Cam, stall, gear ratio question

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Erik the Awful

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I think your O2 sensor is too far back. I put mine a little too close in my header collector. Otherwise, I don't see anything glaringly wrong with your combination.
 

PlayingWithTBI

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I think your O2 sensor is too far back. I put mine a little too close in my header collector.
I don't know if your EFI has the capability, or table, where you can adjust the delay to compensate for the position of your O2 sensor. Usually if it's off you'll get stumbling because the ECM is adjusting to soon or late based on O2 feedback. Here's the table in the EBL. It's based on Gms/Sec.
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Edit: for some reason I can't delete the 2nd snap shot, it's the same as the 1st.
 
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Thank you all for the tips on the O2 sensor and the rich smell, I will will be trying those out.

But honestly, I now wish I made a separate post about that. I am not so interested in the that issue as I am opinions on my cam, stall and rear gear ratio combination. Would you guys say that the specs of the cam are a decent match for the specs of the torque converter and rear gear ratio based upon my stated purposes? Keep in mind, my purposes are a balance of as much power and acceleration as possible WITH street drivability (while not being concerned with highway cruising and mpg). Is it too much stall for the cam or is it a good match up? I understand that there will be compromises to achieve these two conflicting goals but I am ok with that. This truck is not a track car or a daily driver. It is a fun machine for the street.
 
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arrg

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I have the same converter in my truck w/3.42 gears and a smaller (212/218) cam. With your combo, I can't see why you'd want less stall speed. I agree with LC2NLS6 though, your shift points should be somewhere near 6000 rpm for that combo.
 

Schurkey

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My main concern is the cam, stall, ring and pinon ratio combination
GM 350 Crate Engine Long Block #12568758
"VIN K" stock replacement engine. Functionally the same as the original engine. Dished pistons, too deep "in the hole". Low compression. Crying out for thin head gaskets.

FTI Lock-Up Torque Converter (ESR3082): 9.5in./2800-3000RPM
I don't know this company or their products.

Cheap, mass-market "performance" torque converters are a disaster. A "good" performance converter is expensive; and drives like a stock converter at low- and part-throttle. If this converter slips a lot in normal driving, it's not one of the "good" ones.

Richmond 4.56 Gears
4.56 seems excessively deep; but that'll depend on your tire diameter.

MSD Street Fire Ignition Box
Good luck. MSD quality has taken a nose-dive; and their Street Fire line was always imported from Asia.

I wouldn't walk across the street for Street Fire products if they were giving them away for free. But you already have it, so until it dies there's no reason to change (assuming it has a reliable rev-limiter.)

AFR 180 Fully Assembled Cylinder Heads (0918) 65cc Combustion Chamber... ... (I am guessing the final compression ratio is approx. 9.1 and I always use 93 octane. I have never noticed any knocking or pinging.)
WHY are you using premium fuel in a nothing-to-one compression engine? This is crazy. You might actually get more power from lower octane. Won't be much of a difference, but it's possible. And less expensive.

What thickness are the head gaskets? Anything beyond .020 is too thick. .040-thick gaskets are common.

Comp XFI268 Hydraulic Roller Cam DURATION: 218int./224exh. LIFT: .570int/.565exh (w/1.6) LSA: 113
Nice, mild specs yet still far "bigger" than the original cam.

Might not have been my first choice, but it should work OK.
1. Was the cam degreed?
2. Is the distributor gear compatible with this cam?
3. Does this cam/lifters use the OEM thrust plate and dogbones?

COMP 1.6 High-Energy Die Cast Aluminum Roller Rocker Arms
Die-cast arms? Kinda scary.

But then, I'm so old that I remember when aluminum rocker arms had a 2,000-mile service life. When it's me, I buy steel roller rockers from Comp.

High-Flow Cat
New catalyst, and the exhaust still smells "rich"?

There's something wrong. Maybe several things. One wonders if the new catalyst has quit working. ("Murdered by misfire".)

Flex-Lite Dual Electric Fan Kit/Edelbrock Aluminum Water Pump/New Radiator/Underdrive Pully Kit
That's some serious downgrading of the cooling system.

Front: Original OEM 16x7 General Grabber UHP 255/65R16
Rear: Original OEM 16x7 General Grabber UHP 255/65R16
Axle ratio is too deep. You've got a mild engine with low compression ratio. It's not set up for high-rpm power, but you've got small-ish tires, deep gears, and higher stall speed. You're throwing away any low-rpm power, and not fully using midrange power. But, sure, it'll make the engine seem peppy.

(there is a strong smell of gas when the engine is running that I haven't been able to pinpoint. The air fuel ratio and timing is perfect,
1. Define "perfect" A/F, and "perfect" timing.
2. How are you measuring A/F ratio?
3. "Smelling fuel" in the exhaust? Often a sign of misfire. Can be rich misfire, can be lean misfire, can be misfire for ANY reason except a non-firing injector. Fix the misfire, the eye-watering "rich" smell goes away and the catalyst is much happier.

perhaps it's the charcoal canister delete?).
WHY would you do that???

If the "gas" smell isn't from the exhaust, this is a strong possibility.
 
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CrustyJunker

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Sounds like you have a pretty good combo as it is. All those parts will work well together (my opinion). A 4-door Tahoe is a reasonable size/weight that you've already compensated with gears and converter. 180cc heads are a great size for that cubic inch/cam size and keeping your torque up. Vacuum brakes probably still behave - also nice!

Even a smaller converter would've been fine for that combo...But you're right in the power range you need to be. I don't think there's anything really worth changing at this time.

Me thinks swapping cams, gears, converters, or head gaskets to bump up compression would give you marginal gains you'd only measure on a dyno (and be a lot of work).

You've covered all the weak points and cost-effective upgrades. Anything more - you'll want a whole new combo and a 4L80.

Happy truckin'! :driver:
 
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