Wideband
 

I'm getting ready to get a wideband cause I don't feel certain that my carb set up is right using old school methods. I have the engine installed and I don't have a way to dyno it. Plus I have another carburetor so I want to set up both and see what I get. I have a Weber that came on the 350 Mag that I cannibalized for accessories and intake. I believe that is 600 cfm or maybe 625. I have rods, springs, and jets and I'm close on spark plug color. But I also have a Rochester in my basement that I was doing for a 79 350 Camaro...and the guy that owns it disappeared.
So since the Weber is just barely enough carb to spin 5200 according to some calculators I have seen, I think I'll run the Quadrajet for a try. I won't have to do a marine carb for the fuel telltale cause i am running an electric pump. Any worries with venting and etc?

The engine is a 9.8:1 forged piston 383 with Dart small runner iron heads and a roller valve train with a Comp Cams OE style CS 268XFI HR13 Cam
Valve Lift .570” I, 565” E. Duration at .050, 218 I, 224 E, 113 lsa, 109 icl. It has a nice quench height of .040".
It's very snappy, rips right up to wide open and then just stops accelerating. I think it's due to the small head ports. But maybe it's just as much as I'm going to get from a small block pushing a heavier-for-it's-length hull. I want to get what it can give so that's why I will put on the bigger carburetor.

I feel like I ought to go the last couple of tuning steps and get the AFR right.
Who has used the Innovate AFR kits? Are they good? Can I extend the wiring to my helm area for live use testing? I was thinking I would use one for setup and then remove it to my tool box so I don't have to think about powering the sensor heater and about wetting the sensor. I don't think that my cam is reverting anything, I have tall long risers that are dry way back. But no sense ruining stuff.

What other widebands are there for reasonable money. Any?

I am using, and have continuously used the Innovate MTX-L wide band for the last 6 years. Works great.

You would need to buy the extension kit to get the gauge to reach the helm/dash. That's what I did. The AFR gauge took the place of my fuel gauge.

I would run it full time because beyond the tuning and performance aspect it is also a tremendous troubleshooting tool to identify fuel or spark issues. I run a very similar motor with a bigger cam and have no reversion issues. I've got over 200 hours run time on the system. I feel naked without it.

What he said. ^^^

The wideband is very enlightening. You think that things are close but there's just no way to get spot on. I put a wideband on a tuned carb and picked up another 5mph with some jetting changes.

Love it guys! So since I have less cam I can probably expect to keep the sensor dry. I'm going to set it up permanently.

Just some more feedback regarding running and tuning. On the water running at cruise you will not be able to tell the difference performance-wise between 12.8 AFR and 13.2 other than the gauge saying so. So I don't sweat getting the AFR dialed in at say 12.8 rock solid from cold start to WOT.

In general I target the following ranges:

Cold start, no load, idle: 12.5 - 12.8
Warm idle, no load: 13.5- 14.2
Warm idle in gear: 13.5
Throttling up to get on plane (typically 17-30% TPS): 11.8-12.5
3000 rpm cruise 12.8-13.2
3000 to WOT 12.8 progressing to 12.2-12.5 at WOT

This has worked for my application and I am N/A. So take this merely as one data point.

If your AFR is grossly outside those ranges you will likely start to see performance issues. For instance if I richen the idle to 10.5 it sounds like a top fuel motor and the IAC goes bat **** trying to tame the idle. If I'm 14.7-15.2 at idle it gets very crisp but not very stable during shifts.

Also for reference my cam is a Crower hyd roller 221/230 @ .050", .525/.545 on a 1.5 rocker, 114 LSA on a 110 ICL in a 377" stroker (standard bore).