Its Time To Build Some BOOST!
Thanks, Aaron.
If this doesn't do the job, we may try a different carb (600?) as 750 does sound a bit on the largish size, but the one on my supercharged 360 seems pretty happy and it only makes a bit over 500 hp at the flywheel...
I'll keep you posted!:coffee2:
Well, we went for a ride today and were amazed to find A/F ratios in the 16-18:1 range at full throttle, from 3,500-5,500 rpm but it made 8 pounds of boost like that !!!
That's a sure-fire recipe for detonation, so we went back to the shop and removed the carb, after checking the float levels. (They were right on...)
Tomorrow (Sat.), I will take the blow-thru carb off my 360 Magnum-powered '72 Valiant and install it on the /6 car, as an experiment.
That carb is also a 750 DP (but, from
the Carb Shop) and is a $900.00 unit that was never quite rich enough to get rid of a stumble at part-throttle tip-in, at cruise. Also, it was not happy stall starting, going lean at about 2,000 rpm and stumbling pretty badly, bit unless you actively worked the accelerator pump.
Overall driveability was poor, but it made 445 RWHP with that original Carb Shop jetting on a chassis dyno.
I tried to fix the mixture issues, to no avail.
In an effort to
fatten it up...
I raised the float levels.
I installed more aggressive accelerator pump (plastic) actuating ramps
I went richer on all main jets by about 5 sizes
Changed out the accelerator pump squiters to bigger ones
I installed significantly smaller (richer) hi-speed air bleeds
I tried some warmer plugs
Nothing I did got rid of that stumble.
Nothing.
But, it IS pig-rich, now, and should wake up the boost on that slant six motor.
I never had the F.A.S.T. O-2 sensor on the V8, with that carb, nor did I ever have a timing light on it; so, I have NO IDEA where the timing is, but it runs good (lucky guess!) and is relatively fast.... low 11's in a 3,300-pound car (without driver.)
I won't take chances like that with the /6 car. I watch that A/F ratio like a hawk while Fredddie drives.
I'll have a report on this debacle for you, Sat. night.
Wish me luck...
All this is with 18 crankshaft-degrees (locked plate) ignition timing.
Oh well, like I told Freddie; if it were easy, everyone would do it!!! :blob: