Ok, I'll absorb this information and see what I can come up with. I do notice that the 300 heads seem to have a similar flow pattern that the 350 heads do in that the flow flattens out around .400 lift. Those are seriously ported heads (level 3 for iron and level 4 for aluminum), and still didn't gain a whole lot above .400 lift, so I'll assume untouched heads will pretty much dead end at .400 or so, not unlike the Buick 350. I can use this data. It's exactly what I needed to form a worksheet for the heads to use in the dyno calculator. Give me some more time to find the cam specs and I'll work my magic. Gary Edit: ok here's the Federal Mogul camshaft, part number CS364: Initial analysis shows the lobes are asymmetric, with 107 intake centerline @.006 and 106 @.050. LSA is 109, so it sits at 2* advance @.006 and 3* advance at .050. On to more analysis...
Low-mid range is where the 2g shines. It needs a lower RPM stall so it can make better use of more of its powerband. I agree, a manual transmission with a 4 barrel dual exhaust and a nice 3 series gear is great for the street. I was talking about the 350 anyway, which is different. We'll see what I can find out about the 300. The story may change a bit, so stay tuned. I try to keep a mental bracket of what is what when referring to 'low', 'med', and 'high' RPMs for street applications. Usually 1500-3000 is Low, 3000-4500 is Med, and 4500-6000 is High. That pretty much covers the vast majority of all engines that'll be street driven. :TU: Gary
Man that's one tiny cam. I'll have to do calculations with other cams later, as I've run out of time for now. I did manage to do a 2 barrel and 4 barrel version, with interesting results. The powerbands are pretty much the same, with the 4 barrel adding a little more power. If one were to use this cam, adding more CFM, whether it be a larger 2 barrel or a 4 barrel would yield good enough results to be used with highway gears. I think though that this cam may be a bit smaller than the factory one, as the RPM peaks are lower than what is listed in the books. More on that later. Anyway, here's the results: Buick 300-2 (using small base 2g) gives 329 ft. lbs. @2300 RPM with 196 hp @3800 RPM. Buick 300-4 (using 600 CFM 4 barrel) gives 336 ft. lbs. @2400 RPM with 209 hp @3800 RPM. (+7 ft. lbs. and +13 hp by adding more CFM) This shows that the camshaft is a restriction, even for the smaller heads. Power bands didn't really change even with twice the CFM added. Compression ratio was 9.4:1 static to match a 7.75:1 dynamic with a 60* intake valve closing point. As you can see, the dyno program is conservative and more real world power is probable. This cam is modified from the original OEM cam I suspect, with more torque and lower powerband for use in A and B body cars. Also shows less horsepower than rated 'on paper'. What this DOES show, however, that you CAN use a 4 barrel if you wanted, and still retain good low-mid RPM power with highway gears. So the story did change a bit. I'll do some Crower cams later. I suspect this little engine will wake right on up with some more air flow... Gary Edit: more info to come. ^^^^ power figures are not accurate here. Have to fix stock head flow data. ^^^^ Stay tuned. Ok things changed. I'm leaving old data up for reference, as the (guessed) head flow wasn't as good as the ACTUAL stock head flow, which was my mistake based on a 'best guess' which didn't turn out to be very accurate based on my limited knowledge on this unfamiliar engine to me. Oh well, it wasn't THAT far off, but still makes a difference, even with the tiny stock cam. Larger cams will make even more difference. Anyway, here's the corrected results: Same as above, same stats, only thing changed was corrected head flow data. Buick 300-2 (using small base 2g) gives 319 ft. lbs. @2400 RPM with 209 hp @4000 RPM. Buick 300-4 (using 600 CFM 4 barrel) gives 329 ft. lbs. @2900 RPM with 226 hp @4100 RPM. (+10 ft. lbs. and +17 hp by adding more CFM) Less torque and more hp with a little higher powerband, as suspected. The 4 barrel setup shows a tighter powerband and a little higher hp peak, still showing cam as a restriction. So 2 barrel is still better for highway gears than 4 barrel engine, as was originally stated, but still wouldn't do bad. So anyway, sorry guys for the flip flop. That happens when assumptions are made without actual data. I guess I won't be doing that again. Moving on, we see a more accurate depiction of the engine's power output, and would be even better with a larger cam, which I'll do later. Gary
