Thread: which carb to use

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hello, I am building a 283 sbc and would like to know which carb cfm is better 500cfm or 600? been told that the 600 would be too big for that size of engine due to the heads. Motor will be bored, more for cleanning walls, rv cam, basically it. Just something to cruise around in and get decent gas mileage, Oh yea a 4bl carb and intake to add to list. Any advice. thanks

My 283 std bore has a 600 edlb and seems to be fine. 280 cam. 305 trk heads.

A good dual plane intake and no more than 600cfm on the carb and you stillmight have to jet it back some to keep it from running too rich.

I too had a 600 CFM carb on a pretty much stock 283. I wouldn't say it was over carb'd. A 500 CFM would work fine too though. I agree with others that you want a dual plane manifold and probably wouldn't want to go any bigger than 600 for a 283 cruiser.

Thanks for the reply, I was told also if I went with the 305 heads that a 600cfm carb would work as to bigger chambers? I am using plan stock 283 heads do you think it would make a differnce?

Reason on carb choice is had a guy wanting to sell me a 600 reasonable, and know the guy, but even at good price if carb is too big, it's too big. Why spend $$ on something that won't work for me? thanks

I had 1.94 humps on mine and can't see any difference. but I also steped up from points to accel electric and 1969 model "full" solid cam to a hyd 280 cam. And added headers.

Theres a formula that will calculate from cubic inches and rpm to tell you what you need.I seen it at holley,the seem to know what their doing

I'd think the original 283 heads would work much better then the 305's. The 305 heads just don't flow well. Even the stock 283 power pack heads with the right cam would make for a very clean and crisp good revving 283. The 500 carb should work great with your setup....

Originally Posted by Dave Severson

I'd think the original 283 heads would work much better then the 305's. The 305 heads just don't flow well. Even the stock 283 power pack heads with the right cam would make for a very clean and crisp good revving 283. The 500 carb should work great with your setup....

One other area that is often over looked is the fact that 305 heads are very prone to cracks.

i think a 600 cfm carb would flow fine, i've got a 71 302 in one of my 60 galaxie convertables, complete stock engine, never been rebuilt has about 70,000 original miles on it and my carb went ou so i thru a 2bbl to 4bbl adapter plate on it and an eddy 600 and it runs beautiful, not rich not lean, and it launches hard when the secondaries kick in

also look @ primary throttle bore, the smaller the bore the quicker the throttle response due to increased volocity of fuel/air mixture through the bore. 31 5w

Originally Posted by erik erikson

One other area that is often over looked is the fact that 305 heads are very prone to cracks.

but if you use the hi-po 305 heads you will have a nice torque motor.