Depends On The Choke Setup and Accelerator Connections
R.W. - I have a 1972 402 block (#3999290),and I have access to a 1966 Q-jet intake manifold and exhaust manifolds. They look like they will bolt right up. Should I use the 1966 stuff or try and swap them out for the correct 1972 intake and exhaust manifolds? Are there any performance considerations?
B._. - As the owner of a 1966 SS with the correct Q-jet intake (3883948), I would have to say it depends on your choke setup and accelerator connection. The choke setup is a divorced well type and uses a thermostatic spring to actuate a lever up to the carburetor choke lever. disconnecting this is no problem if you have a manual or electric setup. The carburetor was originally set up to accept a throttle actuation lever, not a cable, so any mounting holes for accelerator cable bracketry would be missing. Also, you will have to plug the temperature sending boss with a 1/2 inch pipe plug, since the sending unit was moved to the cylinder head in 1968. The original Q-jet intake was installed on 325 H.P. cars and has a fairly deep plenum area under the carburetor mounting surface. I have been told that the configuration of the runners, (etc.) lends itself well to a torque type application but how this compares to the 72 unit, I cannot say. I do know that a 1971 intake is flatter and will not work with the 1966 linkage due to interference on the Powerglide kick down shaft, unless a carburetor riser plate is used. Also, the heater hose supply goes into a hole near the front of the intake facing the water pump, while later manifolds place this further back towards one of the runners. This manifold was also used on 390 hp passenger cars with 427's in 66/67, so it at least will flow that much air. By the way, what are the exhaust part #s? If the RH is 3868874, then these were installed on 65 Z16 375 HP Chevelles and all flavors of 66 396's (325, 360, and 375 HP...)
Archivist: Tom Wilson
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