OK I am going to take the plunge and buy a new carb so please do not try and tell me about rebuilding my current one.

My dilema is this which carb to buy with the following constraints, I will be replaceing the engine in the winter and the inlet manifold as well, I don't want to spend more than $350ish (less is better)I don't mind if I have to replace the gas pump to cope with the carb demands and I want to be able to use it on my current engine, I also really do not mind what make it is as long as it is good.

So what should i choose Make/Model and pump Make/model if needed.

All advice gratefully recieved.


Gary
76 Vette

To answer your question, there are several questions.

First, how is the engine built, or better, how will it be built in the future. That will determine what carb.

Second, how are you going to drive it? Cruise, Drag race, Track? Let us know.

Hi Ken

As yet the engine is obviously unkown but it and the carb fall into the same catagory i want a FAST street car, i shall not be racing or dragging, just driving fast when i can (within legal limits of course )

Gary

I know others will disagree, and that's okay.
But for a street car, fast but not on the track, and stock or mildly built, I would use the Qudra-jet. It has all the CFM you need wide open, and gets better low rpm response and fuel mileage. Also know as a spread bore.

The Hollys etc. are a bit better for drag racing, but sometimes low end is not as responsive due to larger primary bores. When the engine has a stout somewhat lumpy camshaft, higher comression, etc and has a rough or higher than normal idle, these work as well, or better. Even for (mean) street use. In those cases the carb is moving enough air due to higher idle, the small primary does not matter. Then the primaries and secondaries are more ballanced, and the transition is a bit more even, giving a slight edge.

So again, you need to decide what the final engine will be. You don't need to be exact, just have an idea.

Don't go too big. That is a common mistake, and performance suffers. Most street applications don't need more than 650/700 CFM. Not even the mean ones.

AfterShark, jump in here anytime.

|UPDATED|9/15/2004 7:59:16 PM (AZT)|/UPDATED|

JagVette said: OK I am going to take the plunge and buy a new carb so please do not try and tell me about rebuilding my current one. Gary 76 Vette

Im detecting a pattern with you

anyway... if you want a quadrajet type carb... get either the holley or edelbrock NEW replacements.

dont goto autozone and get the holley rebuilt q-jet.. 4 out of 5 of them are junk right out of the box..

dont let anyone talk you into a mech sec carb... they are way too finicky for a novice.. unless you know how to tweak your engine to perfection youll hate a mech sec carb.. I would even go so far as to say.. dont use a mech sec carb on anything under 425 gross hp unless you having a mechanic living with you.

dont go too big.. I see morons all the time who buy 850 cfm carbs and have to castrate the carb to work on their low volumetric efficiency engine.

personally I like the road demon 625... but this requires changing to square bore..

also.. I personally DETEST square bore to spread bore adapter plates... dont use one.. its just asking for vacuum problems.

but if I had one final word of advice.. make sure you match it to your engine.. since your getting a new engine.. get a new intake and carb kit.. our old stock manifolds arent very impressive.. get a new holley or edelbrock set.. slapping a new carb on a crappy intake (especially since your old engine was a truck motor if I remember right)..

the biggest thing you need to consider is heads and cam.. the bottom end is all the same.. matching your heads to your intake to your carb to your cam is the best way to get better power and mileage..

|UPDATED|9/15/2004 9:56:34 PM (AZT)|/UPDATED|

whats up man?(1980 vette-stock 350)I changed my carb this year and thought I would go with the "direct bolt on HOLLY",from MID-AMERICA,well put it on and low and behold,it was't that direct bolt on like they said;some mods needed! send it back and bought the Q-JET that comes stock with the car;direct bolt on;couple of adjustments on the screws and RUNS beautiful!!!!out of the box. Q-JET is the way to go!!

I bought my Holley- 4175 from Summit and it had everything it needed to bolt up. I did have to get an adaptor fitting to hook up the power brake vacuum line. The Holley thread size is smaller. Once everything was hooked up it ran OK but was very rich. I had to down size the discharge nozzle and play around with the cams. I ended up using the #21 discharge nozzle (it came with a #40). I still thought it was to much gas when I stepped on it so I changed the plastic cam to slow down the shot amount. According to the book that came with the carb that is the only changes you need to make it run good. I think it could use some different jets if you want to dyno tune it and get the best performance out of it.
It has been on there for 4 years and I have yet to have to mess with it. I got 17mpg on my last trip to NCM but thats with the OD trans I put in it. Around town (heavy right foot) I get about 13mpg's.

