Hello. I have a Holley 4150 (list 3043, 386315006) on a Chevy 327 engine which runs very well. One of the bolt holes in the main body had gone bad, and I swapped the main body with a body of a 4160 (list 3005, 1743). I used also the primary metering block of the 4160 (with both primary jets and power valve of the old 4150 installed), and all other parts remaining from the original 4150. Started up; getting too much fuel through the discharge nozzles and the booster venturis. You can see the fuel literally flow into the engine, and the engine will stop after about 20 seconds cause of over fueling. Can only keep it running by increasing the idle speed.

I checked:
1. The float level: it is ok, as there is no fuel coming out of the sight plug of the primary fuel bowl.
2. Needle and seats: are ok, new.
3. The fuel pressure: its 5 psi which is also fine.
4. The floats: tested, they are not leaking (they shouldn't as it was running fine with the bad main body).
5. The power valve and its gasket: no leaks.
6. The accelerator pump diaphragm: no leaks.
7. The idle air bleed jets: open.
8. Gaskets: ok and not covering any holes inside the main body/metering block.
9. The choke valve: working correctly.

No improvement. I did check out the forum's archive, but nothing which I already didn't try. Any ideas?

Best regards, Joep