Looking to get more out of my 1988 C1500

[AChadwick]

I started my build about 3 months ago. I pulled a sbc 350 from a 1998 K1500 that has cast iron vortec heads about 5 years ago and finally got around to putting it in my truck.

My truck as the title says is a '88 c1500 with a small block 350 stock. I pulled out most unnecessary things to have a clean and spacious engine bay to make working on it easier. I installed the vortec 350 with a CCS40 Cam

• Exhaust Advertised Duration (Deg): 280 Degree
• Exhaust Duration At 0.050 Inch Lift (Deg): 214 Degree
• Intake Advertised Duration (Deg): 271 Degree
• Intake Duration At 0.050 Inch Lift (Deg): 207 Degree
• Intake Valve Lift (in): 0.410 Inch
• Lifter Type: Hydraulic Roller
• Exhaust Valve Lift (in): 0.427 Inch

I eventually ran out of money for the fueling system so I had bought a Chevy Performance TBI to Vortec intake manifold. Most people have said to put a carb in it but I needed the project done by a certain deadline.
I'm utilizing the TBI and the truck is running great besides some minor hiccups I had to get it to where it is. I was talking to a buddy about modifying the TBI module and did some reading online for the "free" mods to the TBI module itself.
My question is has anyone had any significant luck with radiusing the flanges and or boring out the TBI. I'm looking for some other ways to make more power without breaking the bank and one thing that I have plenty of is power tools and sand paper. I've also seen people notch their intake manifold and it helps with vacuum and has a relatively good increase in midrange power.
I have heard that with great boring comes great reprogramming of the computer / replacing said ECM and attaching fuel pressure regs to the fuel line not to mention getting a decade newer fuel pump.

All these things are fine and can be done but before doing any of this I was wondering if anyone else has done this and has charts of the before and after modifications. Just to see if it's even worth the time and effort.


Yes I want more power but I don't want a whine or whistle coming from my engine bay. I'm trying to keep it non forced induction.

 

[Ranger550]

I started my build about 3 months ago. I pulled a sbc 350 from a 1998 K1500 that has cast iron vortec heads about 5 years ago and finally got around to putting it in my truck.

My truck as the title says is a '88 c1500 with a small block 350 stock. I pulled out most unnecessary things to have a clean and spacious engine bay to make working on it easier. I installed the vortec 350 with a CCS40 Cam

• Exhaust Advertised Duration (Deg): 280 Degree
• Exhaust Duration At 0.050 Inch Lift (Deg): 214 Degree
• Intake Advertised Duration (Deg): 271 Degree
• Intake Duration At 0.050 Inch Lift (Deg): 207 Degree
• Intake Valve Lift (in): 0.410 Inch
• Lifter Type: Hydraulic Roller
• Exhaust Valve Lift (in): 0.427 Inch

I eventually ran out of money for the fueling system so I had bought a Chevy Performance TBI to Vortec intake manifold. Most people have said to put a carb in it but I needed the project done by a certain deadline.
I'm utilizing the TBI and the truck is running great besides some minor hiccups I had to get it to where it is. I was talking to a buddy about modifying the TBI module and did some reading online for the "free" mods to the TBI module itself.
My question is has anyone had any significant luck with radiusing the flanges and or boring out the TBI. I'm looking for some other ways to make more power without breaking the bank and one thing that I have plenty of is power tools and sand paper. I've also seen people notch their intake manifold and it helps with vacuum and has a relatively good increase in midrange power.
I have heard that with great boring comes great reprogramming of the computer / replacing said ECM and attaching fuel pressure regs to the fuel line not to mention getting a decade newer fuel pump.

All these things are fine and can be done but before doing any of this I was wondering if anyone else has done this and has charts of the before and after modifications. Just to see if it's even worth the time and effort.


Yes I want more power but I don't want a whine or whistle coming from my engine bay. I'm trying to keep it non forced induction.

One of the nice things about fuel-injected engines with ECM, is they adjust for altitude, thus not running rich, without re-jetting a carburetor, from sea level to high mountain roads and highways. I've rebuilt so many carburetors in my life, I never want to see one again. The last one I did was a chain-saw carb, but that's not the same as a car, since the jetting is done on the outside of the carb with screws.

 

[pressureangle]

I started my build about 3 months ago. I pulled a sbc 350 from a 1998 K1500 that has cast iron vortec heads about 5 years ago and finally got around to putting it in my truck.

My truck as the title says is a '88 c1500 with a small block 350 stock. I pulled out most unnecessary things to have a clean and spacious engine bay to make working on it easier. I installed the vortec 350 with a CCS40 Cam

• Exhaust Advertised Duration (Deg): 280 Degree
• Exhaust Duration At 0.050 Inch Lift (Deg): 214 Degree
• Intake Advertised Duration (Deg): 271 Degree
• Intake Duration At 0.050 Inch Lift (Deg): 207 Degree
• Intake Valve Lift (in): 0.410 Inch
• Lifter Type: Hydraulic Roller
• Exhaust Valve Lift (in): 0.427 Inch

I eventually ran out of money for the fueling system so I had bought a Chevy Performance TBI to Vortec intake manifold. Most people have said to put a carb in it but I needed the project done by a certain deadline.
I'm utilizing the TBI and the truck is running great besides some minor hiccups I had to get it to where it is. I was talking to a buddy about modifying the TBI module and did some reading online for the "free" mods to the TBI module itself.
My question is has anyone had any significant luck with radiusing the flanges and or boring out the TBI. I'm looking for some other ways to make more power without breaking the bank and one thing that I have plenty of is power tools and sand paper. I've also seen people notch their intake manifold and it helps with vacuum and has a relatively good increase in midrange power.
I have heard that with great boring comes great reprogramming of the computer / replacing said ECM and attaching fuel pressure regs to the fuel line not to mention getting a decade newer fuel pump.

