[77TA]

I would like to discuss some things around fuel mixture settings with quadrajets and mechanical fuel pumps problems and soulutions and syptoms of problems. I had a 400 last year that with the stock AC pump the little short one. It would totally die out at the top of each gear. I changed to a new larger can AC pump and with my 455 it does not die or cut out now. I also changed to richer primary jets at the same time as the pump. I have 75 jets and 45 Rods, my secondary rods are .041 tips I think. I can see a little blck smoke when I rev it in nuetral punching the pedal. I don't know about on the road but probably the same. It runs pretty good but seems a litle flat after the initial punch on the pedal. It runs smooth but just does not seem to be moving the speedo needle like I think It should. I am thinking I'm a Rich on the carb primarys and may be looseing fuel pressure on sustained heavy throttle but not enough to cause cutting out if this is possiable. I am concidering puting my 72 jets back in and driving it. MPG is about 10mpg car is 77TA with 4 speed and 3.42 gear. timming is approx 34 total in at 2500-2800 Rpm some light pinging under light load 2000-2500 rpm none on heavy throttle. 9.6 compression 230/236 @.050 cam .490 lift.

[77TA]

I would like to discuss some things around fuel mixture settings with quadrajets and mechanical fuel pumps problems and soulutions and syptoms of problems. I had a 400 last year that with the stock AC pump the little short one. It would totally die out at the top of each gear. I changed to a new larger can AC pump and with my 455 it does not die or cut out now. I also changed to richer primary jets at the same time as the pump. I have 75 jets and 45 Rods, my secondary rods are .041 tips I think. I can see a little blck smoke when I rev it in nuetral punching the pedal. I don't know about on the road but probably the same. It runs pretty good but seems a litle flat after the initial punch on the pedal. It runs smooth but just does not seem to be moving the speedo needle like I think It should. I am thinking I'm a Rich on the carb primarys and may be looseing fuel pressure on sustained heavy throttle but not enough to cause cutting out if this is possiable. I am concidering puting my 72 jets back in and driving it. MPG is about 10mpg car is 77TA with 4 speed and 3.42 gear. timming is approx 34 total in at 2500-2800 Rpm some light pinging under light load 2000-2500 rpm none on heavy throttle. 9.6 compression 230/236 @.050 cam .490 lift.

[Tim Corcoran]

It could be that your secondaries are coming in too fast. Have you tried adjusting the spring that controls the speed that the secondaries open? Your mileage should be a lot better that 10 MPG.

Tim Corcoran

[mike nixon]

i agree with tim. you're probably rich on the primarys. if the secondary spring is set to weak it will cause both problems.
my 72 g/p with a 455 .060 over, raiv cam, 2 1/2 duals,th400, with 3:55 rear end pulled 16 mpg with a/c on the highway. mike