so, been chasing this part throttle lean deal, got most of it tuned out, but i picked up a pair of 625 cfm comp afb's, and i couildn't resist trying them......
i rebuilt both of them, they look great, still have the plating on the linkage, and the bodies are still pretty shiny. i broke them down, one had alot of water in it at some point, and it needed the most detail work. i have a small ultra sonic cleaner at work, man, that thing really does a number on cleaning things, you should have seen the water after i was done.....
so, with both torn completely down, i reassembled them with .101 primary jets, and .071 x .047 rods. the secondaries are .104's. quite a bit smaller than what i was running in the 750's, i had .118's in the rear, and .113's with the same rods in the primaries.....
after hooking them up, setting up my linkage, it was time to fire them up. i couldn't get one primed, but it finally went.(electric fuel pump to prime them..) it fired right up, it was cold, so i had to goose it here and there, and all of the sudden, up to 3800 rpm's, and stuck! it took me about two seconds to realize what the hell was going on, and then i hit the key.
note to self:
always remove scoop linkage when it the scoop is not attached,
IT MIGHT GET CAUGHT UP AND HOLD BOTH CARBS OPEN.
well, after that little freak out, linkage gone, i fired her back up. purrs like a kitten, dead rock steady idle at 650 rpm's in gear, good ratio, 12.6 at idle.
time to drive.
part throttle is great, mid to high 13-s, the engines sweet spot. acceleration is great, mid 13's, and heavy acceleration is still compromised, just like the 750's, because of lack of boost referencing. i have a guy in town my blower guy knows, i guess he figured something out, so i will have more detail on that issue later.....
i got into her full throttle for a stretch of 3 to 4 seconds, looked ok at 13.0 even, would like it a little richer, might try jetting up the secondaries to .107's and see what we get. not quite sure if it pulls as hard, but seat of the pants is deceiving at a 60 mph start in this car, much easier to tell when i am down low, 20 mph or so. i am sure the 750's probably make more power, but i really want to see what the mileage difference is between the two.
so, overall, i am very happy with the driveability of the 625's, and i can't help but think mileage will be different, and overall city driving more enjoyable.
stay tuned for mileage results, and my vacuum advance setup, and (hopefully) boost referenced afb's...........
stay cool peeps,
davey
