Guest Posted January 26, 2004 Share Posted January 26, 2004 I have a basicly stock 18000mi 2bbl motor in my 71J, with the exception of a Pertronix elec ignition (1181), an Accel coil (8140) and soon to add electric fan.My question is how much would I increase my MPG if I go with a four barrel intake/carb set up. I'm not after big horsepower gains because I could use this truck to climb a tree if needed with the 4:09 gears, just better than 10mpg on the highway.Block casting: KTO025Heads: B1233472Listed torque/horsepower: 350/230Listed compression but not checked: 9.0:1 Link to comment Share on other sites More sharing options...
Smartin Posted January 26, 2004 Share Posted January 26, 2004 A well tuned motor with a 4bbl QUADRAJET on it will get excellent gas mileage. If you keep your foot off the floor.The trick is keeping your foot out of the cavernous secondary valves, and also making sure your motor is running in top condition. A factory 2bbl will actually get worse gas mileage than a factory 4bbl qjet. Link to comment Share on other sites More sharing options...
Guest Posted January 26, 2004 Share Posted January 26, 2004 Would this require a head change or would mine do alright?What would be the cost of such a change and how difficult are parts to obtain?Wayne Link to comment Share on other sites More sharing options...
Smartin Posted January 26, 2004 Share Posted January 26, 2004 No need to change the heads on you motor!Probably the easiest way to find a 4bbl intake is to call www.taperformance.com and buy one of their Aluminum 350 intakes. Find a 350 quadrajet and rebuild it or have it rebuilt.You can probably get a used 350 qjet on www.v8buick.com in the parts wanted forum. I have a qjet for a 455 sitting here, but it works better on 455s. The factory cfm for the 350 qjet is 750cfm. The 455 qjet is rated at 800cfm. Link to comment Share on other sites More sharing options...
Guest Posted January 27, 2004 Share Posted January 27, 2004 Hi Wayne! Another full size Jeeper here! Small world! <G> If you want to boost your fuel economy, getting the GM TBI kit custom efi to put on your intake and it will get you closer to 16 mpg. You can buy junkyard parts and buy just the harness or wire it yourself if you are EE inclined. Getting an overdrive if you highway drive a lot will help too. I assume Dana 20 transfercase? You may be able to get an adapter to go with that to a 700R4, but I am switching out to a NP208 (from a Chev, which is same side front drop as your Jeep) A BOP pattern TH200R4 can be also be used, but it's not all that strong (A & B trans in Langley, BC, Canada had a guy that used to beef them up with TH350 internals years ago when I worked there) Synthetic oils in your diffs help too, but the closed knuckle axle on the front doesn't help much unless you have unlocking hubs on the front. Link to comment Share on other sites More sharing options...
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