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 Page 1 of 2 12
Username Post: 283, 307, 327-Which One?        (Topic#197630)
557B210 
Contributor
Posts: 293
557B210
Loc: Jacksonville
Reg: 06-15-08
08-30-08 09:40 AM - Post#1511204    

I'm in the process of tearing down a '64 283 to rebuild and put in my 55 2DR sedan...I also have a couple of 327's (66/67) laying around...I could use the crank out of one to build a 307 (providing the 283 has enough clearance for the counter weights)...Or I could just rebuild one of the 327's...Keep in mind, I'm building this as an "old lady's" car... Max comfort, reliability and optimal fuel mileage...I have 3:36 gears and will be installing a 200-R4 transmission.

My queston is: Which engine, built with a 9:5 compression ratio, mild cam, and either a two barrel or Holley ProJection system will yield the best gas mileage? I'm really not interested in going the LT1/LS1 with EFI route..
david aka POPS
55/57 2DR B210


 
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drummertom 
Member
Posts: 1852
drummertom
Age: 61
Loc: Durham NC
Reg: 09-03-06
08-30-08 09:49 AM - Post#1511212    
    In response to 557B210

I know it isn't answering your question, but isn't a 327 with a 283 crank a 302?
www.picturetrail.com/drummertom

"Well my time went so quickly. I went lickety spickley out to my ol' 55"


 
SuperSport 
Super Senior Member
Posts: 6501

Reg: 07-03-01
08-30-08 09:52 AM - Post#1511214    
    In response to 557B210

Both engines in stock form, the 327 will produce more torque, which helps MPG. The 307 2bbl has more torque than the 283 2bbl.

More torque in a 350, and even more with the 400 sbc.

When you have more torque, you use less throttle position to do the same amount of work.

~SS~


 
557B210 
Contributor
Posts: 293
557B210
Loc: Jacksonville
Reg: 06-15-08
08-30-08 10:36 AM - Post#1511243    
    In response to SuperSport

Mark...Appreciate the input...I believe it can be said that bigger is more, when it comes to HP and torque....However, there has to be a point of diminishing returns, when it comes to MPG.
david aka POPS
55/57 2DR B210


 
557B210 
Contributor
Posts: 293
557B210
Loc: Jacksonville
Reg: 06-15-08
08-30-08 10:39 AM - Post#1511246    
    In response to 557B210

Tom...Your right...A 327 with a 283 crank becomes a 302...However a 283 with a 327 crank becomes a 307
david aka POPS
55/57 2DR B210


 
Impala65SS 
Valued Contributor
Posts: 3741
Impala65SS
Loc: Sweden
Reg: 08-23-07
08-30-08 11:50 AM - Post#1511293    
    In response to 557B210

Right, the 307 has the 3.25" stroke.

I totally agree on the "diminishing returns" -
Compared to the rest of car engines around the world - any of the 283,307 or 327 are ridiculously large engines.

I would absolutely go with the 283 to save gas -and a high gear in the rear. I'd use an OD transmission. Further I'd use a Rochester Quadrajet (intake with oil filler pipe from '67 or '68) for the minimal primaries.

A minimal primary venturi diameter engineered to yield just enough power to propel at a given cruise speed, without hindering butterfly valves, is the most fuel efficient carburator setup you can have. The next best thing are small barrels, where the valves are closer to wide open than shut - at cruising.

Driving around with the two barrel induction means you have unnecessary large butterfly valves for cruising, but a bit too small for performance - a trade-off.

I would try to use a higher CR, 10 or 10.5:1. Higher CR means higher efficiency. Use a thinner gasket, mill the heads if you have to. You gain extra torque over the the whole band. You are not sacrificing anything.
An even higher rear gear ratio lowering the rpm, the surest way to preserve gas. -Even when the engine is stumbling, coughing and struggling, it's taking less gas than a few hundred rpms up - where it sounds better.

Personally I'd use the 327 anyway and set it up along the lines I stated above. Friends with b-bodies and 327s are making 24mpg highway. It's easier to be happy with more cubes
http://www.youtube.com/watch?v=SXn2QVipK2o&a mp;fea...


