Hi Ohio
I also have a suburban 95.
I slamed mine with a 6 inch drop.
Getting ready to put a torque arm in and rear disc brakes off my impala/caprice 9C1.
I built my own BMR style 10 bolt cradle and will be installing some time this week.
I am dropping an LT1 cam in mine as well.
I have a customers corvette to do a Timing chain oil pump and distributor rebuild on tomorrow.
So monday r so that will be out of the way.
I am pulling the L05 out of my suburban and doing a complete reseal, LT-1 cam, HMV55 oil pump, heavy porting the stock heads ( yes they will flow it just takes a bit of machining). The trick on those heads is to make the siamese ports as close as possible. Last set I did flowed nicely once the web is cut down to 0.100 and the swirl ramp properly radiused I will take some pictures and share a post on how to get them to flow.
I have a 4L60E in my suburban and I am putting a torque convertor out of a 4.3 V-8 to raise the stall from 1200 to 2100.
The other thing most people mess up with the stock LT-1 cam is they put way to much valve spring.
GM makes an orange colored beehive shaped valve spring that was never installed in any factory engine it was a part made for Hi reving Nascar engines back in the early 1990s. They are really cheap like 6 dollars each. The difference is they have a light weight seat pressure of 180LBS but they are not made of regular steel the material used on the ones I am speaking of have a much shorter stasis after pressure is removed and when they rebound. This allows a regular SBC valve like a 1.9 to open to .575 and handle 8500 before the float. The stock EST HEI or opti spark will run out of dwell time before you can get to that RPM. I use a CDI homebuilt triggered from the HEI reluctor or the optic spark cam signal.
So your first issue with tune.
The LT-1 cam does not require a different memcal it has a 117 degree lobe center and the TBI will function fine.
You do need to change your convertor to make use of the higher torque band.
The other issue with the swap is the roller cam does sometimes false the knock sensor causing timing to be off.
The headers will do this as well.
This is why a lot of people are putting their timing up 14-16 degrees.
2 ways to fix this
one is to use the EST module from a 1984-91 corvette with the knock sensor from the same.
The aluminum corvette heads also made more noise and the sensor is less sensitive.
The other way is to use a pre 1984 distributor with mechanical and vacuum advance but wire the Pickup to your existing module and wire the coil leads to the distributor cap mounted coil or get a MSD HEI remote coil adapter.
The computer will enriched the fuel when it fails to retard the timing enough to stop the false readings.
Either way with stock pistons and Combustion chambers you want to set your timing at 33 degrees at 3000 rpm after 30 seconds soak time.
This way your not breaking the top ring land under load or pulling up hill.
You should also do the mods to the TBI to make the best out of it.
The stock TBI can be made to function fine as a 670CFM set up.
Mods to the TBI are pretty simple
1. Make sure that the throttle plates and shaft are not worn if so either rebush or replace the lower unit.
2. Cut the ring and blend the upper side of the throttle plate.
3. Knock out the fuel pressure regulator seal and adjust your fuel pressure to 16 LBS (I run mine at 18 LBS this makes the block learns force lean all the time. The ECM will start super rich and lean out as far as it will go so while driving you always get plenty of punch when yo hit the peddle. I did install a 95 impala fuel pump so you may want to do the same.)
4. Install the 1/4 spacer beneath the injector head.
5. Pay the 40 dollars for the JEGS salad bowl air cleaner mod.
6. Tiewrap the injectors wires tightly to the top of the injector housing to clean up air flow around them.
7. Only on the LT-1 cam raise the TBI with either a manifold dual plane with adapter or Performer EFI or a throttle body spacer 1".
Do not make the 7.4 liter TBI swap mistake it will run crappy.
On my burb I have tri-Y headers and Zoomies so I do not have enough back pressure for the MAP to change when my EGR valve is opened then closed so it sets a CEL 32.
I am going a different route and making a circuit that provides the EGR test sequence the desired MAP change.
Another big mistake made by older guys is the old 160 thermostat and old Hypertech chips designed to use the 160 tune.
The fuel at the pump almost always is not gasoline today.
The motor fuel is now up to 10% alcohol so it is gasohol.
If you run your engine at 160 with gasohol you will have issues with soot in your oil.
The alcohol emulsifies water with fuel and with your oil and if the engine does not run at least 180F it will not burn off.
On our old trucks you get more of a rear wheel power gain by converting to electric fan than you will out of the 160 mods.
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