[fbrown]

I'm at about the same stage you are with my conversion, using almost the same parts, LS3 crate etc. My car however is a 68 Lemans that is being converted to a GTO.

I ordered my wiring harness and computers from Speartech since for one reason or other I didn't like the other aftermarket solutions. The GMPP harness requires special software to tune and is not compatible with OBD2 scanners. It also does not talk to an auto transmission controller. The cost of this solution with a GMPP transmission controller is about nearly $2000.

Mast Motor Sports makes a harness/computer that looks very good on the surface but is not truly OBD2 compatible, supports only VDO CAN gauge and cannot be scanned by an OBD2 scanner. By the time you add the transmission controller you are at nearly $3000.

Speartech make a harness and uses GM computers for both the engine and transmission for $1695. This was the choice I made since it can use any of the standard OBD2 scanners, gauges or tuning software. The Speartech solution will also give you cruse control it you want it, which the other two do not. (Mast tells me the cruse has not been done on their computer and is not a high priority).

The main point of interest here is that your selection of a 4L60E will depend on what controller you use. Speartech tells me that for a 4L60E to work with the LS3 and factory GM controllers (NOT GMPP) that the transmission will have to be configured like it is being installed in a 06 Trailblazer SS and not like the typical Camaro transmission that is commonly used. Apparently the output shaft and control electronics are different.

I also had sticker shock when pricing starters. I have not purchased mine yet.

[b-man]

Originally Posted by fbrown

I'm at about the same stage you are with my conversion, using almost the same parts, LS3 crate etc. My car however is a 68 Lemans that is being converted to a GTO.

I ordered my wiring harness and computers from Speartech since for one reason or other I didn't like the other aftermarket solutions. The GMPP harness requires special software to tune and is not compatible with OBD2 scanners. It also does not talk to an auto transmission controller. The cost of this solution with a GMPP transmission controller is about nearly $2000.

Mast Motor Sports makes a harness/computer that looks very good on the surface but is not truly OBD2 compatible, supports only VDO CAN gauge and cannot be scanned by an OBD2 scanner. By the time you add the transmission controller you are at nearly $3000.

Speartech make a harness and uses GM computers for both the engine and transmission for $1695. This was the choice I made since it can use any of the standard OBD2 scanners, gauges or tuning software. The Speartech solution will also give you cruse control it you want it, which the other two do not. (Mast tells me the cruse has not been done on their computer and is not a high priority).

The main point of interest here is that your selection of a 4L60E will depend on what controller you use. Speartech tells me that for a 4L60E to work with the LS3 and factory GM controllers (NOT GMPP) that the transmission will have to be configured like it is being installed in a 06 Trailblazer SS and not like the typical Camaro transmission that is commonly used. Apparently the output shaft and control electronics are different.

I also had sticker shock when pricing starters. I have not purchased mine yet.

Thank you for the detailed transmission and wiring harness compatibility info, this is a huge help to me. Now I know how much I'll have to spend on a harness, figured it would be at least $1500. Best of luck on your project.

Originally Posted by gto65lvr

bman

I just wanted to thank you again for all this wonderful info and for keeping our economy alive. IF you think about all the goodies you are buying and the amount of people involved to get them to you I think you just about kept the US open for biz LOL.

You prob. saved over 100 peoples jobs.

I'm more than happy to share whatever info I've been able to 'mine' off of the 'net, and help others figure out what direction they need to go when doing an A-body LSX swap. It's hard to figure out what to do when searching through different threads that have bits and pieces of somewhat vague information. Hopefully I can make this thread a good archive of information as well as interesting reading, with as much great help as I've been receiving from the membership it should be a success.

For as long as I've been involved in this hobby (almost 35 years) I have helped to support a lot of small aftermarket parts companies, and buying new parts from GM can't hurt either.

There's lot of good stuff for our cars made here in the USA, Canada and by our Aussie friends as well.