The addition of 4 barrel won't really gain "seat if the pant" gains. Its still the same engine only with a bigger carb. Power timing will gain Alittle. A 2200 convertor and a 3.08 or 3.23 gear will also show an improvement. Its not just making a lot of power but the rest of the parts being able to use it. You can make a 2 barrel engine outrun a 4 barrel with the right combo and tune. My opinion is to pull heads and mill them .060-.070 . and do some bowl porting for best gains. Lower end torque cam like the Crower cams or a custom Scott brown cam. Consider the convertor and rear end upgrade to enhance your combo.
That is exactly what he is saying! Just because he didn't include comparing WOT to WOT that the 2bbl will give better low end torque doesn't mean you have to call him out on a technicality. So yes when a 2bbl is floored the car will jump off the line faster than a 4bbl even a Q-jet when its floored to WOT, after RPM is in the higher range is where the 4bbl will shine, oh I should add so I don't get called out on a technicality, @ WOT. You knew what he was talking about, so why are you trying to be so confrontational Tony? You must be bored today? LOL Derek
Yes, the gearing change is my next upgrade. I plan on going with the 3.23. I found a used rear end with 3.73's in it, do you think that would be too much for highway running? Is the converter change really that important? I did upgrade my ignition and followed the power timing thread, that was a big improvement. I want to shave the heads to raise compression but not this year. One upgrade per winter. I think the rear end will be next year, then maybe the heads the year after. Thanks again.
3.73 gear would be fine but better if your running a taller tire . 15 in rim with 27 or 28 would be good. Something like a 255-60-15 or 275-60-15 or say a 17 or 18 rim with a tall tire.you can cruise 60-65 with 3.73 gear. Rpm will be abit high. With the 3.73 convertor isn't that important. But if you think about it like this ,say you have stock 1500 convertor and that your engine has say 50hp at 1500 then you add a 2200 convertor where your engine is making 90 HP. (Numbers are just for explain) your car will 'launch' harder as engine has more power and momentum. But if you intend on changing cam. Best to wait to see what cam itself will require. That's where covertor change will be important. But 3.73 can compensate some as rpm will come up fast.
Oops, not confrontational...avoiding misleading generalizations. Of course I knew what he meant. This isn't a discussion to dispute, only for the benefit of the OP. It's quite a bit of work to see minimal differences either way, as mentioned...seat of the pants. The big gains come as you execute things in stages, like heads, cam, exhaust, or top end work. Agreed on timing changes being bigger bang for the buck, esp with a superior atomizing carb. You can definitely tune either to out do the other! The 4 bbl's TEND to deliver better part throttle performance, esp. along with some easy tuning changes. Gears multiply torque for sure! Makes the car seem lighter. 3000 rpm cruise speeds CAN be tuned to deliver more than 20 mpg still. (Much more if you know what you are doing) Sorry for that generalization! Yes there is a LOT more than meets the eye on that one!
It's all good... Here is the scoop: The 2bb has an advantage over the 4bb at low rpm because it has more air and fuel available as the 2 barrels are larger than the primaries of the 4bb. That is the only advantage the 2bb has. Once at full throttle the 4bb has the advantage however there is a narrow power band that the stock 350 really needs the extra air and fuel. Let's say from about 3400-5000 rpm the 4bb will shine but the peak hp of a stock engine is about 5000. Add a larger cam, headers etc and the 4bb will give more gains. On the street the 4bb is great as it can give better fuel mileage.
Did that swap back in the day . would not say it shined. A 2800 stall(was solid 2400 on '77 350) was the biggest gain for me . would have liked more gear and compression but didn't know about how to back then.
