Calling All Experts!

patrickmacintosh · Post by **patrickmacintosh** » May 9, 2007, 9:19 pm

Well fellows I have a situation and I need a real motorhead who can answer a question. I am getting ready to have my 352 rebuilt by a reputable engine builder here in Riverside, Calif (Waynes Engines) I want to squeeze all the gas mileage I can out of it so I plan on installing Doug Thorly Tri-Y headers and a Cam. The cam I chose is p/n EDL-2106 in the Summit Racings catalog. It is a Edelbrock Preformer Cam.

The problem I have is that the so called Tech Experts at Summit say the cam will not work with the stock valve springs and the guy at Waynes Engine builders said there should be no problem since the lift is under .500..So.....who do I believe?

Here are the stats on the cam:

Duration Advertised.
272* Intake/282* Exhaust

Duration @ .050"
194* Intake/204* exhaust

Lift @ Valve
.460" Intake/.480" Exhaust

Lobe Separation Angle...110*

Intake Centerline....105*

Intake Timing @ .050"
Open 8* ATDC
Close 22* ABDC

Exhaust Timing @ .050"
Open 37* BBDC
Close 13* BTDC

If you think the stock springs will not work then can you suggest ones that will. At a later date I may install the Edelbrock Preformer Dual Plane Intake manifold and a 4 barrel carb with small primaries but for a while I will just run the stock 2 barrel, stock intake manifold and Tri-Y headers.

My goal is to acheive the best gas mileage possible. I'm even thinking maybe I will install throttlebody Fuel Injection if I can find one cheap enough.

Thanks Guys!
Patrick
Riverside, Calif
1966 Custom Cab Longbed

jakdad · Post by **jakdad** » May 9, 2007, 10:14 pm

I would go with the engine builders recommendations. You must remember that Summit wants to sell you springs and retainers. The specs on that cam should be fine with stock springs, but I would buy new springs from your engine builder. I wouldn't trust old springs. That cam is not radical and the springs that Summit would sell you would likely spec out very close to the ones you get from your engine builder. And I am no expert but 50 odd years messin' around with these old cars has taught me to rely on good old common sense. Good luck.

bigtrip460 · Post by **bigtrip460** » May 10, 2007, 3:01 am

are they old springs? I think they wear out and dont "spring" as well as they used to.(is it called work hardening?) I would do new just for peace of mind if i was using 30-40 year old springs. but thats me.

66 POJ · Post by **66 POJ** » May 10, 2007, 4:30 am

The builder should test your springs during the rebuild and replace any that are out of spec. The cam in question will work as I have the same one in my FE. Just as long as you stay under .500 lift.

6166 Junkyard Dog · Post by **6166 Junkyard Dog** » May 10, 2007, 7:45 am

if your looking for gas mileage, build a 390 with run stock cam 2 barrell change gear ratio on rear end, I had once a 390 changed to 4 barrell, lost mileage, went from stock cam to a little more bounce lost more mileage then went to little more bounce lost more mileage bottom line took a 23 mpg truck and went down to 14 mpg, 352 motors do not get good mileage cause of the stroke just like it's sister the 360 but take that same truck put 390 in stock and see waht the difference is, if you have not changed the stock rear end ratio at 3:70 or 3:89 then your not going in the right dirrection, changing transmissions unless going to a overdrive

patrickmacintosh · Post by **patrickmacintosh** » May 10, 2007, 11:04 am

Hey Junk Yard Dog.....A couple of years ago a few members posted that they were getting over 20 MPG with their 390's so I was going to trade my 352 for a 390 at the engine rebuilder... UNTIL I read a few members posts about 3 weeks ago saying that 390's were GAS HOGS!
that got about 10-12 MPG

I had a 1972 with a 360 and a 4 sp top loader tranny and the best I got was just under 15 MPG with driving on the open road. That was without dual exhaust so I figured that if I get my 352 bored out .030 over it would be a 357 cu in and if I put on headers, a flex fan and had a RV cam I might get close to 20 MPG which I'd settle for.

If I KNEW with out a shadow of a doubt I could get 20+ MPG with a 390 I would not hesitate to have a 390 put in instead of my original 352.

Edelbrock says that the mild cam I want to install will boost mileage but they can't say how much.

Now I am confused as to which motor to get...!..all 390 owners Please chim in here with the mileage you get and what mods you have on it.

Thanks Guys
Patrick

Johnny Canuck · Post by **Johnny Canuck** » May 10, 2007, 12:15 pm

Patrick some of the things you are doing should help with fuel consumption, and I would try the throttle body injection too.

20 MPG out of an FE tho?
:rotflmao:

the 360 I also had in a '72 F250 with a C6 and a 2 bbl would not have got 10 MPG Imperial rolling downhill in neutral, with a tailwind.

