wheelin247
1/2 ton status
i have a basically stock 350 but its got a racing cam and drag headers what cfm should i get 650 or 750 need help soon as possible thanks ....
CK5
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650 cfm or 750?
- Thread starter wheelin247
- Start date
angelglo
1/2 ton status
do this. mulitiply your cubic inches x the maximum RPM's you will be using. divide that number by 3456. then mulitply that number by your VE%.. that is the volumetric efficiency percentage. this is the amount of air that your motor will be breating in. race engines go to 100%. 1/4 mile cars go way above 100%. with intake, headers and cam, try using about 95%. after all is done, you will get the MINIMUM cfm's you should use. i hope this helps.
SuperUnknown
1/2 ton status
I would go with the smaller one.
750 is probably too big for you enging.
750 is probably too big for you enging.
650. 750 is way to big for a mild small block. max rpm will depict cfm requirment.
your right. I don't understand the jeep thing!
your right. I don't understand the jeep thing!
nyyef
1/2 ton status
even though the stock carb is about 750 or 780cfm (something like that), a 650 will give you better driveability and throttle response which would be much better for a truck.
Knife.
knife.coloradok5.com
Knife.
knife.coloradok5.com
You've got to figure in the primary side for driveability and economy...a Q-jet has small primaries..right around 250 CFM for the 750CFM model. Just read an interesting article by David Vizard, and they actually got better performance with 1000CFM carb, (I think it was a SBC) and before everyone goes saying that is way too much, I agreed too. But the guy knows what he is talking about, and the article explained it. The URl is now dead, but looks lik eit may come back, if someone wants to read it in the future... http://www.dorianyeager.com/index2.html