Good stuff Gary!! I need to ask though, why did you go with 9.4:1 compression ratio? In '65 the 2bbl sbb 300 was listed to have 9.0:1 compression and was more than likely to have even less, more like 8.6:1 plus or minus (.2) with a non-blueprinted engine. So if its on the low side of that then it would be 1.0:1 less compression ratio than what you ran the simulation at. o No: Can't wait to see what you can figure out with this little gem of an engine! Thanks for taking the time to do this. :TU: If you want to you can even run a few with a set of the fully ported TA Rover heads(I think advertised intake peak from TA is 260 CFM!!) with different cams if you get bored? Even without swapping in a 350 crank the 300 crank can be stroked plus .140" with using a set of nascar take out rods and a set of AutoTec sbb 350 forged pistons would yield with a .050" overbore and a 3.540" stroke the CID would be sbb 321 ready to spin to win! Or with the 350 crank the standard stroke of 3.850" to yield a sbb 350 from a sbb 300. Derek
I'd say Gary's numbers are spot on for a 300-4V. With a tiny stock cam and 10.25:1 advertised compression (more than likely 9.5:1 actual), I have a hard time keeping mine from pinging on 93 octane. I basically have to run 30* total and bring it in no sooner than 3000 RPM. It feels like about a 200 horsepower engine although it is rated at 250. In this case, I've always thought a factory 300-2V with 9:1 advertised (probably 8.25-8.5 actual) would run BETTER in the real world with a 4-barrel carb (my factory AFB is said to only flow 400 CFM) because you could run a better timing curve without ping on our current gas. To make a stock four-barrel 300 run well, you'd really need better gears and a slightly bigger cam to bleed off a bit of cylinder pressure (IMO). I have 2.78s with the ST-300 and it's just a dog off the line. Up around 50, however, it does have excellent passing power.
these are what my stock heads flow before porting. intake 68cfm@100lift, 116@200,159@300, 170@400,173@500,175@550 exhaust 45@100,79@200,94@300,101@400,105@500,105@550. with mild porting we picked up 10.3% average on intake and 11.2% average on exhaust with a little bigger exhaust valve.
Well to be fair, I'm not convinced the numbers I used for the head flow were exactly accurate. I took the numbers from that page Derek showed me and subtracted some from it, so it was a best guess. Now that I have actual hard data for stock head flow, I can go back and fix the spreadsheet and rerun the data. I'll edit the previous post with power numbers results. It may change a bit, but probably not a whole lot. The powerband will probably go up a little though, since 3800 RPM peak is pretty weaksauce, even for a stock cam. I was expecting 4200-4400. Torque may go down some and hp up a little, and will better match what we see on the books for this engine. Ah well, it's a different engine than the 350. I'll do some figures with larger heads and other cams too, just give me time guys. I can do more on the weekend, but during the workweek, time's more limited. Oh yeah, to answer your question Derek, I used 9.4:1 because it was an even comparison between engines, where the only difference was the carb change. It also put dynamic compression to 'ideal' zone (maybe needs to be a bit less for real world usage, like around 7.5:1). With that cam's intake valve closing point at 60*, it closes sooner and creates a longer dynamic stroke, which also boosts dynamic compression sooner, so needs less static compression. This cam is pretty small vs the stock Buick 350 cam, particularly on the exhaust side. I guess they figured the I/E ratio was better for the 300 so didn't need exhaust emphasis. Still, more exhaust emphasis would help draw in from intake on overlap cycle, which would have bumped peak hp up to expected ranges. Most 300's seem to have been 2 barrel engines, so maybe that's why they made it more 2 barrel friendly too. Either way, it needs more cowbell. :grin: Later Gary Edit: went back and fixed the spreadsheet data for stock 300 head. My numbers were a bit off...seems the head was the restriction moreso than the cam, so we'll see what happens when I re-run the caclulations. lol Once all the technicalities are ironed out, we'll have more reliable data to work with. It's getting there. Ok see above earlier post for fixed results. Sorry about the mess.
