IAC options?

**dyeager535** · 10-01-2013

So taking my sweet time, getting around to mocking up the throttle body on my Olds FI intake. It's a BBC throttle body, I'm planning to build the motor up enough to get some use out of it's larger bores. Running into fuel rail clearance issues, on both sides actually. Think I can work around the throttle cable issue, but if I could get a smaller IAC, or an adapter that moved it vertical, it would allow some options in intake to TB adapter thickness. The LS-series IAC's look the same as the TBI ones. Anyone familiar with an IAC that is shorter but compatible? Will be running a 1227727 if it matters. I'm not even sure a 90* adapter would solve the issue. May have to live with the 2" spacer, but that creates problems of it's own. Due to intake design, not going to allow me to offset the throttle body to gain clearance either.

**EagleMark** · 10-01-2013

The BBC IAC already saves some room... there's also a TPS with plug that points up...

**JeepsAndGuns** · 10-01-2013

I ran into the same problem when I went to MPFI. A tbi throttle body without the injector pod was too wide and would hit my fuel rails. After much looking and playinging around with different ones, I ended up using a slightly modded vortec throttle body.

**dyeager535** · 10-01-2013

You have any pictures of that? Like this? http://www.ebay.com/itm/Vortec-96-20...ht_1004wt_1399

I want to keep the stock air cleaner, so the BBC TB obviously helps in that goal, but adapting the air cleaner to a different TB might be easier than trying to force the BBC TB to fit. Apparently that won't work though, I'll have to measure, but the intake I'm working with is cast very goofy, there isn't much metal to work with, the 454 bores are almost too large to fit. Hard to tell from this image, but its kind of like a cylinder in an engine block...too much boring and you end up hitting "air". http://www.gmcmhphotos.com/photos/40...ion/p3687.html It's the nearest intake, you can just barely see the passages cast in it. Unlike the TBI intakes of later years, the passages for vacuum are cast into the mounting flange of the intake, vs being all in the TB.

So far it appears TPS is no issue, it's just the IAC and throttle cable stud. If using the BBC TB, think I can just re-do the throttle cable stud so it's inboard of the plate it mounts to.

**JeepsAndGuns** · 10-02-2013

Looks to be the exact same TB that I used. I had to cut off that little arm and trim it a little. Also, the V8 ones are already 75mm, they just taper in under the throttle blade. I had a local machine shop remove the taper from mine.

You can see some pics in this thread: http://www.gearhead-efi.com/Fuel-Inj...Getting-closer

**dyeager535** · 10-03-2013

1001132155.jpg 1001132156.jpg

Sorry for the picture quality, terrible phone is all I have to take pics with.

I suspect if I am even able to fit the 75MM throttle body, I'd end up shifting the problem from needing a thick one-off TB adapter/spacer, to having an even more odd TB adapter/spacer AND having to re-do the air intake/air cleaner setup. With the 1.5" "spacer" in the pics, it JUST barely fit the hood. Enough that if another set of motor mounts is slightly different it might cause issues. Maybe I should just make my adapter/spacer out of a 2x6? lol

You made me think of something else though...I wonder if I could just have the TB "pad" milled right off this intake, and start with a flat surface? That would solve pretty much every issue. It's a single plane intake, so if it's cast as I suspect it is, that may be viable, although no idea what that would cost me to have done vs. the adapter/spacer I will need otherwise.