Does anyone know if the TPI base for an 86 and a 89 are the same. Mind you I know the intake bolt holes are at a different angle, but that is what I want. I located a nice set of heads but they are 87-95. I want to change the TPI base and switch everything else over.

 

Im not sure what you mean bye lower plenum. But the only difference in the intake in f-body between 86 and a 89 intake would be the inner 4 bolt angle but the holes can be elongated. The 89 intake does not have a provision for the ninth injector cold start timer switch.

 

Ah ok. I wanted to make sure there were no other differences between the bases. What I want to do is use a newer base for the tpi so I can use newer heads.

 

http://www.hotrodlane.cc/Streetstories/choosetpi1.htm

 

Thanks for all the info man. I am assuming that if I use a TPI base from later than 88 there is no cold start injector and I would have to make changes to the ecm.

 

you can drill and tap the plenum for the timer switch, or got to 89 $6E programing and buy a csi delete kit just to make sure the csi isn't leaking.
http://www.ebay.com/itm/Chevy-TPI-SBC-Cold-Start-9th-Injector-Block-Off-Delete-Kit-/380661635968?pt=Motors_Car_Truck_Parts_Accessories&hash=item58a1339b80&vxp=mtr

 

Hey thanks for the fast responses. What I ended up doing was finding a decent priced TPI base for an 88 camaro with cold start injector. Didn't want to mess with compatibility. But this information is still very useful should I ever decide to delete the injector. Thank you so much!

 

If you do decide to go to the 89 programing lmk I offer reprograming service.

 

Delete !