You guys must have missed my comments on 2 barrel performance in that other thread not too long ago. Another advantage a 2 barrel gives over the 4 barrel is partial throttle performance (the Rochester 2g anyway, when compared to the Quadrajet), as well as better fuel distribution. Keep the RPMs down on the 2g and you can get decent gas mileage. A couple MPG or so worse than a Qjet. I guess others disagree, but I had two 350's side by side, one a Quadrajet and the other a 2g, and so compared the differences first hand. Up to 4000 RPM, the 2g outgrunts the Quadrajet. Beyond 4000 RPM, the Quadrajet wins. Increase the size of the 2g, and the differences become 4500 RPM instead of 4000. The 'on paper' specs you can pretty much toss over your shoulder. They're as far off as the actual compression ratios. Bump compression on a 2 barrel engine and the HP isn't that far off from a 4 barrel at mid RPMs. It's high RPMs where the 2 barrel meets its limitations, as it cannot provide the airflow a 4 barrel can. The (large base) 2g is an absolute beast at low-mid RPM on a Buick 350. One is not necessarily better than the other, they just have different applications/strengths. A tall highway gear or an overdrive trans would work great with a 2g, where the Qjet would like more of a performance gear. Etc. etc. etc. Gary
It's more like 4500-5000 on the larger 2gs. Not much difference at all. lol These guys must not have heard about the racers who use these carbs, along with Holleys, for the 2 barrel ruleset. Some of them are spinning 6500+ RPM on those hogged out 2gs. Not something for street use, but it's still impressive what the humble 2g can do. I actually did some testing with my 350s by tying off the butterfly flaps on the Qjet and comparing the performance of just using the primaries vs the 2g, and the 2g was way stronger. And that was the factory 2g. I put on a larger 2g and it kept up pretty well with the Qjet even at higher RPMs. Both engines were stock. Adding larger cam, headers, etc. for increased airflow and the 4 barrel will certainly outshine the 2g, but only at higher RPMs, providing you had the converter and gearing for it. Who'da thought. Gary
No doubt! As a matter of fact, if one were to try to build a 2 barrel engine and wanted more grunt than the stock cam, the Crower level 2 fits the bill nicely, with its 1500-4000 powerband. A premium fuel engine with this combination is capable of well in excess of 400 ft. lbs. at around 2500 RPM. Recall the statement made some time back by a fellow board member (to which I concur) about massive low RPM torque and tall gears. Gary
I was thinking the level 3 cam with 4 degrees advance. Steve says cam runs out around 5200. So advanced would bring it down a few hundred rpm in theory. Work the 2gc for Alittle extra cfm. Easily clear 400 lbs thru most of the power band with a 2 barrel. Maybe Alittle porting on exhaust ports for extra push out. 3.23 gears.
That would work too. 5200 was with a Qjet and retarded install though, and it's 50 RPM per 1* if memory serves. You can get 600 CFM 2gs, but that's with 3" and not 1.5". I reckon about a 4700-4800 RPM peak zone with a more common 500 2g and the level 3 cam. Low-mid torque figures would be off the chain. Use the polished manifolds (or better yet, small primary headers for max output) and mandrel head pipes up to "X" pipe and it's sure to perform like a (small) mild mannered big block. The Buick 350 is pretty much this anyway. Gary
A 500 worked with a milled air horn should net some really good power. Possibly see a peak torque near 450? That's big block torque.
Gary, I had read your recent threads on the benefits of the 2g, that is what I referred to earlier in this thread about fear of not getting the seat of the pants results I am expecting. One last question to you guys as you all seem very schooled on these engines. Is it worth the extra $ching$ to go with the TA performance intake or will the factory cast intake give equal performance???? Thanks.
Thanks Sean, that was a great thread that pretty much answered my questions. I plan to end up with a good running street car. All you guys on this site have shown me the direction I want to go. 4 barrel swap has begun. I did an ignition upgrade with power timing. good 2.5 exhaust, check. next will be gears, 3.23 or 3.73 not sure with converter change. shave heads. headers. and a good mild cam. Little bit at a time while I drive and enjoy the car. Thanks again for all the help and direction.
Second question first. The TA Stage1 intake is a good choice for stock engines, but don't expect vast improvements over the stock one. The TA intake is better suited for engines that flow more air. Biggest difference you'll see is weight savings on stock-mild engines. This is enough for many, since the width of the Buick 350 intake is as such that makes the intake weigh more than a Buick 350 head (in excess of 50 lbs. (some close to 60, depending on year model!), stripped down bare). TA Stage1 dual plane intake is supposed to weigh 16 lbs. stripped. A '40 lb.' weight savings is typical. First statement: With a tall street gear and stock converter, the car will take off slower with a Quadrajet than with a 2g, since the torque band is moved up higher in the RPMs with the Qjet. This is one of the reasons the engineers used lower numerical gears with a 2g than with a Qjet. You can mix and match anyway you like of course. Raise RPMs with gearing and stall, more duration on cam and compression properly matched to it, air flow optimized with headers, etc. and the Qjet will shine. The car will be super fun and fast. Unless you use a numerically higher gear ratio and/or increased stall speed, the Qjet will slow you down. I'll probably get flamed for saying this, but it's true. Gary
When switching to 4 barrel I suggest a quadrajet or holley and at 750 cfm. The edelbrock carbs are not easy to tune . fuel calibration is not correct for these engine. Can make it work but better options available.
