Hello all , My first post to your board, and I might add this has to be the best GM Tech site on the internet. My question is if the Tbi castings are the same in the 1 11/16 inch bore size and are these the same for 305 and 350 engines and also same or different between the car and truck units.Seems like there are a million different part numbers. I need a core casting to use for the high flow mods, will be using on a 98 Vortec 350 long block using a adapter plate on either the performer vortec intake and external Caprice EGR or the GM performance parts vortec with the built in EGR and pipe to a header fitting . I am looking for a LT1 cam and plan on using the stock roller lifters. Thanks for info and suggestions, Dave

 

I think all the 305's had 1 11/16" and the caprice 350's had 2" along with the 454 trucks.

 

that sounds correct, all small blocks had 1 11/16's or 42mm. the only ones that got the 2" unit where the 454's, and some caprice cops. i dont know if all caprice cops had em.

but i havent researched the caprice cops.

anyway, no, they arent the SAME, but they are all close enough to be completely interchangable. only difference ive seen is are cosmetic, not functionality. besides a few goofball looking linkages from older caddys.

 

there is a difference in some of the small block ( 1 11/16 ) TB's. on the 87-90? they use the flat style throttle position sensor, like tpi cars use. in 91 and 92 they used the smaller style tps.


lata
tim

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None of the cop cars came with 2" bore. If they did then we would have a source for small block 2" bore intake manifolds. I don't know of any except for the holley projection manifold.

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, Jon (350 TBI!)
91 Red My website

 

All three of my TBI units differ only in the TPS mounting. All are 1 11/16".

The 9C1 Caprices didn't have the 2" TBI, at least none that I've ever heard on at Caprice boards and here over the years.

 

Thanks for the info- I have 2 TBI units on the way from E BAY I can start tearing up........

 

Dang, I know more than once I've seen caprice intakes advertised as 2" bores. (ebay) Sorry about that. Thanks for enlightening me, lol.