Many guys have been touting the strong points of a 350. They're not wrong, in terms of bang for the buck. For me and for the use case I have described, 350 is too big. 283 is perfect. 305/307 is not bad. 327 is right at the upper limit. I understand that the $$$ will be different, and I am not in a position to spend one more dollar than necessary. I do have a couple of years, so plenty of time to scour deals. I would for sure like to learn about these 'little' 305/307 motors.
Here: http://www.jalopyjournal.com/forum/showthread.php?t=712197 Here: http://www.jalopyjournal.com/forum/showthread.php?t=706094&highlight=307 Here: Not mine but really good info http://www.jalopyjournal.com/forum/showthread.php?t=45615&highlight=pig The pic is a dyno sym of my 307 The numbers are good- but you'll notice the volumetric efficiency never breaks into the 90 %s with the 305 heads. It's all in what you want and how you look at it, when I compare those #s to the dollars spent to get them - the numbers are phenomenal!!!
Here's a 327 idea I've been plating with. 96-2001 vortec roller block with 3.25 stroke and 327 pistons. Well over 400 hp. The 307 above actually has better number in street driving mode where Rpms are generally below 3500 any way. You just figure out what fuel a 307 burns at those Rpms and what fuel a 327 burns at identical Rpms, ok got it? Now look at the power levels. Decisions decisions
If you were to put these two in an overall competition that encompassed all facets- Cost to build, cost to run, longevity, performance, power out put, smoothness, everything... With a 3500 rpm limit- the 307 would win hands down and by a bunch ! The question you need to ask is how much time will you spend above 3500 rpm vs below 3500 rpm.
Be careful with Desktop Dyno. My motor was about 75 HP short between desktop dyno & a real dyno. 307 is a nice motor, but a 327 is better is his application. A 327 will also have a better resale factor.
Yes that +/- factor is true about any sim' but its better than guessing. I believe the question was from JP not 49ply "how did 307 with 305 heads compare to 307 with vortec heads." That's the two close comparisons I had. If you agree to a 3500 rev limit, ill put my 307 against any challenge you can come up with. The numbers are there- 350 ft lbs torque average between 2000 and 5000 Rpms isn't too shabby and that's 307 fuel consumption not 20% more 350 fuel consumption.
Ok I'm going to chime in here with the build I came up with for my 40 pickup. A $50 305 from an Impala. A set of 305 HO heads cleaned up by a shop in Llano with Corvette springs $325 all in when done. A Comp cams 4x4 torque cam kit. A converted dist from GMC Bubba - traded in some cores for credit. A 4GC and iron intake from a 62 327 by the tag. Rams horn manifolds with the angled flange so the exh. pipe routing is easier. Backed up by a NV3500 5 spd and 3:42s in a 10 bolt. Now heres the way I decided on this combo. The long stroke (3.48 = same as 350) with the small bore keeps the charge velocity high. This is the key to efficiency. I had the same combo (but w TBI) in a 95 GMC Xcab and nailed 20 mpg regularly. I could pull a trailer easily bc of no power loss through an automatic. High velocity, squeeze it tight (9.0:1 for todays crap gas) completely burn the a/f charge with a hot spark and exhaust it quickly. THATS how you make efficient power. posted via smoke signals made with a Mexican blanket
Sounds pretty good. Now take it a step further: is there any advantage to using different intake and exhaust rocker ratios? Shorter intake and longer exhaust - - - ?
Nah. Just pick the right cam in the first place. posted via smoke signals made with a Mexican blanket
Sorry, Big Foot it was done in 71-72 by a few friends of mine in AutoMechanics class in school by that time. But, earlier yes you are correct. By that time we were able to get custom if we wanted it and yes the the pistons were made for doing the 301's by then.
Use 283 You could play it safe and go 292 or use an early small journal 327. It really was a fun way to go. We did our own valve grinding and honing and block boring. It's too bad today shop classes are not there for kids to learn mechanics like a long time ago. They took it out of schools.
I do not want to derail the thread, but I have a quick question. can these small engine combos handle a tunnel ram with 2 four barrels?
there are some WCFB's that are 400 cfm, once you get larger... I do wonder what pair of Rochester Quadrajets, w/tiny primaries would do.
depends on application, the original crossrams came out in the 283 era, and it is pretty much the same principal. Honestly crossrams/tunnel rams are high RPM intakes, made to come on strong at 3000-3500 and again at 6000-7000, mostly racing stuff in any application I don't figure it'd change what rpm the pulses hit the valve, runner/plenum size vs the amount of air pulled would be the only different factor. Some stories tell about guys glueing chunks of wood in the plenum and runners to shrink them. Also the '69 z-28 302 had a crossram option too...
I'm getting closer to the point where I might be in a position to begin watching Clist for deals. There have been a lot of good suggestions so far. Tell me if this is a correct summary of the leading alternatives: - 283 with 305 heads and so on (post #53) - 305 with 305 HO heads (post #100) - 307 with Vortec heads or 305 heads (posts 55, 58 and others) Plus, there are invaluable build details in several other posts. $$$ is an absolute issue so I doubt I'll end up with a 283 as they tend to command a higher price. Comments?
The HAMB classifieds had a nice selection before the change over. Post a wanted, just to see if there is a great deal near you.
If you're looking for low RPM torque forget the 283-327 engines. It is far cheaper to build a good 307 or 350. Invest a few bucks and have the rotating assembly balanced if you worry about smoothness.
Look around and see just how man Flathead engines are running around,as long as you have a good block it will give you many years of service. HRP
my 32 has a 283 with a mild cam and a 3.00 gear. it gets down the road just fine and pulls good from stop. I thought about a 350 but the 283 is more traditional than the typical 350/350 combo I see at every cruise night.
So far so good: The engine was inexplicably missing one push rod. Inside looks good. Very slight ridge and can almost see the factory honing marks. The thermostat had been removed. Some scale in the water jacket between the head and the intake. Mud wasp nest inside one chamber but no water damage. Engine had steel shim head gaskets and it did not look like the heads had ever been off. It must have been an automatic since there was no pilot bushing. Everything easily came apart. The lifters are very worn and the cam looks somewhat worn. The nylon timing gear looks good but the chain was stretched. I stripped it to the short block but have not opened a bearing cap. The crank/rods/pistons turned easily with no hard spots. I'd post pictures but it seems there is an issue in terms of file size. Resizing photos is so 1990s.
Cool ! You'll probably want to use a steel shim gasket again - the tight quench will help with smaller cc heads. Don't surprise me what you are finding. They were not performance engines, so baring lack of maintenance issues its likely to have had an easy life. Cam, lifters, gears and chain are junk right from Chevy. Pull the freeze plugs and take a peak for scale and sludge in there, it settles so if you see it at the heads ....
The Jalopy Journal
