Hey guys, not here to often but when i do have a question its answered quickly and perfectly, lol.....and i like this forum too Anyway, im doing a TPI swap on a customers 19809 el camino...91 setup, and the plenum does not have the triangle shaped hole in teh front, from what i read this is normal. But ive got no IAC control, and looking at the throttle and the plenium i do not see how air is supposed to get into the plenium from the throttle body. I think the throttle is aftermarket, it looks to be anyway. Anyone got pics of a late throttle body so i can see where the IAC holes are?! I see the one in front beween the throttle blades, behind the air foil, but the back has the triangle hole in teh center, and sop slots or anything for air to go anywhere. What am i missing here??!!

Mark

 

If the throttle body matches the plenum it'll work fine. If you use an early throttle body on a late plenum you'll have problems. The late throttle body works with both. At least that's what the TPI Swapper's Guide says...

 

Thats what I thought, funny though as i read on TPI swap threads on other sites that throttle bodies are interchangable...which doesnt make sense. Hes got an aftermarket throttle body by TPS, so il call him up and have him exchange it for the right one. thanks man!!

Mark

 

I haven't compared an early/late TB close enough to tell what's different. The only TB I've got laying around (not bolted to a plenum) is a Holley, so I can't really give a more concrete answer without digging a TPI out of storage and pulling the throttle body. It's easier (and probably safer) to just go by the book. I know they changed the TB gasket when they changed the plenum. The later gasket is open between the triangle area and the TB bores. I'd assume that was to allow the center port in the TB to feed into the plenum without the center triangle hole, but I can't say for sure. I've just always kept the throttle bodies matched to the appropriate plenums on my cars.

 

You should be able to drill a hole in the plenum to match the throttle body so the IAC can get some air in order to function.