Technical thoughts on 327 camshaft for improved economy

I know there are about million threads out there, and I have been reading them, but here goes anways. I live in the middle of nowhere, and am being forced farther from civilization, but am not willing to give up on my 59 ElCamino. I have a 62 327 with double hump heads(461s) .060 over with flat top pistons, 2 inch rams horns, a Saginaw 4 speed and 3.55 gears. I am going to install my 3 rochesters, and 3.08 gears. I am looking at an isky 262 mega cam ,
https://www.summitracing.com/parts/isk-cl311256-262/overview/,
but am worried I may have to much compression for this cam, (108 LSA). I had good results with a low compression 350 years ago in my 66 c10 and would like to get at least to the mid teens mileage wise. Thoughts, comments

 

Eric
I can honestly say I've never considered your proposal, happy for you if you achieve your goal though.
Praise the 327!

 

have you thought about turning your Saginaw into an overdrive using the back of a 3spd o/d unit?

 

There was a common build for daily drivers back in the 80s. Take a 350, freshen it up with rings, bearings, etc (overhaul kit). Then add an RV cam, Edelbrock single 4 barrel intake with Quadrajet, headers and duals. Gave an extra 30 or 40 HP over stock, and a few more miles per gallon. No doubt the same parts will work on your 327. Maybe there is a more modern version of this build, any Chevy guys have a suggestion?

 

Smaller motors like smaller cams for gas mileage.

I like a 250*-260* X-treem Energy Comp Cam, (which has 110* LSA) for gas mileage. I had one in the car in my avatar with small valve iron heads and flat tops in a 383 and it got 22 mpg. Oh, I have a 144 B&M blower with a 750 cfm Edelbrock on it too, pushing only about 4# of boost at full throttle.

I know it was under cammed for the application, but it worked.

Also, I run a T5 and a 9" with 3:25 gears and 29" tires. It turns 1950 rpm @ 60 mph.

 

Never really thought about detuning a 327. Most questions are for more performance.

 

4x4 cam, about 250º advertised, narrow LSA. Block the outboard two carburetors, and run on just the middle one.

 

Don't think detuning, just changing the performance parameters.

 

My '72 camino 350, camel humps, flat top pistons, 151 cam and a four barrel, got 24 MPG every day. That's Canadian gallons, about 20 on your itty bitty ones, Haha

 

This is more or less what I had in the early 90s. dished piston big chamber head 350. The part throwing me a curve on the 327 ,is the flat top pistons, and 64 cc heads, and the 108 LSA. I don't want to have to run premium fuel.

 

what carburetor?

 

As an option outside, wondered what a bedcover and rear skirts would do. (No, Marty S., I didn't mention a belly pan!)

 

Sounds like a healthy 327, I really like those early El Camino's. Be a shame to gut it for a few more MPGs. I think I'd be looking at gearing, trans, or O/D options, rather than muck with an engine combination the you're happy with. Running the center trip only with a cam change, might help some, as someone suggested. Hard to have your cake & eat it too....

 

Performance tuning is probably "easier" than tuning for range or economy.

 

My coupe has a SBC much like yours......last summer I pulled the Edelbrock 650 and put the quadrajet back on. Instantly gained 6-8 mpg with no other changes.

 

The best cam for mileage is to buy the biggest one you can find and put it under the gas pedal.

 

Big change! How bad was it with the 650, and tell us about the rest of your combination.

 

The old RV grinds were a balance between fuel economy and towing power. May be worth a look. I like the Quadrajet idea myself.

 

With the 650 it got 12-14 normal highway driving, now getting about 20. I don't drive like an idiot so much anymore, so I really didn't notice much change in performance. Q jets are great carbs if set up properly.
Engine is a 350 with flat tops, z28 type cam(can't remember exact specs) 1.94 heads, 3 spd manual and 3.55 gears

 

With progressive linkage and a fairly mild cam from Comp Cams, you ought to get good mileage and have better than stock performance by a good margin. Remember that you are quite a bit lower in compression than Chevrolet advertised. The pistons set down farther and the heads are larger than blueprint specs.
Pete

 

Through the decades I have run 327s in several Corvettes. One had the Chev 300hp cam and one had the 350hp cam, power band a little higher in the rev range on the 350hp. I never thought to check the mpg because the cost per gallon was way south of a dollar.Those were great all round cams with lots of fun factor. Presently I am running a Comp 268 in the 350 in my '40 coupe. Performance is great also but my gut is that the previous combo's produced better mpg. Maybe it is the huge difference in cost per gallon that skews the perception but it seems like I am always putting gas in the '40 as opposed to rear tires on the vettes. Tri-power on all three. Keep track of your timing and the vacuum going to your advance as you change carbs and intakes. Good luck.

 

With a 4" bore and 64cc heads you won't have too much compression. You should be about 9.8:1.

 

Take the money and time to change the car and buy a cheap truck or eco- box. Or sell me that el cam.


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I know this might sound stupid. But why not call the tech line at whatever cam company your considering. Thats what there job is.

 

Before you jump at camshafts-by-catalog and installing that tri-power....

1. What camshaft is in it now?
2. Do you happen to have a factory AFB and intake manifold?
3. I would highly suggest having a discussion with Jon of the Carb Shop (HAMB name Carb King) his knowledge is incredible and I believe that he would steer you in the right direction.

Personally, I use Q-Jets because I have had all the others and they never produced the results as the Q-Jet will.
You really need to find a model number that is as close to your original engine combination if possible, or if your comfortable in modifying and tuning as I do, you can get there.
I went from 10-12 MPG running a Holley 650 or a Demon 650 to a factory intake manifold and my own "Blueprinted/modified" Q-Jet and get 20+ MPG in my Coupe. It's a Chevy 357, 9-1 compression, hyd. roller, Dart heads, headers, Turbo 400, 3.55 rear gears with 27" tall tires.

 

This may help but in a different direction. Which Saginaw do you have? There were 3 different first gear ratios available, 2.54, 3.11, and 3.50. If you currently have a 2.54 version with 3.55's you currently have 9.017 first gear multiplication. A 3.11 version with 3.08's would be 9.57 in first, an improvement for first gear. Online RPM calculators show 70 MPH with 3.55's and a 28" tire at 2982, same parameters with 3.08's, 2587. Almost a 15% drop, not as great as OD. but an improvement never less.

 

Wife's 55 that she drove for many years commuting on 101 (still have) has a 327 flattops, 461's with 1:94/1:60-changed exhaust size, a factory 350HP aluminum intake, a factory AFB with a Sig Erson TQ 2Q cam (basically an RV cam) and a powerglide with 3;36 gears. Was our main car for many years and was good for 20-21 MPG on the road-sometimes a bit more with her driving on long trips. I changed cams in it several times to see the difference-comp 260 was about the same-268 was less mileage. Changed the rear gears to 3:55's before a trip of 1500 miles and did'nt see any change in mileage. We drove this car on many long trips on a regular basis. My 40 has a similar motor with a Crane 266/440 cam, an AFB, turbo 350, 3:00 gears-20+ on the road.
I'm no expert but have since built 2 40's with 327's like the one in wife's 55 but with Crane 266/440 cams and same drivetrain as my 40-they also get decent mileage if you keep your foot out of it. Seems 327's have a sweet spot about 2500-2700 rpms-just my experience.

 

Ol Scrounger, you are one silver tongued devil

 

I just can't help myself, what can I say, 327's just bring out something in me!

 

Yeah, but those are metric miles, too.