Question: Replace Q-J with???????

[antique78vette]

I'd like an opinion from all C3 experts with regards to replacing my 78SA L48 Q-Jet with any other type/make of carb without changing the intake
manifold etc, if that is possible??? Taking into consideration not having to do a lot of modifications and without changing out the hood.


All comments, suggestions etc are appreciated.


antique78vette

 

[Vettehead Mikey]

Sure you can change it. But why? You'll gain nothing. A spreadbore Holley will sort of fit kinda.

 

[gmjunkie]

Sure you can change it. But why? You'll gain nothing. A spreadbore Holley will sort of fit kinda.

A Good Q-Jet beats a Holley any day!!

 

[baxsom]

never bad mouth qjets on a corvette forfum. its like badmouthing the spurs in san antonio. still, if you need to change it to a square bore then you should change the intake as well. it just makes everything fit together easier.

when i got my vette the qjet was an tired worn out one from a 350 stuck on the 454. it leaked and dripped.

i didnt have the first clue on how to work on it and no one local would touch it. since holley techs are dime a dozen i decided to change over and never regretted it but to some people here its a horrible sin much like killing babies and kicking dogs.

 

[Vettehead Mikey]

but to some people here its a horrible sin much like killing babies and kicking dogs.

No, I'm just cheap. I'd buy a boat if I was looking for a new way to waste money. Instead, I just stand in the shower and shred $20 bills.

 

[6880 Mike]

...i didnt have the first clue on how to work on it and no one local would touch it...

Knowledge is power.

 

[baxsom]

yes a book, i can read a book on how to do brain surgery but that doesnt make me qualified to do it. id rather give a dyno operator that can tune a holley 200 bucks to get the car set up right than trial and error based on what I read is "supposed" to happen.

but thats just me, i dont do brand loyalty. id rather do what is easiest to just be able to drive. to me that was put on a holley and go to the one of the many local shops that can tune old cars and holleys. more time for driving, less time reading.

 

[gmjunkie]

yes a book, i can read a book on how to do brain surgery but that doesnt make me qualified to do it. id rather give a dyno operator that can tune a holley 200 bucks to get the car set up right than trial and error based on what I read is "supposed" to happen.

but thats just me, i dont do brand loyalty. id rather do what is easiest to just be able to drive. to me that was put on a holley and go to the one of the many local shops that can tune old cars and holleys. more time for driving, less time reading.

I can tune a Holley as good as the next guy,But you just can't beat a good ol Q-Jet as far as staying that way!
I've set up Q-Jets and they go 100,000 miles!! Seems to me that your doing good if you can get a Holley passed 35-40,000 miles
before the floats start sticking or the power valve is leaking!
But then again,I'm kinda partial to a Good Ol Carter AFB too!!

 

[LLC5]

I can tune a Holly as good as the next guy,But you just can't beat a good ol Q-Jet as far as staying that way!
I've set up Q-Jets and they go 100,000 miles!! Seems to me that your doing good if you can get a Holly passed 35-40,000 miles
before the floats start sticking or the power valve is leaking!
But then again,I'm kinda partial to a Good Ol Carter AFB too!!

My opinion also. Q-jet over Holley any day for reliability and driveability. Ditto on the AFB.

 

[73shark]

The good news about a Holley is there are a lot of adjustments. The bad news is there are a lot of adjustments.

 

[douglasamariani]

My opinion also. Q-jet over Holley any day for reliability and driveability. Ditto on the AFB.

I Agree

 

[SPANISHVETTS]

Never had a Q-jet leak

And never had a Holly stay dry for long.

Just for fun why not TBI fuel inject it.

The 454 TBI setup looks a lot like a carb so it does not mess up the looks of the engine bay and the tuning is easy.

I just converted a 75 GMC motorhome to TBI. Easy 2 day job and she starts and runs good on the 455 chip. Picked up the hiway millage from 8.5 to a bit over 10MPG over the same stretch of road from LA to San Diego and back.

