Hi Jim,
I certainly agree with Brent's statement about having more more power with a single 4 barrel.
The only time IR induction has more outright power is when the induction system is optimised for high mid to top end.
Your setup with 42mm chokes certainly sounds like it is "up there" for a little 289.
Sizing for Weber jetting is 0.5mm increments, so your next main would be 1.55mm. My curiosity is the the 2.00mm air corrector.
Where is it rich or lean at the moment?
One camshaft I chose for one of my cars, had in the description "violent midrange for pulling out of corners", and rpm range of 2800-6700 plus.
This is a street registered car, good manners (for me anyhow).
This cam had more power everywhere than the cam I had, which is a popular camshaft, 288, 252 @ .50 LSA 108 .345, my new cam was 276, 242 @ .050, LSA 106, .350 cam lift.
I ran both cams with my 44 IDFs, they both had more peak torque in the middle at 4800 rpm, but less peak power, peaks of 6400, compared to a 750 annular Holley peaking at 6700, about 15 horsepower.
The Webers were great on a twisting track, gymkhana etc, but the single 4 was faster on a long track.
The "violent cam" came on really smooth, and pulled away well from other traffic.
Wide LSA, all else being equal, has less overlap, but has a later inlet closing point, which then has lower compression on a test gauge.
This gives less low speed torque. The closing point is the most important timing event.
Overlap helps scavenge the cylinder of exhaust gases by using the exhaust gas momentum to help pull in, and fill the cylinder with fresh A/F mix.
Once the inlet charge is flowing in, it helps blow out the remainder.
All in a perfect world. As overlap is increased, the amount of exhaust gas trapped in the cylinder at low rpm is increased, which gives the camshaft rough idle characteristic.
Of everything I have learnt, one thing thing stands out. Never change more than one thing at a time.
When I changed the above camshaft, everything else stayed the same.
A tiny valve seat change, but same carb etc.
I built a tiny 1.5 litre 4 banger, 250 @ .050, 107, and 2 x 48 DCOE Webers.
That engine was streetable at 2500 rpm, torque peaked at 6200, hp peaked at 8500 rpm.
You can see these carbs are really big for the engine.
So it comes down to what you really want.
By the sounds of your youtube videos, I bet it feels really nice to drive.
I still would have tried the intake and carbs on the engine while you had the 106 in there, even just for testing giggles.
Gary
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