 
557B210 
Contributor
Posts: 293
557B210
Loc: Jacksonville
Reg: 06-15-08
08-30-08 12:28 PM - Post#1511310    
    In response to Impala65SS

I'm starting to lean more toward the 327 now...Build it with small valve heads (1.7 intake/1.5 exhaust)...180 degree intake manifold with small runners and a quadrajet carb, until I go with a Projection or some other type of EFI system...I'll have to cc the heads I have available with the small valves....I have a 2 sets of the old Power Pack heads....I also have a set with larger chambers, either off a 68 Camaro 327/210hp or a 72 Nova 307...I'll have to see which heads will give me the optimal CR that I'm looking for...Won't I have a problem running regular unleaded with a CR above 9.5 to 1?
david aka POPS
55/57 2DR B210


 
5Larry7 
"11th Year" Silver Supporting Member
Posts: 1749
5Larry7
Loc: Dallas, TX
Reg: 05-17-04
08-30-08 01:15 PM - Post#1511341    
    In response to 557B210

FWIW: You say you have a 3.36 rear end gear ratio. I believe a 2004R has a .7:1 OD ratio. That translates to a 2.35:1 final drive ratio. That is awfully tall, especialy for a 283. It is even worse if you have A/C. There is a point of diminishing returns in gear ratios as well as cubic inches. I think all the above ideas about what cam, compression ratio and carb size are good. I guess I would use the 327, given that you want the 3.36 rear gear ratio. JMHO. Larry
'57 210, Blown 327 cid, Holley HP TBI, 700R4, A/C
'51 Studebaker Starlite coupe, 350, TH400, GV OD.
'96 Replica of a 1950's Teardrop Trailer.


 
Impala65SS 
Valued Contributor
Posts: 3741
Impala65SS
Loc: Sweden
Reg: 08-23-07
08-30-08 01:29 PM - Post#1511345    
    In response to 557B210

Well, gas octane differs - yours in the states and ours in Sweden. Your premium (91 (RON+MON)/2) and our regular (95 RON) is similar in detonation resiliance - I'm not certain they actually corrected the octane rating (likely to be higher than the rating) now with the 5-10% Ethanol in both our countries.

I have no experience of your regular - so i won't say you're fine.
Regarding the premium - the engine configurations using your premium I see in american magazines are similar to the ones built over here using "our regular".
Also I have discussed the gas quality often with a good friend of mine (in the US) who is a skilled car guy (and a senior mechanical engineer) - so I think we have covered it enough for me to be able to compare the US "premium" with our "regular" and those will handle the CR.

It's a matter of cooling and ignition (you will need to back down of course) as well.
I've seen SBC aluminum heads (dissipate heat), angle milled to 53cc for $700 on Ebay.
http://www.youtube.com/watch?v=SXn2QVipK2o&a mp;fea...


 
aerosedan42 
Contributor
Posts: 354

Loc: Oregon
Reg: 07-20-08
08-30-08 01:54 PM - Post#1511352    
    In response to Impala65SS

I have a 327 with the 1.94 heads and a mild cam, it is very fun to drive and used to get 20 mpg highway with a quadrajet and a 4 speed manual with 4.11 gears. When I changed to an edelbrock square bore I went down to 16 mpg and this is in a 57 chevy 150 2 door

 
Impala65SS 
Valued Contributor
Posts: 3741
Impala65SS
Loc: Sweden
Reg: 08-23-07
08-30-08 02:07 PM - Post#1511355    
    In response to 5Larry7

I will agree the tallness of the 2.35:1 would be sluggish if it was there all the time - but it's only in top gear... 9C1 caprice LT1 had 3.23:1 and a 0.7:1 top gear. By the way, the 200r4 is actually 0.67:1 in 4th gear.

Before affecting milage for the worse, you really have to have some tall gears (everything else the same). I honestly don't know, how much is too much, just that it's typically "more than expected".