No hurry Gary, when ever you feel like delving into it. And to be fair with the integrity of the thread to get close to real world results for the 2bbl engine getting a 4bbl swapped on with no other changes wouldn't you think the lower compression ratios in the 8s would make the answer to that question more accurate? Anyway I think that would be a good starting point but its your time and you dyno simulator so you can do it however you want, I'm just glad you're taking the time to do this for the little underdog sbb 300. The design theme of the sbb 300 seems to be from back in the day was to try and make a small CID engine with lots of low end torque? Or with the Nailhead port configuration they couldn't get the heads to flow worth a crap and decided to see if they could make it a low RPM torque engine? They used the same crappy flowing heads for the 340 engine as well, its a wonder that engine could even rev to 4,000 RPM before running out of air. LOL! The correction being the new port layout for the sbb 350, with those heads as cast capable of flowing more than a max effort ported set of 300/340 heads! The Buick head flow philosophe must of changed around then? Derek
That stock cam seems to suit the 2 barrel much better. The 4 barrel setup needs a larger cam for sure. I'd be willing to bet there were two different cams for those engines, though Federal Mogul only lists the one cam, seeing how most (300) engines were 2 barrels. This would make more sense, especially when considering the bump in compression would need a later valve closing point, which the larger 4 barrel cam would surely have. Gary
Well this is for reference, so lowering compression would still have similar comparison results as shown, just with smaller numbers. The power increase and powerbands would be similar, maybe slightly lower due to lower compression. This comparison uses same compression for both engines. Using larger cam/higher compression for 4 barrel would raise powerband and increase the power gap between the two engines even more than this comparison indicates. As I said before, I think the 4 barrel used a different cam with the higher compression. It makes more sense when looking at the power figures and RPM bands. It's a different engine than the 350, that's for sure. Gary
I think I'll put in the stock Buick 350 cam specs into the 300 and see what it does. Should be interesting. Later though, gotta get going. Gary
Thats funny my 340 with the heads I posted would make power to 6000 rpms with a small 216-224 cam and it liked a big 750 cfm carb too
Old engine archeology, I think you're right about the 4bbl having a different cam because this engine was made from '64 to '67 with only the first 2 years being able to order the 4bbl option. That option must not of been that popular and must not of been much of a noticeable difference with the way the 2 engines ran with a 2bbl vs. a 4bbl, must of been why the last 2 years the 4bbl was discontinued? Then replacement part makers like Federal Mogul only remade the 2bbl cam because there were WAY more of the 2bbl versions they figured they would make the cam that was for the majority of the engines built. Little did they even think to consider that even if the 4bbl engine version cars went to the scrap yard the 4bbl intake was sold separate making the majority of the survivors 4bbl engine. o No: If I remember I'll try to make a call the Federal Mogul and ask if they know if there was 2 different cams for the sbb 300 engines. First I'll try to find my '64 chassis manual to see if that info is in there. Stupid time change!!! It got dark WAY to quick today! Derek
buick only listed one cam for the 300. in 1965 lift was 393-401 and in 1966 the lift was 391-401 and in 1967 they listed as 393-399 lift most likely all the same cam. they only listed one cam for the 2 and 4 barrel
As I said earlier, I think Federal Mogul changed the cam specs a bit, and this information confirms it. The Federal Mogul cam is an even pattern .372/.372 I/E on lifts, 186/186 durations @.050, and 266/266 durations @.006 with a 109 LSA. Lobes are slightly asymmetric with a 2* advance @.006 (107* ICL) and 3* advance @.050 (106* ICL). It certainly seems to be more 2 barrel friendly, even though Buick may have only used one cam for both, it was probably larger duration wise as well. This Federal Mogul cam resembles the later model 350 cams that Melling offers (they offer two) which was very small and had a powerband topping out at ~4200 RPM for the 350. The Federal Mogul 350 cam and Melling "GS" cam, which are similar in size, will peak between 4600-4800 RPM, depending on application. This Buick 300 cam is so pathetically small that it's a waste to use it with anything other than the stock small base 2g...which most 300's are. I guess they weren't too concerned with putting too much thought into the 300 as they were the 350, which has an impressively engineered lobe design. A bit disappointing for the 300, to say the least. This is why I was thinking of putting the 350 specs into the cam spreadsheet and seeing what it'll do in a 300. I don't think the cams are interchangeable, but one could custom grind a cam to 350 specs for the 300... If it does as well as it does in a 350, the 300 would be even hotter with it, and might even have a slight lope, all while having a nice, long lasting camshaft. The powerband would be higher for the 300 than the 350, but the heads don't flow as well as the 350, so it might be around the same, I don't know. I'll get around to putting in the specs later. I'm very curious on its performance now. The 300 has a lower deck height and would fit easier into a G body regal vs a tall deck 350 which has clearance issues with the AC duct on the passenger side. The 300 has the same stroke as the 3.8L v6, with almost the same bore. You could bore the 3.75 to 3.8 with .050 over if sonic testing shows it is permissible, then use the v6/350 standard bore pistons...but does the 300 use the same compression height as the 350/3.8 pistons? I know the rods are shorter than the 350's. I remember years ago some guy I knew put a "Wildcat 355" Buick engine into a Chevy Nova and put the thing in the ditch because he couldn't handle the power it had. That was the 11:1 300, if I'm not mistaken. Pretty spunky from the factory. Gary
How does the stock cam from a 340 4 barrel come into play here? same as the 350? Any options that would make a difference by putting a 340 4 barrel cam into a 300 with the 4 barrel swap?
