video of first run before carb synch
After 5 years of running Weber 40 DCNFs very successfully on a Mondial 3.2 with a pretty good power pickup (290 hp, 240 ft-lb at flywheel) and increased reliability, we decided we coould freshen the heads. Well, one thing lead to another on the flow bench...
The car now has 44 DCNF carbs with 38mm venturis, ported head with larger intake
valves, higher lift cam, 10.5:1 pistons and tubistyle european s/s headers and a new s/s exhaust system of my own design after pouring through exhaust textbooks and speaking with experts on the subject.
To get a bit more technical, the 44mm Webers will be tuned on the dyno, but the going in jetting which doesn't seem to far off is 145/F24/190 with 52 idles. It was intentionally jetted a bit rich, and we'll back down. Spark is supplied by the system it has had for 4 years, a Mallory electronic distributor triggered by an MSD 6AL. The cam kept near stock durations to keep a strong bottom end and match the math involving the venturi, but increased lift to .360 from a stock of .348. The flow bench shows ann increased flow velocity with and peak flow up over 10%, with flows up at all lifts giving a much greater area under the flow/time curve. the target was much more for a reliable daily car with a strong bottom end rather than for a high end screamer, which is more appropriate for the 3500 pound 2+2 GT.
Other attendant details included a Pierburg fuel pump, ceramic coating the headers, upgrading all of the water hoses to silicone, high torque starter, and freshening the original 85 amp alternator to 100+ Amps.
Amazingly, even with the grossly unsynchronized carbs, it runs with a minimum of spitting, but should smooth out substantially as initial barrel flows were all over from 2 to 10. Although too early to tell, the flow through muffler system sounds as expected with a low smooth quiet tone, and you can still roll a golf ball end to end. While a bit louder than stock, it is quieter and better sounding than a previous tubi muffler.
We'll see how she sorts out and check some dyno numbers later. Hope this is entertaining for some.