On the subject of larger engines works less strained thus consuming less:
A friend worked at a brewery and his truck had an inline six diesel of six liters, the typical load was nine or ten tonnes (pretty much the same as US tonnes). Some co-workers had the seven liter diesels with the same load. Those were "woshing" by on uphill roads, of course, and a rumour spread that the seven liters were easier on fuel because of the lighter load on the engine. When fuel records were checked against the miles driven and the loads carried - the fuel consumption was much higher for the seven liter trucks. The driver "community" was of course stunned, but they were a bit too quick to adopt the theory that fitted their wishes better (quicker trucks to finish of the round a few minutes faster, on a whole day).

I'd seriously consider 2.21:1 on my impala and a tbi350/700 (it's resting in the corner of the shop at the moment) if I decide to turn it into a strict cruising car where the milage is a higher goal than 1/4mile ET's. I will try to find L98 heads for it.
http://www.youtube.com/watch?v=SXn2QVipK2o&a mp;fea...


 
Impala65SS 
Valued Contributor
Posts: 3741
Impala65SS
Loc: Sweden
Reg: 08-23-07
08-30-08 02:12 PM - Post#1511356    
    In response to aerosedan42

I agree with the squarebore experience...
I'd say the four speed manuals save at least 2mpg or rather 4 in my experience. I had a Volvo with 4.3:1 and it made 30mpg.
http://www.youtube.com/watch?v=SXn2QVipK2o&a mp;fea...


 
SuperSport 
Super Senior Member
Posts: 6501

Reg: 07-03-01
08-30-08 02:55 PM - Post#1511364    
    In response to 557B210

  • 55B210 delray Said:
....However, there has to be a point of diminishing returns, when it comes to MPG.



I'm not sure where that point is. Examples:

73 Trans-Am 400 Pontiac/auto/2:73 - 20mpg
73 Gran Prix 455/auto/ratio unknown - 20mpg (in a much heavier car)
Don't have the numbers right here, but those two engines are known torque monsters.
36 Dodge w/Nissan diesel- 35mpg (this car takes off easily in 2nd gear)

I feel that any way you can raise the torque number, MPG follows. Example: Bolt on a set of headers, mpg goes up.

Seeing the 3:36 gear w/2004r made me think of needing plenty of torque to run OD/lockup without putting your toes in the carb.

I do see diminishing returns with gear ratios. If you don't have the torque, a higher gear may reduce MPG. Example, 4.3 V6 w/400 trans in my pickup. MPG is higher w/3:08 vs. 2:73. The 4.3 just didn't have the torque for the 2:73.

As mentioned, a Q-Jet can yield better MPG than a 2bbl due to the smaller primary bores.

283 vs. 327, I'd use the 327.
~SS~


 
52chevybob 
Dedicated Enthusiast
Posts: 5628

Reg: 05-27-08
08-30-08 03:58 PM - Post#1511405    
    In response to SuperSport

The rear end is a bit tall for the 200 but you really need to figure out what the rpms are at a 65mph crusing speed. Shoot for a 1900rpm for the best economy for those engines.
The revs/mile times the displacement pretty much determine the mpg of the engine provided that the carb doesn't go into power mode. Rochester 2bbls start going into power mode at about 14" of vacuum and are full on at about 12". A good cruising will be with about 15" and that will get ou about the best gas milage you can get with the car.
Note that a torquey motor will be able to run at a lower rpm by a small degree and a low torque motor will need higher rpms.
My 283 in a '52 Sedan Delivery gets me 21mpg and it has a 3.08 rear end ant a TH400. It's turning about 2200rpm at freeway speeds.

 
GaryC 
Very Senior Member
Posts: 2677
GaryC
Loc: Pittsburgh, PA. U.S.A
Reg: 02-28-03
08-30-08 04:59 PM - Post#1511443    
    In response to 557B210

  • Quote:
Holley ProJection system will yield the best gas mileage?



Unless you already have this, would you ever recover the expense vs. a carb?

Just a thought.
1957 Chevrolet Bel Air coupe, 300hp 327, M20 4 speed


 
jel1957 
"5th Year" Gold Supporting Member
Posts: 431

Loc: Sugar Land, Texas
Reg: 01-01-04
08-30-08 05:52 PM - Post#1511475    
    In response to GaryC

I would build a 302. Always wanted one.

