Quote Originally Posted by Greg Amy View Post
Give me the Cliff's Notes version...I'm busy drinking beer.

It's always been my contention that extra-US-market engine are compliant as basis for IT/ST builds as long as the components used are exactly the same as the US-spec car. This goes back to the early 2000s when someone (honestly, not me or "a friend") wanted to use a JDM SR20DE as a basis to build an ITA engine. In my opinion, it was legal to use a JDM SR20DE to build an ITA engine, as long as everything that ended up in the final assembly was the same - dimensionally and metallurgically - as the US SR20DE.

Same applies to STL. If someone wants to run, for example, a B16A (versus a US-spec B16A2) in STL in their Civic, I say it's compliant as long as the compression ratio is below 11:1 and the total valve lift is within .425" (dunno if it is). I know the B16A has different pistons and cams, but the compression ratio is within 11:1. And pistons and rods (and cams) are free (within prep limits.)

Now, if someone installs a JDM B16A engine with some wild-ass intake manifold and throttle body that was never installed in the US and tosses that into the car? Not compliant. Parts are decisively not what was installed in a US-spec car.

Otherwise, in the end, it really is the same thing, except for what the Shinto eunich ex-Ninja monk stamps on the block as it passed by on the production line. Compliant to the alternate parts letter, and compliant to the alternate parts spirit.

- GA
And there you have the rub, because:

e. It is permitted to use the OEM intake and throttle body from either the chassis or the installed engine.
1. Regardless of the intake chosen, the total number of throttle bodies must remain the same as the installed engine.

and:

2. All cars shall use the installed engine’s stock air throttling device (e.g., throttle body, carburetor) and intake manifold, unless noted otherwise.

If you install the JDM motor then you have to install the JDM ITB manifold, which as you point out isn't allowed as the JDM is a non-USDM item.