1995 Silverado K1500 father/son build

[Erik the Awful]

I googled the grind and got the link below. It looks like a nice bump in performance over stock, but recommends 9.5:1 compression, so it'll be a 91 octane motor.
http://www.pbm-erson.com/Catalog/Erson/Camshafts/Hydraulic Roller-Late Model Step Nose_E/ERSE119700

 

[clgodwin79]

I googled the grind and got the link below. It looks like a nice bump in performance over stock, but recommends 9.5:1 compression, so it'll be a 91 octane motor.
http://www.pbm-erson.com/Catalog/Erson/Camshafts/Hydraulic Roller-Late Model Step Nose_E/ERSE119700

Wow! That’s awesome! Thanks for the help! My original plan was to run the stock fuel injection setup with the upgraded spider injectors vice the poppet style and probably a slightly larger fuel pump with an adjustable fuel pressure regulator under the hood.

I think that I’ll still be able to do this but I originally was thinking I’d get it running on the black box, then swap to a 411 PCM and pay someone, probably like Blackbear Performance, to help me tune it. But now I’m thinking that it’ll run like trash probably on the black box because it’ll constantly be trying to recalibrate or recalculate since it going to be a fairly rough and choppy idle based on the cam.

But also, I guess I need to research what the stock L31 Vortec compression is. Because all I did to the cylinder/combustion port was a slight surface decking on the block and heads and basically stock style domed pistons that are .030 over. So I’m not sure I’ll be at 9.5:1 compression with that setup.

My goal was to not carb swap it and keep the stock injection to keep the functionality of the OBD-II and be able to dial it in with tuning vice carb jet changes. Maybe my plans will have to change.

If I knew I was going to end up losing the factory injection I would have just built it as a stroker.

Ideas?

Thanks again guys! This is all awesome and amazing help!


1995 Z71 standard cab stepside
Swapping to 1996 Vortec OBD II

 

[clgodwin79]

Ok, I tried looking up L31 Vortec factory compression ratios and there seems to be a lot of varying data on it. Some claim only 8.5:1 and others as high as 9.5:1.

I did tell my machinist guy that I wanted to run 87 octane and also asked what size torque converter I needed to run and he said that factory stall would work with my cam.

So.....if the factory compression ratio is even close to 9.5:1 how is it that guys run 87 octane all of the time? I don’t get it. Maybe we’ll just run the 91 to be safe and see how it runs.

But I’m definitely more than willing to detune it to run on 87 octane if need be. All of this is based on what some people seem to keep forgetting. This is going to be daily driven by a 16yo kid who will likely drive it as stupidly as any of us would have at that age with that amount of power.


1995 Z71 standard cab stepside
Swapping to 1996 Vortec OBD II

 

[Erik the Awful]

Your stock Vortec induction system will run decent without a tune, but you'll want to get it tuned at some point. My motor was originally in my '99 Suburban, and it didn't choke when I floored it - my cam's 230° duration at .050", with .515" lift.

I didn't deck my block, didn't deck nor port my heads, I put flat-tops in it with no overbore, and I'm supposedly at 9.7:1 compression. There are calculators online - you need to check, because with decking and a dome you might be over 10:1.

 

[clgodwin79]

I’m thinking that the 8.5:1 is probably the TBI variant and that the Vortec L31 was closer to 9ish:1

But that’s just my guess. Maybe my build sheet will show how much was decked from my block and heads. But looking at the heads it definitely wasn’t much because there are areas where it’s not fresh new machined metal for sure.


1995 Z71 standard cab stepside
Swapping to 1996 Vortec OBD II

 

[clgodwin79]

Ok. I guess I need to do my homework and talk to my machinist and get a little more info. He built it to what I told him that I wanted but didn’t do a good job relaying that info to me. Or I just didn’t ask the right questions maybe.

Either way, like you said, I definitely need to figure it out.

Was the cam you put in yours a flat tappet or roller lifter style? I keep the roller setup even though it cost more. But my cam also isn’t nearly as radical as yours!


1995 Z71 standard cab stepside
Swapping to 1996 Vortec OBD II

 

[Erik the Awful]

Well, some places say the TBI heads are 76cc, and other places say 64cc. I have both a Vortec and TBI head sitting in the dirt behind the shop, and I got a whatchacallit for measuring volume for Christmas, so if I get time this afternoon I'll cc both of them.

I have a hydraulic roller cam.

 

[OutlawDrifter]

You can run 9.5:1 on 87, especially with fuel injection. I did it in my L98 Z28 Camaro for years, it definitely ran better on 91 however.

That cam has more duration than I would run in a 4x4. 212/218ish or less would be better, it does have a +4 ground in, so that will bring the power in sooner.

Cam spec's say a stall is recommended, and I'm sure it will need some gear even with a 33" tire.

The Ram Jet 350/Marine cam that was noted earlier in this thread is awesome for a stockish 350/383 cube engine, and wouldn't need a stall converter.

 

[clgodwin79]

I was planning on 3.73 gears. I don’t remember off of the top of my head what it currently is, but I want to say 3.43?!?! I’ll check the RPO code and see because I’m almost positive that they were never swapped. But I could always count the teeth of the ring and pinion as well. Just not until the frame has been cleaned up and painted.

What did you see on my cam spec sheet that says that a stall is recommended? I have no idea how to read that stuff.


1995 Z71 standard cab stepside
Swapping to 1996 Vortec OBD II

 

[clgodwin79]

Does this help?

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1995 Z71 standard cab stepside
Swapping to 1996 Vortec OBD II