 
557B210 
Contributor
Posts: 293
557B210
Loc: Jacksonville
Reg: 06-15-08
08-30-08 06:11 PM - Post#1511482    
    In response to jel1957

No doubt the 302 was an awsome engine....However, I think it would be better suited for a different application....I think something with more low end torque will fit the bill
david aka POPS
55/57 2DR B210


 
jel1957 
"5th Year" Gold Supporting Member
Posts: 431

Loc: Sugar Land, Texas
Reg: 01-01-04
08-30-08 06:34 PM - Post#1511499    
    In response to 557B210

how bout an L79 - 327/350 HP. I have the L79 camshaft in my 57 good low end torque, smooth idle.

 
557B210 
Contributor
Posts: 293
557B210
Loc: Jacksonville
Reg: 06-15-08
08-30-08 07:01 PM - Post#1511515    
    In response to jel1957

Okay jel...I could build one of those too, if I wanted to...I have a -151 cam and a set of double camel hump heads....However, MPG is my top priority with this build-up...(think old man, grandpaw, aka POPS)
david aka POPS
55/57 2DR B210


 
MikeB 
Senior Member
Posts: 9475
MikeB
Loc: Plano, TX
Reg: 08-28-03
08-30-08 07:30 PM - Post#1511528    
    In response to 557B210

  • 55B210 delray Said:
Won't I have a problem running regular unleaded with a CR above 9.5 to 1?


With old-tech iron heads and a mild cam? Yes you will! I'd keep at 9:1 or less.
Real Hot Rods have a Clutch!

1955 210 2dr: 327, Brodix IK180 heads, Jones cam, M20, Wilwood front brakes

1982 C-10 SWB pickup, 250 six, 3-speed

My car pictures



 
557B210 
Contributor
Posts: 293
557B210
Loc: Jacksonville
Reg: 06-15-08
08-30-08 08:03 PM - Post#1511544    
    In response to MikeB

Would Vortec heads be my best choice to up the CR and still maintain gas mileage?
david aka POPS
55/57 2DR B210


 
4dr 57 
"6th Year" Silver Supporting Member
Posts: 3335
4dr 57
Loc: The Texas Hill Country
Reg: 11-10-04
08-31-08 04:51 AM - Post#1511642    
    In response to 557B210

Using Vortec heads will allow you to possible use a GM recalibrated Throttle Body type injection system. Save some $$$ and will afford you the low end torque you want.
The trouble is you think you have time - Buddha




 
MikeB 
Senior Member
Posts: 9475
MikeB
Loc: Plano, TX
Reg: 08-28-03
08-31-08 05:26 AM - Post#1511650    
    In response to 557B210

Vortecs are a good choice. They flow extremely well at low-medium valve lift and have a modern, high-swirl chamber that tolerates higher compression.

Just remember you will need center-bolt valve covers and a Vortec-specific intake manifold. And you won't have an oil filler tube on the manifold.
Real Hot Rods have a Clutch!

1955 210 2dr: 327, Brodix IK180 heads, Jones cam, M20, Wilwood front brakes

1982 C-10 SWB pickup, 250 six, 3-speed

My car pictures



Edited by MikeB on 08-31-08 05:29 AM. Reason for edit: No reason given.

 
557B210 
Contributor
Posts: 293
557B210
Loc: Jacksonville
Reg: 06-15-08
08-31-08 06:48 AM - Post#1511665    
    In response to MikeB

One of my main reasons for not wanting to go with the Vortec heads was having to go to a manifold with no filler tube and the centerbolt valve covers....I have a nice old set of Corvette valve covers with no fill/ breather holes that I wanted to use...I was hoping to maintain more of an "old school" look under the hood...I guesss I'd have to make that trade-off to achieve the engine performance characteristics that I desire...Would I be able to use unleaded regular pump gas with these heads?
david aka POPS
55/57 2DR B210


Edited by 55B210 delray on 08-31-08 06:55 AM. Reason for edit: No reason given.

