Finally started pulling the 300 apart, and have lots of questions. 1. Can these ports be opened up much? 2. There is a dimple with corresponding hump in the head, and I don't know why they cast it in. Seems to me it would raise hot spots and cause detonation. Any benefits to it? Grind it off? 3. The valves are close, and not much room is there to put in larger ones. Is any small gain worth the trouble? 4. The top of the bores are cut to unshroud the valves, which I have only seen in built engines. Was this the factory design? The more I look at this engine, the better I like it, small efficient, and well-designed.
For 300 aluminum heads only, Corvair valves and seats will give you 1.720 inlet, 1.500 exhaust. Springs/retainers from Buick wortk with them, must use Corvair keepers as they are multigroove, instead of single flat type stock Buick. Corvair valves are same length as Buicks. DON"T take the stock guides out of the heads, open guides for solid bronze guide inserts, not split inserts. The macine pads can come out of the heads if yo wish, all they were there for was to locate the machine that cut the heads at the factory from raw castings. Ports can't go far, and there is water between the inlet and exhaust ports quite close. Iron heads have vastly different ports, valve sizes, heat crossover, etc, NO head parts interchange. Rockers, shafts do. I have a bunch of bare unmodified 300 aluminum heads if someone needs them.
Have the iron heads, 1.375 and 1.812 valves. Could I go up to 1.5 and 1.812? Would it make much difference, and be worth the cost? Or would the shrouding of the valve perimeter offset the additional area? And am I asking too many questions? Anyone ever flow these heads to find out what improvements can be made?
300 heads the heads on my race engine have stock valves in them, had them back cut to thin the heads a bit the valve bowls hogged and blended and alot of carefull port work my 2900# car runs in the 12.60's my point i guess is ya don't have to mess with them to much (they are the aluminum ones)
BuickCityPsycho, I am curious what is your full drive train. Motor mods, trans, and rearend. Thats very fast for 300cid in a heavy 64 buick. Just wondering.:grin: Julian
julian BTW pinhead64US has a set of headers for sale in the parts forsale section 12 second recipe . (1) 64 special 2 dr post model (2)..030 over 300 block zero decked and oiling mods polished std. std crank recon. stock rods w/ ARP bolts (for a 283 chebby o No: ) they fit!! Badger 11:1 pistons valve reliefs and tooling by me (3)custom ISKY solid lifter cam TA adj. pushrods TRW new castiron rocker assemblies (4) heads as described in above post (5) modified Huffacker 215 intake 650 holley HP ser. carb (7) TH350 (trans brake this winter) hughs 8" custom convertor (8)72 buick 8.5 housing ,spool,4.10:1 gears The car weighs 2890 with me in it. the hood , decklid and rear bumper are fiberglass ,doors and the rest of the front will be in the next year or so. Honestly i don't know why it runs so well but it does
TRW Rockers Hey Sean; Good to see you're still alive and kickin'. How's the new house coming along? Are the cast iron TRW rockers specifically for a 300? Mark
300 rockers Ouch, sorry to hear that. I never thought that I would see our economy so F'd up as it is today. Unless you're a millionaire, everybody is getting hurt by this. Where's the business leadership, I ask you?
Sean, sounds like your engine revs high. What is the rev limit? And, are the factory aluminum rockers bad, or just wear too much?
i shift at 6000 and the limiter is set at 6200 and i used the cast iron rockers because i had them , i'm sure they are stronger also
Hey Sean, I recall meeting you and your machine a few years ago at the Buick Nats. in Columbus, and being very impressed by your setup. In fact I have been searching online for a while to find you and get your 300 recipe. I have a 64 Special as well as an RX7 converted to Buick 300 V8 power that I have been working on. Any chance you would be interested in building a 300 to sell, or doing the machine work if I brought one out your way? Also, how much higher does your carb sit with that modified manifold and added metal work? Just out of curiosity has this thing seen the dyno in or out of the car? Kevin
kool kool on the RX7 i been keepin an eye on a TR7 convertable it sits next to a garage at the moment it would be waykool with a 300 inch stroked 215 in it i have an engine core in the corner. the car has been on a chassis dyno 275 hp at the rear wheels actually the carb sits on a 2" spacer otherwise it would be an inch or so higher than a stock 4bbl intake. i wish i had the time to build myself another engine, fortunetly i havn't needed to,
The Holley Pro-Jected 215 derived engine in my Vega, with 5 speed, daily driver, 13 inch tires, 3.08 gears in the rear end, runs 12.30/104. I drive it to and from the race track, as I said, daily driver. The new engine will be a Rover 4.6 aluminum cross bolted block, P76 crank with 3.500 stroke (if it ever gets here from Austraila), narrowed CAT small block Chevy small journal H beem rods w/floating pins, forged Ross pistons, 3.736 bore, Crower cam, double row timing chain, mildly ported 300 aluminum heads, Isky springs and retainers, Corvair stainless valves and oversized seats, tuned port Rover EFI intake manifold w/Mustang 19 lb injectors and 2.300 inch Chevy dual plate throttle body grafted to the Rover inlet, one of my small body HEI's, 5 speed, 3.08 rear gears, 13 inch tires. Power steering/tilt wheel, power 4 wheel disk brakes, just a street car. Nice light chassis and engine/trans. All that stuff, and the engine still weighs less than 350 lbs, complete, less trans/flywheel/clutch.