But there will be no bragging before we get a chip burnt and see what the average gains or losses are over a thousand or so miles.

 

[spikebot 81]

never bad mouth qjets on a corvette forfum. its like badmouthing the spurs in san antonio. still, if you need to change it to a square bore then you should change the intake as well. it just makes everything fit together easier.

when i got my vette the qjet was an tired worn out one from a 350 stuck on the 454. it leaked and dripped.

i didnt have the first clue on how to work on it and no one local would touch it. since holley techs are dime a dozen i decided to change over and never regretted it but to some people here its a horrible sin much like killing babies and kicking dogs.

I also dumped the q jet and bought the 600cfm edelbrock and the performer manifold. 8000 miles on it and running great no issues. Flame away boys

 

[bucket]

I'd like an opinion from all C3 experts with regards to replacing my 78SA L48 Q-Jet with any other type/make of carb without changing the intake
manifold etc, if that is possible??? Taking into consideration not having to do a lot of modifications and without changing out the hood.


All comments, suggestions etc are appreciated.


antique78vette

..

ignore the holly folk
the smoothest accelerating is the
Carter AFB
now known as the edlebrock..

 

[Vettehead Mikey]

I also dumped the q jet and bought the 600cfm edelbrock and the performer manifold. 8000 miles on it and running great no issues. Flame away boys

Well, not sure why you'd put a 600 cfm carb on instead of your 750 cfm qjet, but hey- have a nice day!

 

[fine69]

I have a q-jet on my Vette and an Edelbrock 600 on my Z-28. Both have been fine carburetors; and relatively easy to adjust.

My q-jet was rebuit from a vendor I found online... works like a charm.... Vette79 (Jeff) also used this vendor to obtain his q-jet. I believe he's been satisfied as well.

I had a Holley years ago. I could never adjust it correctly - I finally blew out the power valve seals. I've stayed away from them since.

 

[bucket]

Well, not sure why you'd put a 600 cfm carb on instead of your 750 cfm qjet, but hey- have a nice day!

.....

sometimes the numbers dont mean much...

how fast is a 3400lb cup car with a 500cfm holly?

the afb always works smoother than the q jet (but i do love the sound ,of the q jet and that hesitation right befor it kicks in) and the hollys are, well, they are great but ..

a rechargeable screwdriver makes changing metering rods quick work, like, two minutes
i used to tune my gto on the side of the road doing country boy dyno tuning
run it wide open then shut it off, read the plug and adjust accordingly.
changing the metering rods and jets is so easy a caveman could do it
if you can read a sprk plug
you will running clean befor you know it
and if you are half as picky as me
you will change the tune for the weather...
have fun

 

[spikebot 81]

Well, not sure why you'd put a 600 cfm carb on instead of your 750 cfm qjet, but hey- have a nice day!

Mikey thats a very good question. Three years ago when I was having problems with the POs rebuilt q jet I searched the boards and was told by many that a 750 aftermarket carb was too big. So dumb ass me listens. Im not regretting the smaller carb matched up with the 882 smog heads. This winter the plan is for new top end and a more realistic carb to match

 

[KANE]

Well, not sure why you'd put a 600 cfm carb on instead of your 750 cfm qjet, but hey- have a nice day!

Actually, for a bone stock L81 engine... it should be plenty. The point is matching components together. A small carb and a small cam would complement each other nicely. The L81 is not set up as a serious performance engine.

Spikebot- building the intake, heads, and carb at the same time are the way to go. I'd think about the cam too.

 

[spikebot 81]

Actually, for a bone stock L81 engine... it should be plenty. The point is matching components together. A small carb and a small cam would complement each other nicely. The L81 is not set up as a serious performance engine.

Spikebot- building the intake, heads, and carb at the same time are the way to go. I'd think about the cam too.

I agree, camshaft matched to heads is a must. I.m in the research stage now. Not a stock motor in this 81 althought it was smog legal car when I bought it.