I looked it up and it shows its a 76 unit for a 454 Chevy,but it has a front feed bowl? Did Chevy ever use a front feed style carb? Any ideas what size it may be and what kind of calibration it came with? Any opinions on a starting tune up? Its going onto the following combo: IN DENVER COLORADO!!!!!!!!!! 364" engine 10.25 compression ratio 227-234@050 -.600" lift hyd roller Heads flow 290 cfm through manifold Dual plane ported intake 3500 stall 3.73 gear 3400 pd car street / strip usage Thanks
Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi This is from Cliff Ruggles site, http://cliffshighperformance.com/simplemachinesforum/index.php?topic=1378.0 Below is the difference between a 750 and 800 CFM Q-jet.
Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi That's where I saw it was for a Chevy BB But I also read where Cliff R said all frt feed mid 70s carbs were 800 cfm ,yet this one looks to be a 750 Also I thought only BOP car used frt feed fuel bowls???
Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi Did you look for the "bump" at 8:00 like in the left picture? That's the tip off of an 800 which you will think a 454 should get. Then again, 70 jets sounds more like a 750 carb. 800's usually get mid 70 jetting. I also thought Buick and Olds used the front feed. I guess there is an exception to everything.
Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi Mid 70's Chevy 454 carbs were front inlet, but still smaller cfm and divorced choke. ALL of the front inlet hot air choke models, Buick, Old's or Pontiac will be the larger castings. Most of the side inlet Chevy auto carbs from 75-up are also the larger castings, but they made quite a few smaller ones until 1980. The carb in question here is a big block carb, large MAB, and emission calibrated. This is an advantage for the high altitude application. It also has APT in the baseplate, if you can get the screw removed, an external APT screw can be added for fine control of the part throttle A/F without taking the carb apart. The carb will need a jet and rod change for what you are doing, and minor modifications to the idle system, but its a good choice for the application, providing you can use the factory divorced choke set-up.....Cliff
Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi I looked on the website but they arent shown? Do you stock these screws? Any other required modificaion needed to run external screw? Thanks
Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi The original apt screw has to be removed from the base plate, which can be a tough job. The new adjustable Apt screw then goes in the same threads. I don't do this on all my builds, but I do have the supplies on hand. The quadrajet I run on my car has this adjustable apt in base plate.
Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi Well there you have it ! Thanks sir!!!
Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi Those type APT screws can be difficult to remove. Some come right out, others will require heat, plenty of penetrating oil and patience. We install the external APT on most of the carbs that we do, the only ones that don't get it are the very few that we can't get out of the baseplate. Its a great feature, and makes for easy fine tuning on the engine without taking anything apart. There are a lot of items that we sell that are not listed on the website......Cliff