View Full Version : Will a 421 Tripower fit on a 389
Hey Pontiac Guys,
Got a question. I have run across a fellow that has a tripower that came from a 421 motor. I am considering buying it for my 389 GTO motor which is a 1966. Will this work without issue? What should I check for and be aware of with this type of purchase?? He only wants $350.00
Hey Pontiac Guys,
Got a question. I have run across a fellow that has a tripower that came from a 421 motor. I am considering buying it for my 389 GTO motor which is a 1966. Will this work without issue? What should I check for and be aware of with this type of purchase?? He only wants $350.00
Old Man Taylor
02-01-2002, 05:12 PM
The manifold will have to be a 65 or 66 for it to work on your engine. If it is a 61-64 you can buy it and look for a 65 manifold to put the carbs on. It would still be a pretty good deal, assuming it is complete. If it is pre 61 I think all three carburetors will have small throttle bores, which you don't want. The 65-6 manifolds do not cover the back of the heads, whereas I think the early ones do. Jut count the bolt holes in your current manifold and compare that number to the one that is for sale.
It would be a good price if the carbs are actually tripower carbs.The tripower end carbs will have no mixture screws in the baseplates and the airhorns will not have choke plates.It also helps if the throttle shafts aren't frozen.
Tom
WARIARGTO
02-01-2002, 09:29 PM
The carbs alone are worth $350 if they are original 421 TriPower carbs. The TriPower 421 came out in '64 I believe (or '63), and ran through 1966. I run '64 421 carbs on a '65 intake in one of my cars. The 66 421 had all 3 carbs the same size, like the 66 GTO 389. The 64-65 421's had the same setup as the 64&65 GTO- small center carb, big secondary carbs. The 65-66 Tripower intake manifolds are still found for around $100-$200 bare. If the setup you have found is complete, make sure the fuel lines and linkage is all there to reuse. Otherwise you'll need to pop for the repros. And the aircleaners are running about $100+ for a set these days also re-popped. If you have happened to find a complete 65 or 66 421 Tri-power, you are in the best position because that whole setup will bolt right on your motor. The only other thing to consider is your linkage, whether you want to run vacuum secondarys or mechanical.