CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
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I'm running an Edelbrock Performer intake, and it's spreadbore. I've always wondered this, but never really thought to ask, what exactly is the benefit of once over the other? Or is one kinds better suited for a certain application?
Personally in my opinion a spread bore would be better for a daily driver that has fuel economy in mind. because you can cruise on the small primarys but when you nail it you have the huge seconadarys to get ya moving in a hurry.
yup,those Q-jets sound good when you open them secondaries up..Small primarys for cruising/daily driving.The secondaries can be adjusted to open quicker very tuneable carb.
Squarebore is more of a performance orientated system, like said above it tends to have better fuel distribution which is nice to have if your tuning to get them last few milliseconds off your ET's!
Their is absolutely nothing wrong with using spreadbore carbs for street cars, heck a properly set up Q-Jet can support alot of power!
Personaly, I've always prefered the squarebore for better part throttle performance on the street. With a spreadbore, as soon as you tromp the peddel everyone knows what your up to (wwwooooaaaah).
Personaly, I've always prefered the squarebore for better part throttle performance on the street. With a spreadbore, as soon as you tromp the peddel everyone knows what your up to (wwwooooaaaah).
Haha, true enough. By the time you see that cop hes already heard them big secondary's open!
Spreadbores do have that neat sound when they open up, but it all depends on the direction you are going with the engine/car. I don't care about economy so I have a squarebore, but if I was building a cruiser, I would of wanted a spreadbore.
So take into consideration what you want to do with the car and how you drive it, and decide from there. Worse comes to worse, you can buy an adapter plate for your intake to go from either style carb to the other.
Good Luck!
__________________ Mike
I drive nothing with less than 350 cubic inches....except my Celica Best of a 13.50 @ 107 Its like myspace BUT for gear heads
I have a 73 Nova, but I plan to put a Edelbrock Performer RPM intake in it and get a new carb maybe. I plan to take it racing, but I was wondering because I am going to drive it too. So, should I go with the squarebore or spreadbore? And I want to have a nice idle so peopel know what's up lol...I'm wondering would I still get that nice souding idle with a squardbore? And I was reading that the spreadbore gives better gas economy, is it a noticable over the squardbore?
Spreadbore for sure. It`s matched to the manifold and no need for an adapter that you have to use with the squarebore. The adapter causes a small performance drop in my experience and according to the dyno tests I have seen(old Super Chevy articles). I`ve used both on a variety of sbc`s with 350+ hp in Vetts, 1/2 ton pick up and El Caminos. I always got better milage and performance with the spreadbore.
Thank you, Jim. I do that also I was reading that you get the most torque when you use a an aftermarket cam. Is that true? If so, what kind should I get? I have a 350 and I plan on getting a new exhaust and headers too. Also, what size carb should I get? I know that I want a 4bbl carb through.
the camaro
yup,those Q-jets sound good when you open them secondaries up..Small primarys for cruising/daily driving.The secondaries can be adjusted to open quicker very tuneable carb. 
