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'89 R3500 Crew Cab 2wd to 4wd conversion & beyond

Started out with 2wd TBI350 with SM465 to current 4wd with 454, 700r4, NP241
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To set up the timing, the crank reference angle is set at 60° in the terminator software. That value should be 10° over the max timing you will run but not more than 75°. The factory crank sensor isn't adjustable so I just made sure it lined up to be digital falling which means the sensor is looking for the trailing edge of the "tooth".

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Setting the cam sensor in the distributor is a big more complicated; it involves math. Cam sync location (degrees BTDC #1) = "Ignition Reference Angle" + “A” + (“A” / 2). The value for "A" in a V8 is 90°. So with the 60° reference angle, my math looks like this:
​
60° + 90° + 90°/2 = 195° BTDC on #1​

You also have +/- 30° of forgiveness if you don't hit it right on the mark. This all comes from the Holley install information.

I made my own timing tape. I also measured it out to verify the 195° from the TDC mark. The tape is also marked out for 0° to 90°. You've also gotta make sure it's on the compression stroke.

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Then I set the distributor cam sensor so it's at the trailing edge of the "tooth" for the digital falling signal.

20240213_151020.jpg

I am a little concerned the harness plug is too close to the fuel lines to allow for enough adjustment if it's needed once I can verify timing with a timing light. Problem is if I move it back a tooth, I'm afraid it will be into the firewall. At this point I figure I need to be prepared to make some changes once it's in the truck. I was also thinking I need to verify that flat spot in the distributor housing will got on the engine side like I have it, not the firewall side. I don't think it would work that way because the harness plug would be hitting the intake. @Capt Ron, do you remember how your distributor is orientated?
 
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nvrenuf said:
There's a used RJ intake assembly with throttle body on Ebay right now, no fuel rails included so it's like the auction has your name on. :deal:
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Hmm, the only one I saw on ebay was just the lower half for $1100. I'll have to search again.
 
mrk5 said:
I am a little concerned the harness plug is too close to the fuel lines to allow for enough adjustment if it's needed once I can verify timing with a timing light. Problem is if I move it back a tooth, I'm afraid it will be into the firewall. At this point I figure I need to be prepared to make some changes once it's in the truck.
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Did you put it at 195 before TDC on the compression stroke?

Also, moving the distributor does not change the timing with your setup, you would have to move the crank sensor, which you can't easily do, its fixed. (If you move the distributor way too far it would then suddenly fire the wrong cylinder though). This is why I mentioned if the timing light doesn't match the ECU then you would change it in the ECU software.

However, I would not change it unless you have verified TDC with a piston stop, as the error in the pointer could be why its off, it may not be the target, you don't know until you use a piston stop. This isn't required, though I do it on every engine build or cam swap just for accuracy.

Holley has a fixed timing setting so you can verify the computer matches the timing light.
 
mrk5 said:
I wonder, would that intake be a big difference in performance?
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I'm going to guess it would give you a little more top end, possibly mid range, but your current runners are a little longer for better bottom end. I don't think for your use its worth $1200, that's for sure.
 
folkenheath said:
Did you put it at 195 before TDC on the compression stroke?

Also, moving the distributor does not change the timing with your setup, you would have to move the crank sensor, which you can't easily do, its fixed. (If you move the distributor way too far it would then suddenly fire the wrong cylinder though). This is why I mentioned if the timing light doesn't match the ECU then you would change it in the ECU software.

However, I would not change it unless you have verified TDC with a piston stop, as the error in the pointer could be why its off, it may not be the target, you don't know until you use a piston stop. This isn't required, though I do it on every engine build or cam swap just for accuracy.

Holley has a fixed timing setting so you can verify the computer matches the timing light.
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Yes, I had set the crank there when I finished the valve spring install and I also put my finger over the spark plug hole to double check.
 
folkenheath said:
I'm going to guess it would give you a little more top end, possibly mid range, but your current runners are a little longer for better bottom end. I don't think for your use its worth $1200, that's for sure.
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I was thinking it wouldn't be huge power gain. More of a cool factor like @nvrenuf mentioned which would need to be a lot cheaper. Really makes me wonder if it will ever sell at that price. Can't believe there's a big demand for those.
 
Yeah if you had a bigger cam and wanted more HP up top it would definitely be better no question, I just don't think that's your application.

Edelbrock makes a similar style ("XT") manifold but it's for rectangular port only.
 
folkenheath said:
Did you put it at 195 before TDC on the compression stroke?

Also, moving the distributor does not change the timing with your setup, you would have to move the crank sensor, which you can't easily do, its fixed. (If you move the distributor way too far it would then suddenly fire the wrong cylinder though). This is why I mentioned if the timing light doesn't match the ECU then you would change it in the ECU software.

However, I would not change it unless you have verified TDC with a piston stop, as the error in the pointer could be why its off, it may not be the target, you don't know until you use a piston stop. This isn't required, though I do it on every engine build or cam swap just for accuracy.

Holley has a fixed timing setting so you can verify the computer matches the timing light.
Click to expand...
Say the timing doesn't match, would I be changing the reference angle number in the software to get it to match up?
 
mrk5 said:
Say the timing doesn't match, would I be changing the reference angle number in the software to get it to match up?
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Well first you need to make sure it's not varying with RPM, if it varies at all you can change the inductive delay to fix that.

Once that is solid and not moving with RPM I still would not change the reference angle unless you have verified TDC with a piston stop.

If you do verify with a piston stop (don't use one without removing those two rocker arms first to prevent potential damage), and it is a confirmed error on the timing accuracy, then you could change the reference angle, but I would use the "timing correction" feature to fix it instead.

Because the reference angle is supposed to be fixed at 60 degrees for your engine I would guess, and if you move that to say 58, then you may limit your max timing to 48, which it may want 50 or so at cruise w/ light load.

Last Gen 6 I did with a GM cranks sensor like yours the timing was dead on and rock solid.
 
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