Early to late LT5 parts compatibility

[pantera1683]

I am building a 402 for my 1994 using a 1990 block and complete 1990 heads sans cams. I would like to use as many parts from the 1994 as possible to complete the build. What parts from the 94 engine will not work on the 90 engine?

Thanks

[Jagdpanzer]

Here are are few items that come to mind:

Timing chain cover
Oil pan
Oil pan baffle
Oil pump suction tube & pickup
Oil pump

There could be more.

[A26B]

1. There is a difference between early and late cam sprockets, 1 flat early vs 2 flats late.

2. Along those lines, I would remove the center stud on the exhaust side of the cyl head & plug the hole.

3. The 94 injector housings will bolt on OK, but the 90 cyl heads have a 3/4" hole in the vent ports, where the 91-95 models have only about a 1/4" hole. You will need to install destructor plugs in the corresponding ports of the inj housings with a similar size hole. There is a good thread about this and I wrote a tech article for the HOTB newsletter. It may appear in the next issue.

4. Then there is the EGR system. If you can plug the 94 plenum & lose the rest of it.

[pantera1683]

Okay

1. There is a difference between early and late cam sprockets, 1 flat early vs 2 flats late. Can I use my 94 cams in the 90 heads?

2. Along those lines, I would remove the center stud on the exhaust side of the cyl head & plug the hole. Plug it with what?

3. The 94 injector housings will bolt on OK, but the 90 cyl heads have a 3/4" hole in the vent ports, where the 91-95 models have only about a 1/4" hole. You will need to install destructor plugs in the corresponding ports of the inj housings with a similar size hole. There is a good thread about this and I wrote a tech article for the HOTB newsletter. It may appear in the next issue. Yeah, I was following that thread, just need to find those Dorman 550-011 plugs

4. Then there is the EGR system. If you can plug the 94 plenum & lose the rest of it.

[A26B]

1. There is a difference between early and late cam sprockets, 1 flat early vs 2 flats late.
Can I use my 94 cams in the 90 heads? Yes, with the same sprockets.

2. Along those lines, I would remove the center stud on the exhaust side of the cyl head & plug the hole. Plug it with what? 3/8"-16 x 1/2" long set screw, with Loctite 565 or equivilant sealant. Screw in until flush.

3. The 94 injector housings will bolt on OK, but the 90 cyl heads have a 3/4" hole in the vent ports, where the 91-95 models have only about a 1/4" hole. You will need to install destructor plugs in the corresponding ports of the inj housings with a similar size hole. There is a good thread about this and I wrote a tech article for the HOTB newsletter. It may appear in the next issue. Yeah, I was following that thread, just need to find those Dorman 550-011 plugs.

4. Then there is the EGR system. If you can plug the 94 plenum & lose the rest of it.