okay the 99 4.8 to 6.0 swap is complete with only one bad issue. I used the 4.8 flywheel on the 03 6.0 with the nv3500 behind it. I mounted the 6.0 starter and it doesnt line up with the flywheel. The starter is now to close to the flywheel and wont bolt in. The crank on the 4.8 did seem longer than the 6.0. Do i need a flywheel spacer of some sort, a new flywheel (if so what could i use and where can i find one) or to shim the starter ?

 

I see you have a '99, there was some discussion a while back about the differences in the cranks of both the 4.8L and 6.0L from earlier years. People usually only discuss the issue about the 6.0L. I'd be willing to bet that a newer 4.8L flywheel is going to be the solution.. get some clearance pics and compare to others, there's plenty of people around with pics to compare with

 

if a flywheel is what i need id like to at least go with a lighter flywheel...SPEC makes a nice one but i can only find it designated for the LS1. i would hate to get the wrong flywheel. Times an issue for me. Race season is ending and snow is about to fall here in 2 months!

 

Read post 180 through 184. That might answer your question. If the crank is sticking out past the seal then you have the older/longer crank. I think it will still bolt up to a 4L80 but not a 4L60/65. (without the adapter) Looks like you need the adapter or a newer trans and converter to match your new 6L.

https://www.performancetrucks.net/fo...at+broken+part

 

well what if the transmission is a 5 speed manual nv3500 transmission like i have. im not an automatic guy!...so might there be the same issue with the xmsn that im running?...ive read and heard so much about the nv3500 being able to hook to the 6.0l regardless of the longer or shorter crank .

 

I dont know. It may have something to do with the manual transmission pilot bearing. It may give you the space you need.

Have you looked at the 4.8 starter? Are the the same size etc? I dont know if it would have the tq to turn over the 6L but at least you could identify if that is the problem and not the flywheel etc...

 

The starter that i have for the 6.0L is a 6.0L starter. The problem is definately because of the flywheel is closer to the block on the 6.0L. Im thinking i need a spacer between my crank and the flywheel to make the starter fit properly. The real question is definately where!...Where would i find a flywheel spacer from? And while im taking the flywheel off id like to change it to a lighter flywheel....where might i find one of those? All i can seem to find is one for an LS1. anyone know if it will work though its for a 6.0?

 

anyhow, problem solved!...the problem i was experiencing was that my previous 99 4.8 had the longer crank than the 6.0 i swapped it with. I had to put space between my flywheel and crank on my 6.0 to make things work..i just made some shims!

 

how did you make the shims? what material ?

 

I used a certain thickness peelable shim washer. We used them quite often on the Blackhawk Helicopters I work on. Im not sure what thickness I ended up with. Just kept peeling a layer of the shims at a time and refitting the flywheel til it fit perfectly.