I just checked out the specs at NHRA's website, and they list the same cam for the '65 300 2-barrel and 4-barrel...I have to assume the 393/394 difference is a typo. Deck Piston Type H.P. Disp. Cl Dish/Dome Ht/Vol Valves Cam Lift Springs 155 225 .010 1630/1380 401/401 Outer Only 210 300 .010 1818/1380 393/401 Outer Only 250 300 .010 1818/1380 394/401 Outer Only 325 400 .010 1875/1500 431/431 Outer & Inner 325 401 .010 1875/1500 431/431 Outer & Inner 340 425 .010 1875/1500 439/441 Outer & Inner 360 425 .010 1875/1500 439/441 Outer & Inner
Stock Buick 300-4 using same CFM carb as previous (600 CFM), stock flow heads, and Buick 350 cam specs comes to: 326 ft. lbs. @3100 RPM with 253 hp @4500 RPM. This looks more like what you'd see 'on paper' with claimed power specs, so it's highly likely the actual OEM cams used specs larger than what Federal Mogul uses now. Static compression was bumped to 10:21:1 to reflect the same dynamic compression of 7.75:1 since the intake valve closing point went from 60* to 71*. This is a loss of 3 ft. lbs. at 200 RPM higher, and a gain of 27 hp and 400 RPM over the Federal Mogul 'stock' Buick 300 cam. The Buick 350 cam makes quite a difference! (and shows just how choked off the stock 300 cam was) Now we see the heads as being a restriction, as that same cam in a Buick 350 will peak 100-300 RPM higher. This is stock head flow though. With some cleanup I'm sure it would do better, and remember these are raw numbers without any blueprinting or massaging techniques considered. I'll put in the ported head flow numbers, bigger cam, and some headers later on. I know this isn't rock solid 'proof' of anything, but will give folks an idea of what to expect in a general sense. Gary
Good stuff Gary, thanks for taking he time to compile the info for this, and if you have the time to don't forget the max ported TA Rover heads on a sbb 300, that would be VERY interesting to see what the potential with some air flow would be. In the bold; yes even though the deck height is shorter they kept the compression distance the same and made the deck taller and the rods longer to clear the new crank throws, but kept them short enough so they would actuate enough to clear the cam with the added cam clearanced bolt heads for the sbb 350. They REALLY should of raised the dam cam in the freakin 350 block so they didn't have to do those things and so the dam pushrods didn't have to be longer than the BBB pushrods!!!! As for the '64 sbb 4bbl 11:1 300 in a Nova, the engine was at least 160 LBS lighter probably more like 200 lbs lighter than a sbc so the power to weight ratio was way up compared to a sbc, that along with how light those cars were to start with would of be a pretty good performer I would have to think. I think an all cast iron sbc was around 550 lbs vs. a sbb 300 with aluminum heads and intake was around 360 lbs. I think going from my CRS memory. That would of been a fun car with that engine in it with around 200 lbs off of the front end, it should of handled really well, the guy must not of been a very good driver or he was a yahoo? Or he had bald tires on the car and drove it in the rain, with it being that light it would of been like driving on ice. Derek
