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School me on MR1 differences

Thread starter veedubtek
Start date Jul 18, 2018

Blazin14

Jet Boat Junkie

Jan 16, 2024

29-410 non HO
29-411 HO

How can you physically tell the difference. two ways:

1) The valve cover vent pipe is in a different location; HOs are toward the timing chain (rear) and non HO are in the forward slot (see the open slot, opposite the black block-off). The screwdriver is pointing to where the HO vent pipe should go.
2) Non-HO Inlet water to the block has 1 curved pipe. HOs are both straight. (No he, she or they or them)

These pictures are non-HO.

update: a Non-HO can not be swapped with a HO without some modifications and vise versa...