock, the q is probably fine. If you plan to hot rod the car AT ALL, (ie, new manifold) the Holley Streeet Avengert is an EXCELLENT choice.

 

Wow- just keep drinking that koolaid. It seems to have you convinced.