 
Impala65SS 
Valued Contributor
Posts: 3741
Impala65SS
Loc: Sweden
Reg: 08-23-07
08-31-08 08:31 AM - Post#1511698    
    In response to 557B210

I think Summit (and probably all other similar firms) sells adapters for usage between center bolts heads and old style valve covers.
I looked at the aftermarket Vortec aluminum intakes at Summit now, thought first they could be modded to accept the filler tube and a road draft tube... not so. Unless you are willing to cut in to the water cross-over and perform some TIG-welding - still wont look good.
http://www.youtube.com/watch?v=SXn2QVipK2o&a mp;fea...


Edited by Rat The Impaler on 08-31-08 08:57 AM. Reason for edit: No reason given.

 
557B210 
Contributor
Posts: 293
557B210
Loc: Jacksonville
Reg: 06-15-08
08-31-08 11:36 AM - Post#1511788    
    In response to Impala65SS

I guess the only way to provide crankcase ventilation with the Vortec heads and intake manofold on a 60's 327 would be through the valve covers then
david aka POPS
55/57 2DR B210


Edited by 55B210 delray on 08-31-08 11:58 AM. Reason for edit: No reason given.

 
Impala65SS 
Valued Contributor
Posts: 3741
Impala65SS
Loc: Sweden
Reg: 08-23-07
08-31-08 12:03 PM - Post#1511814    
    In response to 557B210

Sorry, with these "new" heads, and all, I'm out of my league... Checking the Summit site was about as much as I can help on the Vortec stuff. The rest would just be total guessing on my part... so I'll shut up for now
I'll be back when we are talking 60-80s parts
http://www.youtube.com/watch?v=SXn2QVipK2o&a mp;fea...


 
5Larry7 
"11th Year" Silver Supporting Member
Posts: 1749
5Larry7
Loc: Dallas, TX
Reg: 05-17-04
08-31-08 12:18 PM - Post#1511827    
    In response to 557B210

Actually the older small journal 327's have a hole in the rear of the block that accepts an adapter (Chevrolet part) that can be hooked to a hose and connected to the base of the carb with a pcv valve. Then to complete the positive crankcase ventillation you run another hose from the air cleaner (inside the element) to a cap on the oil fill tube. GM did it this way until the large journal 350 blocks came out without the hole in the back. In the original 265's and 283's, this hole was hooked to a road draft tube.
'57 210, Blown 327 cid, Holley HP TBI, 700R4, A/C
'51 Studebaker Starlite coupe, 350, TH400, GV OD.
'96 Replica of a 1950's Teardrop Trailer.


 
55 Shaker 
Member
Posts: 1203
55 Shaker
Age: 64
Loc: north central IL.
Reg: 03-13-06
08-31-08 12:39 PM - Post#1511833    
    In response to 5Larry7

My 327 had the hole in the back of the block connected to the air cleaner, and the pcv valve screwed into the oil fill tube, with a vacuum hose hooked to it.
The older I get, the more dangerous, I am !!!!


 
Axelrod 
Senior Member
Posts: 876

Reg: 02-23-04
09-02-08 09:43 AM - Post#1513202    
    In response to 55 Shaker

I built up a 307 that was in my 68 Chevy II Nova back in 1971. With 60K miles, it had flattened out a camshaft and that necessitated a replacement. So with my brother helping me, we changed it to the 350/350 Chevy part numbered hydraulic camshaft, rebuilt the heads, threw on a new Holley 650 double pump, a used Chevy aluminum high rise intake, and a set of used headers. A complete tune and a set up distributor completed the "rebuild".

With the stock 3spd trans and a 3.07 rear end, the car ran consistent mid 14's on street tires at 97-98 mph. It also got decent mileage too. I drove it hard, it felt great and pulled strong. It never broke and I surprised alot of so called factory "muscle cars" with this unlikely combo. I think this car could have easily gotten into the 13's with a decent gear and a 4spd. I have often thought about trying to "recreate" a 307 build, this time with a set of better heads, just to see what one of these little, over squared, truck motors could really do.

 
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