Read the how to articles 90 primary and secondary injectors orings question...

[Corvette95]

Thanks! Pete is going to port them for me next week.

Originally Posted by Paul Workman

To be clear, ONLY the 1990 PRIMARY injectors ALSO have a O-ring in the injector bore (in the Injector Housing). Whereas, the secondary injectors are sealed ONLY at the tip - pressed against the boss which is situated in the middle of the secondary runner.

For this reason, when max porting is done on the 90s ONLY, the O-ring boss at the tip of the injector (in the PRIMARY runner) can be removed* entirely as the O-ring at the tip of the PRIMARY injector is redundant. Instead, the O-ring surrounding the injector body at the top of the PRIMARY injector provides the necessary seal.

HOWEVER, IF the motor is to remain stock and not ported, then both the primary and secondary injectors will have O-rings at the tip, AND the primary injectors will also have a second O-ring at the top of the injector body (found in a groove cut into the injector bore about 5mm below the mouth of the bore (as Hans (ccmano) said.

*This is exclusive to the 1990 IHs only: An argument can be made that the air flow in the 90 LT5s can be slightly better in fully ported Injector Housings than later Zs, b/c the obstruction posed by the primary (only) boss can be removed entirely when performing maximum porting.

[Paul Workman]

Originally Posted by Corvette95

Thanks! Pete is going to port them for me next week.

Good! I'm telling ya after only doing the top end and Marc putting it on a dyno for a fine tune, it was like a totally different car! You're gonna like it!

I think you'll agree that this is how they should have come from the factory. In the gen-III LT5 they finally got the porting right: One massive oval as the two runners are Siamesed (more like morphed) into one...tells me Pete n Marc and now others were spot-on way before the gen-III came out in 95 (intended for the 95-96 model year that never was installed in a production car).

This "one-off" copy of the gen-III was featured at a C4 gathering in Bowling Green 3-4 years ago. And, if I'm not mistaken, it now resides in a ZR-1 owned by none other than Graham Behan - former engineer at Lotus & currently engineering at Lingenfelter.

[Corvette95]

Yeah, I have seen that model, nice, based on appearance only, and I mean only, the factory version looks better. I am very happy to have Pete doing my porting. I may have to look to another powder coater, my friend and registry member in Washington hasn't returned my calls or texts, he may be in virus lockdown. I finally have the entire car apart from front to rear, I am going to paint the exterior while the engine is being done. I just need to pull the manifolds and exhaust and the re-install will begin!

[A26B]

Originally Posted by Paul Workman

Good! I'm telling ya after only doing the top end and Marc putting it on a dyno for a fine tune, it was like a totally different car! You're gonna like it!

I think you'll agree that this is how they should have come from the factory. In the gen-III LT5 they finally got the porting right: One massive oval as the two runners are Siamesed (more like morphed) into one...tells me Pete n Marc and now others were spot-on way before the gen-III came out in 95 (intended for the 95-96 model year that never was installed in a production car).

This "one-off" copy of the gen-III was featured at a C4 gathering in Bowling Green 3-4 years ago. And, if I'm not mistaken, it now resides in a ZR-1 owned by none other than Graham Behan - former engineer at Lotus & currently engineering at Lingenfelter.

The engine was installed in a ZR-1 owned by Ken Lingenfelter. Graham retired from Lingenfelter over a year ago. He now lives in Kentucky and offers his services personally.