This is Accessories extension for the LS3 Chevy Engine (https://www.thingiverse.com/thing:1911808).

My finished project : https://www.thingiverse.com/make:743429

Printed parts list (8)
4 x Connector_1 : Layer:0.15mm Raft:no Brim:no Support:yes Infill:100%
1 x Connector_2 : Layer:0.15mm Raft:no Brim:no Support:no Infill:100%
1 x Oil_Cap : Layer:0.15mm Raft:no Brim:no Support:no Infill:100%
1 x Oil_Cap_Gasket : Layer:0.15mm Raft:no Brim:no Support:no Infill:100%
1 x Oil_Filler : Layer:0.15mm Raft:no Brim:no Support:yes Infill:50%
1 x Oil_Filler_Cap : Layer:0.15mm Raft:no Brim:no Support:yes Infill:50%
1 x Oil_Filler_Cap : Layer:0.15mm Raft:no Brim:no Support:yes Infill:50%
1 x Oil_Filler_Gasket : Layer:0.15mm Raft:no Brim:no Support:yes Infill:100%
2 x Screw_1 : Layer:0.15mm Raft:no Brim:yes Support:yes Infill:100%
2 x Screw_1_Gasket : Layer:0.15mm Raft:no Brim:no Support:no Infill:100%
1 x Sensor_1 : Layer:0.15mm Raft:no Brim:yes Support:yes Infill:100% (2 colors ; bronze and black)
2 x Sensor_2 : Layer:0.15mm Raft:no Brim:no Support:yes Infill:100%
1 x Sensor_2 : Layer:0.15mm Raft:no Brim:yes Support:yes Infill:100%

Accessories (7)
4 x m2x5mm SHCS
2 x m3x10mm SHCS
1 x m3x5mm SHCS

Assembly
Look at pictures.

More add-ons

https://cults3d.com/fr/collections-de-designs/dancan13f/chevi-ls3-engine-add-ons