Getting ready to rebuild the engine in my '64 Special with a 300 in it. I have procured a 4bbl intake to replace the stock 2bbl. I also have gotten a rebuilt Q-jet to go along with the intake. I'm looking for any other suggestions that anyone might have. Thanks Greg
300 rx greg : make sure you have a q-jet intake . i don't know if i've ever seen one of those ? make sure it fits the heads etc correctly . some of the later 340 etc motors were a little different i think and they did have q-jets i think . those are nice little motors , had a couple and they always ran fine . be careful with cam selection ( ask a lot of questions ) and don't skimp on the rest of the valvetrain . that and a good dual exhaust system and decent ignition set-up and it should run good . you don't have to go nuts with the ignition right away - even the stock points style done correctly and "curved" by a good tech will be fine . upgrade from there after everything is coordinated - smooth - dependable . make one upgrade at a time and keep track of what works and does not work . have fun . del
There were no Q-Jet intakes made for 300s. You'll need to use an adapter, but then you may run into a hood clearance issue...all 300 4 barrel intakes were square bore, as the Quadrajet was introduced in 1966 (I believe), and the last 300 4 barrel was made in 1965...
The 340 4-bbls are Carter, not Q-Jets. An Edlebrock performer is a Carter-type carb and good upgrade.
Here's what I got when rebuilding mine: NOS rocker arms, shafts, & valves from buickfarm.com (cheap but I don't know if they have anymore) NOS Pistons from Ebay auction 10:1 compression (I think there are some on ebay right now as a matter of fact for around $140) New Crower Camshaft (part #50231) power range 1800-4500RPM Crower dual valve springs, retainers, lifters & valve seal kit Melling pushrods New Timing Cover (Still available from GM) Timing indicator for above cover (yes, the timing marks are sold seperately from GM) Crane double-roller timing chain New Oil Pump & Booster Plate (30 PSI pressure at idle) Felpro Gasket set Edlebrock Performer 500CFM 4bbl - AFB remake Postons headers (I hear they are available again for the 300) 2.5" flowmaster american thunder mandrel bent dual exhaust Can't remember on the rings, main & rod bearings, cam bearings, etc...all this provided by the machine shop The car is a blast to drive, fast & powerful! A few major hurdles I ran into: If you go with the Poston's headers & make the 4speed switch, the header on the driver's side will have to be modified to go around the clutch z-bar. I pulled out the ST300 & put in a saginaw, and ran into this problem. I also changed to cast iron heads & 4bbl intake from a '65 model, this caused a problem because the two blocks are slightly different. There's a coolant port on both sides of the block for the 65 & only passenger side of the 64. When I bolted up the heads, there was a water jacket overhanging the block & spewing water right out on the drivers side, of course it wasn't noticed until the engine was a together. The solution was to plug the jacket on the drivers side head. Lastly, when using the Edlebrock AFB with the '65 Cast Iron 4bbl intake, I had to use a 1" carb spacer in order for the throttle to clear the intake. Otherwise the throttle arm on the carb wouldn't rest at idle. Not sure if you'll have this problem if you have an aluminum intake. Good luck with your rebuild!
John, GREAT info...thanks. I plan on doing a little work on my 300 this summer. I have actually picked up a set of 64 aluminum heads (wooohooo!) that I am going to have cleaned up and a valve job done on for the rebuild. Then I Have also procured an aluminum 2bbl intake (not sure where this came from or what year) and I want to run a holley 500 cfm 2bbl or a rochester 2GC if I can find a nice one. Poston hase some nice cams, and that's a possibility, and I'll have to find out about those headers from poston because I didn't see them in the catalog anywhere. I will also be going with the flowmaster dual exhaust set up. Anyone have any idea wher3e I can find torque specs for aluminum heads and/or intake ?o No:
