Was going to keep two and block the rest, and run .028s per general recommendations over at racingfuelsystems.com.

Any reason not to go this way?

I’ve already made the air bleeds and PVCRs to get started and have plenty handy for adjustments.

.028 should be fine at 1and 3 position.

Getting closer to testing.

I wanted to see how this carb was setup so I measured everything before drilling. I bought some bits on Amazon to do the work so I wasn’t sure what I’d get with sizing so I measured every bit that I used - all measured as marked.

These carbs are from the post-bankruptcy, bastardization to clear out the remaining stock, era, so specs are a bit of a toss-up.

Stock specs from my post above were from old BG literature.

“Stock” Demon C-12320 metering block measurements:

Emulsion bleeds (1-5, top to bottom): .030, blocked, .030, blocked, .030, blocked. (spec is .031 for all except for position 5 which is supposed to be .038 - I posted .031 across the board but it’s supposed to be .038 for WOT hence the leaning out issue - not necessarily the case with mine but still not optimal).

Siphon break: .028

IFR: .037

PVCRs: .058

IABs: .070

HSAB: .028 (not stock - spec is .031)

Measurements were the same for both.

I modified the metering blocks for the smaller/fewer emulsion bleeds. The emulsion bleeds are now at positions 1 and 3 (2, 4, and 5 are blocked). This will put it back to more of a traditional double-pumper emulsion style. Emulsion bleeds are .028.

IFR was moved to the low position and taken down to .035.

PVCRs were drilled out and replaced with a .067 jets.

I wanted to take the IABs down to .025, but the Demons use a specific jet type that I needed to order. I got a bunch of blanks, cheap, from Allstate Carburetor, but I’ll give the .028s a try to see if I can get a decent idle and transition. If it’s too lean, then I’ll move down.

All in all a pretty cool experience. I did manage to break a tap in one of the PVCR passages (mother f’er!!) and I thought I’d have to replace a metering block. I was able to pound it through and cleared it from the main well. I won’t be able to run a PVCR jet in that one so I moved it to secondary duty.

Tomorrow I’ll throw some keys in them (80s primary, 90s secondary) and see what I get on the trailer. I don’t think I can get out to test this weekend, but I’ll be able to at least get them running.

And I figured out why the port engine was going lean getting on plane and cruise - my fault - the power valve worked its way loose. It was finger tight and causing just enough of an air leak to create an issue. Whoops. :picard1:

That will cause a rich condition . Raw gas going into the manifold.

Thanks. You’re right - and I knew that. Wishful thinking to find the problem.