All these things are fine and can be done but before doing any of this I was wondering if anyone else has done this and has charts of the before and after modifications. Just to see if it's even worth the time and effort.


Yes I want more power but I don't want a whine or whistle coming from my engine bay. I'm trying to keep it non forced induction.

I built a 400sbc with Dart heads, roller cam a little more than yours, etc. I spent for the bored/radiused/hotrod throttle body, and maybe it makes more power above 4500rpm but I go there so rarely that I really don't think I ever see much difference, and the throttle sensitivity is harsh; not a good tradeoff for me.

 

[Schurkey]

My suspicion is that the first page of the "Ultimate TBI Mods" posted on this web site is a TOTAL waste of time, if not actually counter-productive. Don't get me started on Scotch-Briting the protective plating off of the TBI unit, which looks really pretty and shiny (for awhile) but promotes corrosion of the base metal in the long term.

 

[Erik the Awful]

I'm looking for some other ways to make more power without breaking the bank

Spend money on a cam. You can take the time to port the heads and intake yourself, but that stock cam is a dog. Call your favorite cam company and tell them what you're looking for. If you have the ability to tweak your ECM it opens even more possibilities.

 

[AChadwick]

Spend money on a cam. You can take the time to port the heads and intake yourself, but that stock cam is a dog. Call your favorite cam company and tell them what you're looking for. If you have the ability to tweak your ECM it opens even more possibilities.

I understand that the cam isn't the best one but it is a hell of a lot more aggressive than the stock flat tappet that was in the engine originally and it allowed me to pick up some more horses without needing to open up the ECM. Those reasons alone is why I had bought it. I'm not currently looking to spend lots of money especially since my family has just gotten back from a road trip across the country.

Right now I'm looking to get that little extra 2-10% more power with spending little ($75) to no money.

Thank you for the feedback I truly do appreciate it.

 

[AChadwick]

My suspicion is that the first page of the "Ultimate TBI Mods" posted on this web site is a TOTAL waste of time, if not actually counter-productive. Don't get me started on Scotch-Briting the protective plating off of the TBI unit, which looks really pretty and shiny (for awhile) but promotes corrosion of the base metal in the long term.

Do you think that I could coat the TBI with a protectant to prevent corrosion? I'm not really trying to get it looking like a mirror but just opening the air ways a little more so the horses can breathe.

 

[AChadwick]

I built a 400sbc with Dart heads, roller cam a little more than yours, etc. I spent for the bored/radiused/hotrod throttle body, and maybe it makes more power above 4500rpm but I go there so rarely that I really don't think I ever see much difference, and the throttle sensitivity is harsh; not a good tradeoff for me.

By the throttle sensitivity being hard do you mean by it revving up too quick in park / neutral or in gear? I don't usually go above 4500 rpm but I do occasionally race my buddy who is building his truck. I don't expect the thing to turn into a power monster but more or less having it keep up with other vehicles.

 

[Schurkey]

Do you think that I could coat the TBI with a protectant to prevent corrosion? I'm not really trying to get it looking like a mirror but just opening the air ways a little more so the horses can breathe.

I don't usually go above 4500 rpm

Airflow through the throttle body is not holding back your power. You've already got more airflow than you need. You're looking for "improvement" in the wrong place.

I'd be looking at the exhaust system LONG before I dicked with the intake. What exhaust system is on the truck now? If you've got an ancient pellet-style catalyst, upgrading to a high-flow monolithic/honeycomb cat would be my first priority, along with replacing whatever else in the exhaust was in poor condition. "Shorty" headers didn't do much for my '88 K1500, other folks have better results. How old is your O2 sensor?

How are you getting EGR to that intake manifold? You WILL need to tune the computer if you've removed the EGR system.

How are you dealing with the coolant bypass that the Vortec heads (and maybe the block) aren't set up for?

10% power increase for $75 is NOT going to happen unless you've got the plug wires routed to the wrong plugs, or you need a new fuel filter 'cause yours is half-plugged.

2% power increase won't be noticeable unless it fixes a driveability issue you're having.

 

[pressureangle]

By the throttle sensitivity being hard do you mean by it revving up too quick in park / neutral or in gear? I don't usually go above 4500 rpm but I do occasionally race my buddy who is building his truck. I don't expect the thing to turn into a power monster but more or less having it keep up with other vehicles.

The larger (454 size) throttle body opens more area per pedal travel, so your light-throttle stop-sign pullaways take a more attentive foot. You get the same air at 1/8 throttle as you might on the smaller TB at 1/4 throttle. I cosign everything Shurkey says above.