I need some advice about 389 Pontiac. The customer has an engine, he brought me a triple two barrell complete with carbs etc for rebuild, it is the early version with smaller primary carb. He says the intake doesn't fit the engine, he needs newer intake that he says is longer. Is this right? i thought they were interchangeable thru 421 possible to 455 If I get a newer intake will these carbs work or is the primary a larger base? Thanks, OJ
There are three different series or Pontiac manifold and head combos. You need to research exactly what yu have before going too far. There are several good Pontiac and tri power sites. Sent from my SM-G550T using The H.A.M.B. mobile app
How cheap is cheap? I could be interested. Pre 64 intake? Sent from my VS990 using The H.A.M.B. mobile app
64 and down 12 bolt water passages difference 65 up 10 bolt theirs sum over lap in 64 gto and performance cars got the new intake design aka 10 bolt. Theirs a difference later on with the cross over if Im remembering right Pontiac tec thred https://www.jalopyjournal.com/forum/threads/tech-pontiac-engines.224124/
64 and older Pontiacs are pretty much the same and 65 and newer are pretty much the same. Yes, there are differences that might be important, but for a general rule, that is the easy thing to remember. The biggest question is what engine do you have? Hit Wallace Racing for a rundown of casting numbers. Once you figure out what year your 389 is and if it is actually a 389, then we can help you from there. http://www.wallaceracing.com/engine1.htm Remember, Pontiacs are kick ass engines and Chevvie logic does not apply to them at all. We will get you through this Pontiac deal and you will love it, I swear. Good luck, -Abone.
Intake should match the heads. I have heard of guys putting later heads on earlier blocks for the larger valves and ports. KK
OJ - here is a link to factory Pontiac tripower information: http://www.thecarburetorshop.com/Tripowerspecs.htm Here is a link to known O.E. and aftermarket Pontiac multicarb manifolds: http://www.thecarburetorshop.com/Pontiacmultiplemanifolds.htm In general, 1955~1960 FACTORY intake manifolds/heads will bolt up, 1961~1964 intake manifolds/heads will bolt up, and 1965 to (I think) 1970 intake manifolds will bolt up. Somewhere around 1971, if one uses an earlier manifold, one has to play with the hookup to prevent an exhaust leak. Some of the aftermarket manifolds may be used from 1955~1964 by changing a plug. Just because a manifold/head combination will bolt up, doesn't mean one will have a viable compression ratio. Two outstanding inexpensive paperback books are available; one by Pete McCarthy, the other by Jim Hand. Oh, and 1957~1958 have 3 small carbs, 1959~65 1 small (center) and 2 large (ends), and 1966 all 3 are large. Jon.
389 was from 59-66. Several changes along the way. Best thing to do is get the head cast number off the two center exhaust ports. We can go from there.
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