I am considering a throttle body type fuel injection for the wagon . I can't seem to tune the Q-jet to get more than 10 mpg and with the ram air hood not to be too lean at a steady freeway cruise. Both the Holley and Accel systems look to also control timing while the FAST ,MSD, OR Projection kits are fuel control only. Any help would be great . Thanks , Tom

 

Don't think I'd be in any kind of hurry spending that kind of money on a Projection system, as likely not gonna do much for a 5,000 lb car with a 455 under the hood. I'd trace other problems 1st, such as distributor advance issues. Most older dizzy's have gummed up advance shafts, and should be disassembled and lubed up by now. Also, maybe contact Q-Jet guru Lars Grimsrud V8fastcars@msn.com. Real good guy, and really knows his tuning. Recall travelling in my fathers new 73' Pontiac 455 Grand Prix, when a kid, and were only getting about 13 mpg cross country touring. Gotta keep costs in mind, as the cost for a Projetcion system, can buy lot's of gas.

 

Talk to Cutlassefi on here about the Accel system. A TBI system off a 454 BBC would work too. You just need an adaptor for the intake and a CCC Olds 307 distributor. Mine runs fine but sucks for gas mileage. I need a proper exhaust set up, cobbled together. I sure it is leaking triggering a false lean reading and pouring the fuel to it. Although I pulled similar highway mileage to what most tbi 350 sbc 4x4's were getting. I plan on buying a big bore tbi and installing it on my Cutlass.

 

Depending on your engine, rear end, etc, you would probably do better on gas milage by putting the money into an overdrive trans.

 

Gotta agree with gary here as put a 700R4 od tranny on my car with 3.73 axle. Worlds of difference on the highway, as like cruising with a 2.56 axle. Haven't checked the highway milage, but gotta be lots better than a stock TH350 with 1.00 top gear. Sure makes long highway trips, more enjoyable though.

 

Thanks for the replies so far guys. The engine in the car is a fresh .030 455 with Edelbrock heads and intake with around 9.6 compression ratio and a mild camshaft . Also the distributor is a HEI vacuum advance unit with a reasonable timing curve with a total mechanical of 36 degrees by 2400 RPM. The trans. is a 700R4 with a lock up converter and the rear end is a 12 bolt Chevy with 3.73 gears . I have re-jetted this thing many times with no luck. I'm not sure how much "ram air"pressure the carb. gets at highway speeds with the hood sealed to the air cleaner or if the metering spring should be stronger . EFI just seems to be a easier way to control fuel for drivability and possibly fuel economy. ( I tried to PM Cutlassefi a few days ago , he may be on a Christmas break) The car is currently in the body shop , so no big hurry....

 

OK, already got a OD trans and a tuned ignition. If you're doing the swap for gas milage only, you're going to have to put on a lot of miles to make up the cost of the efi. Make sure your Qjet isn't leaking, gamaged, badly modified, etc before going with efi.
It's a heavy car with a 455, not optimal for gas milage. The relatively good gas milage of moden motors is a combination of engine/head design, cam, sequential port injection, and ignition all working together. Dont expect a big jump in milage by simply adding a tbi.