Here's my .02 worth.

I too was looking to change the carb set up on my '73. It had the Q-jet with stock manifold. I looked at several options and ended up with a Holley 670 Street Avenger. Nice thing about this carb is that it has all the vacuum ports needed for the Corvette to operate (lights, air controls, ect.) It has vacuum secondaries that you can change when they come in by just changing a spring on the top of the carb...very slick! Took it out of the box and bolted it onto an Aluminum Edlebrock Performer intake. The draw back is that the carb cost $425.00 new....but it was well worth it, worked great right of the box (adjusted the air/fuel mix screw and that's it).
The whole set-up was $550 but it was well worth it. The Holley is (to me) a lot easier to use and can be adjusted to fit any performance mods you do to the engine.
Look on Ebay and you can find some great deals...if you call Holley and Edelbrock, they'll tell you what part numbers to use for your car with any mods you have done.

Good Luck!

Guys

Some very interesting thoughts and curse you for remembering that my poor vette has a truck engine, will i ever live down the shame ???.

From what you are all saying it seems i should also buy a new intlet manifold as well, and i can live with that, i would just like to clarify a couple of points and they are:-

1/ i won't need to buy an upgraded pump
2/ it really is best to buy a matching manifold and carb
3/ Quadrajet is the way to go
4/ it will all fit on to my current (ahem)truck engine and later will fit on my nice new powerful Chevy V8 block/engine.

5/ a good bet would be to contact Edelbrok(for the sake of agrument) and get part numbers from them for the carb and manifold and not actually buy it from them.

A couple of other points to note i do not care about the gas mileage as long as i get performance and i cut my teeth on SU carburators so am not afraid of twiddling screws etc.

Oh and finally thank you all for your input past and future i knew i could rely on this list.

Also "pattern", 'chu' i don't know what you mean !!!




Gary

&^ Vette

JagVette said: Guys From what you are all saying it seems i should also buy a new intlet manifold as well, and i can live with that, i would just like to clarify a couple of points and they are:- 1/ i won't need to buy an upgraded pump 2/ it really is best to buy a matching manifold and carb 3/ Quadrajet is the way to go 4/ it will all fit on to my current (ahem)truck engine and later will fit on my nice new powerful Chevy V8 block/engine. 5/ a good bet would be to contact Edelbrok(for the sake of agrument) and get part numbers from them for the carb and manifold and not actually buy it from them.

well the summary of the points here is dont think is very clear..

you mention a nice new powerful engine.... have you found it yet ?? honestly until you are sure what engine you are buying... DONT buy a new carb.. you really need to match it to the cam and heads... are you keeping the heads ?? (if they are truck heads... i wouldnt)

here are my answers to your summary questions ..

1 depends on what carb you get. ok for q-jet, not ok for speeddemon..
2 yes without a doubt, and best to match cam/heads/intake/carb.
3 depends on the heads and cam too much to answer, and other factors like stick/auto, street, pro-street, street-strip use..
4 not necessarily... if you decide to use vortec heads the intake wont work. you must consider the impact of each of the other items in the system.
5 the manufacturers dont sell items to you.. they will refer distributors though..

in the situation you are in. with the truck motor...

you need to decide what you want in the end. in the previous thread aftershark mentioned the holley "cam and up" kits...

if you buy one of these (edelbrock makes them too) then youve solved your whole problem.

get your short block rebuilt or buy a new one.. the performance is in the cam, heads, intake, carb. you can slap these parts on ANY 350 and they run pretty close to the same...

changing piston makes a little difference, a hotter ignition makes a little difference, headers make a little difference. but changing heads & cam is like night and day.

if you want mileage and decent performance go spread bore/q-jet, if you want to lay 50 ft black marks behind your car... dont go q-jet.

decide what you want.. and then figure out what combination will work best to get that..

to be honest the difference in a 650 rochester, holley, demon or edelbrock with vac secondaries is actually rather trivial if anything at all from a performance standpoint.

if you tell us what you want to build then we can give you guidance on how to get there instead of personal preferences..

ie..

if you told me that you were building a 350/300, 350/400, or a 383/425 i would give three different answers and that without factoring transmission, rear end, and usage.