Hello Everyone, my name is Mykk (pronounced Mike) I wanted to come by and share my motor swap.
This is my truck:
This is my daily driver and the only vehicle I own.
This is the motor in my Silverado:
And here is the back story:
I originally purchased this truck new from the dealer in early '04. It's a base model in work truck trim that came with a 4.3L v6 / 4L60E trans / 3.42 rear gears
The idea for this V8 swap started with the notion that I was simply taking the original 4.3L design and adding two cylinders. So why not a LSx/4.8/5.3/6.0 swap like the rest of the world? I don't think those engines are suited to be truck engines, that don't start building power until 3500rpm+ and they cost a ton to rebuild and even more with performance parts.
I decided to stick with the old fathfull and tested SBC, and thanks to 50 years of market saturation rebuild parts and performance parts are dime a dozon, easy to find, and I didn't need to sign off a loan to build it.
The block: 86-95 350ci, four bolt mains, roller cam block
bored .040" over
ZZ4 rotating assembly, 3.48" stroke, 5.7" rods, balanced
Vortec 906 cylinder heads, rebuilt, gasket matched
Speed Pro H345NCP-40 pistons sit .004" in the hole, with a .039" thick head gasket this makes 10.3-1 compression
LT4 hot cam, Summit quiet geardrive, Proform aluminum 1.6 ratio roller rockers, Comp 26918 beehive springs, hardened pushrods
.525"/.525" valve lift, 218/228 duration @ .050"
Vortec L31 fuel injection, upgraded fuel injection spider, CFM-tech oversized throttle body. Hooker long tube headers.
So there's the motor, now on to the swap.
4.3L come out:
Vortec 357ci going in:
Due to different era's of engine design, the 350ci crank won't bolt to the LSx type 4L60E using the factory torque converter, so instead I had a custom TC made for my swap with a flash stall between 2800-3200rpm
Stock: left, Custom: right
I used GMT800 V8 motor mounts & frame brackets, but used a LSx to SBC motor mount adapter plate.
After some re-pinning of fuel injector leads, adding two more wires for two new injectiors and using the original 4.3L accessories and brackets. I had a L31 style SBC in my 2004 GMT800 truck
I drove it this way for several months, and was disappointed with how it was running. After hours upon hours of data logging and tuning, reduced power output and drinking 8-10mpg. I decided to do something pretty radical in todays automotive world. I decided to ditch the fuel injection in favor of an old school carb.
And now that F.I. will no longer be dictating what kind of engine internals can be used. I also decided to bolt on a set of performance heads, bigger camshaft and used a thinner head gasket for more compression
Removed the LT4 hotcam in favor of a COMP XR276HR-10, with the 1.6 RR's
.535"/.544" valve lift, 224/230 duration @ .050", 110 lobe sep, 106 Int centerline
I also removed the geardrive for a roller timing chain
Patriot 'Vortec' heads, 2.02"/1.6" valves, 185cc Int runners. Transferred over the beehive springs and roller rockers.
Professional Products Crosswind intake manifold (now a single plane Hurrican Plus), Speed Demon VE 650cfm carb. Summit billet aluminum distributor with an aggressive timing curve dialed in. The thinner .028" thick head gasket bumped static compression up to 10.7:1
The truck still has the original computer in tact to control the automatic trans, gauges and creature comforts. It just has some extensive PCM tuning to function without the fuel injection.
Did I mention I run a Custom PCM Tuning business, www.CustomPCMtuning.com
This is my motor swap story. A pretty different build that gets alot of attention and sounds like no other Silverado on the road.
A short Vid:
http://www.youtube.com/watch?v=ITRcJFxZntg
I did a few other performance bolt on's tp the truck, for an intake set up I made a ram-air intake using the ducts in the bumper cover
I also installed a set of 4.10:1 rear gears with a powertrax no-slip locker
Cheers ~Mykk