HTMSteve

Thanks for the help so far everyone, will be trying ideas this weekend and will report back progress. I did hold one carb up to a light source last night and could see light around half of one butterfly on the secondary set but the other one was more centered. Will try to loosen screws and adjust to better center.

Still looking for best practices to add O2 bungs. Was hoping someone already had made or makes sandwich plates or has a good method for how and where to add bungs and keep everything dry and with no leaks.

Young Performance

Do you have the big, cast aluminum elbows with a SS tailpipe? If so, you won't be able to add a bung to the elbow. It will either need to go into the SS tailpipe or in an adapter, like you mentioned, between the manifold and the elbow. As long as you have the room to clear the boat and the hatch, you can put it in the SS tailpipe. As for the adapter, you will either have to make it or have it made as no one makes it. I've made them before for a Volvo engine that I needed to tune. There are available for Mercury exhaust, but that's all I have seen that is commercially available. They really aren't that hard to make. You may want to call IMCO. They may have made them in the past or could make one.
Eddie

Baja Rooster

iTrader: (1)

I've got a brand new plate for bbc manifolds with the wet joint if that's what you have.

HTMSteve

Here's what I have...I would guess dry joints since the hoses go around the joints.

mike tkach

iTrader: (3)

with that setup the o2 bungs need to be put in the tailpipe.

HTMSteve

Thanks for all the help so far everyone, I've learned a LOT! I bought a small drill set yesterday and decided to blueprint the carbs as they are today. I'm glad I did, because in doing so, I noticed that rear carb had ALL the T-slot feed restrictors removed, and the holes left behind are about Ø0.110". The carb that was in front has ALL 4 TSFRs in place and are Ø0.085" each, see picture below.

OK, here's what I have:
IFR = .040 and located at top of metering block all 8
IAB = .071 all 8
MAB = .037 all 8
PPV = 6.5 (now manifold referenced, completed these today)
SPV = 8 or 8.5 they have E 8 5 0 reading CCW, but have plugs to block these.
PVCR = .081 all 8
PJet = 89
SJet = 94
Emulsion holes = .090 3/side 6/metering block all same on all 4 blocks
Thanks Steve

fbc25el

I moved my IFR to the lower position and it helped my idle greatly.

HTMSteve

What did it help with your idle?

Did you leave the tops open or plug them? Are you running a roots too? My main issues are surge and engine dies when put in gear. Did you have either of these issues and did moving the IFRs help either or both?
Thanks,
Steve

MILD THUNDER

iTrader: (3)

You would want to leave the top hole open after moving them to the bottom. Your idle quality should improve and have much less, if any blower surge. Blower surge is simply from an unstable supply of fuel which is seems to be more of an amplified problem, with the pulsations in airflow in the intake manifold at idle. Normally, the engine stalls due to being lean while putting a load on it. When its surging, its lean/rich lean/rich lean/rich each time the rpm swings up and down.

The purpose of doing this mod, is what I explained earlier in regards to stabilizing the fuel flow from the idle circuit.

SB

iTrader: (1)

Here's a good link for the IFR mod:

http://racingfuelsystems.myfunforum.....php?f=25&t=18

Jmarkaudio (Mark Whittner) is a pretty serious carb tuner. Won a few times at the recent carb shoot outs at BLP (Bo Laws Performance)]