I was dam lucky to squeeze 8 out of it. I constantly was checking that truck for a fuel line leak, I could not believe anything short of a Sherman tank could eat that much gas. :shock:

Best of luck with your project!! Hope you can do it.

bigtrip460 · Post by **bigtrip460** » May 10, 2007, 12:47 pm

try a 460 on for size... i had a 1/4 tank, stopped and put 10 bucks worth of gas in at 2.40 something drove to the store 3 miles away and 3 miles back and had less than an 1/8 when i got back. :roll:

thats driving barely over idle.

but that was the old one that just got replaced. I hope I'll do better with this one.

ELpolacko · Post by **ELpolacko** » May 10, 2007, 1:09 pm

Not that I'm some FE expert, but I do have some tools at my disposal.

Say we build a theoretical 390 on my DynoSim. Standard bore and stroke. Stock heads and valves, good aftermarket intake and a decent flowing set of cast manifolds and a good exhaust system. Set the compression at 8.5:1 and a 600 cfm vacuum secondary carb (for automatic trans).

I would seriously consider spending the extra coin for a hydraulic roller retro-fit kit.

Crane has one

http://store.summitracing.com/partdetai ... toview=sku

This thing is going to give you some real impressive torque nubmers, well over 300 ft/lbs at 2000 rpm and doesnt' drop below that number untill well past 5000 Rpm! Peak torque of 359 at 3500 and peak HP of 308 at 500-5500. VE is real decent too at 81.4%

Most oils are taking the Zinc out of the formulation under decree from the Government. Valvoline VR1 and Shell Rotella T are the only engine oils on the market to currently have Zinc in them. This is what keeps your flat tappet lifters from destroying your cam. More critical for fresh engines and break in but long term the lack of Zinc in your oil will slowly destroy your cam. The aftermarket is already responding by offering more retrofit kits like this one.

Something to consider.

6166 Junkyard Dog · Post by **6166 Junkyard Dog** » May 10, 2007, 3:53 pm

Johnny problem is a 360, 360"s and 352's are gas guzzzzzlers, my 390 in Big Slick gets 15-16 empty when going to slick stock 2006 and look at the size of that truck not just because its a 390 but gear ratio has been changed from 2 speed rear end with 6:33 on the high side to 3:73 single speed, We drove it once with 2 speed rear end sucked some gas now cause difference of RPM'S, Now most 61/66 trucks came 3:70/3:89 or 4:10 some 3:54's that needs to be changed lot of 67-72's F-250 came with 3:73 or 4:10 but few did have 3:54 which where automatics take the low gears out put in higher gear and will see the big difference,, my 66 F-350 Wrecker came with 4:88 thats gone, now has 4:10 and big difference on running and fuel mileage Just remember anybody unless you change gear ratio in rear end no matter what you do to the motor gas might get increased a little but big difference is in rear end or going to next taller size tires will give a little

blackagatha · Post by **blackagatha** » May 10, 2007, 10:39 pm

those numbers for the 390 are pretty decent... not blowing me away, but good. I continuously drool over the prospect of someday having the cash to spice her up a bit (or a bunch).

blackagatha · Post by **blackagatha** » May 10, 2007, 10:42 pm

oh, by the way, polacko... is there any way you could share a copy of the dynosim? I'd love that. If not, don't sweat it.

patrickmacintosh · Post by **patrickmacintosh** » May 10, 2007, 11:28 pm

I checked the link to the roller cam kit and it will not give me any bottom end torque as it says: Basic Operating RPM Range:
2,500-6,000

It is for Drag Strip motors, Not everyday drivers. I'm going to stick with the RV cam from Edelbrock and install new valve springs too, and put on a set of Doug Thorly Try-Y Headers and a flex fan. Then I will check into changing the rear end ratio like many members have sugested.

I will post my mileage after breaking in the motor.
Thanks for all the help and suggestions from eveyone.

Patrick

ELpolacko · Post by **ELpolacko** » May 11, 2007, 12:07 am

Those numbers on Summit are deceptive. The operating range on that cam is from 1800 up. It is considered the economy and towing cam even though they rate it for bracket racing. I really hope to figure out how to export the DynoSim files so you guys could see it. I will run your cam selection and outfit the engine choices as close to yours and compare the two power curves just so you have a frame of reference.

www.cranecams.com

http://www.cranecams.com/?show=browsePa ... e=camshaft

ELpolacko · Post by **ELpolacko** » May 11, 2007, 11:54 am

Here is what I have come up with so far.

[albumimg]1988[/albumimg] [albumimg]1989[/albumimg]

Dyno1 being the Edelbrock flat tappet and Dyno2 being the Crane hydraulic roller. What you can't see is the hydraulic roller is still gaining HP up to 6000 rpm. and the torque isn't dropping off.

I wish I could get the data sheets to copy over, but can't. What they show is while the VE of the EDL may be fractionally higher, its airflow demand is also higher Granted, because VE% is a measure of cylinder filling.

At this point in time Crane is the only game in town for pre-made Hydraulic roller cam conversions for the FE. It isn't a bad choice given thier long term reliability, reduced friction, reduced stress on the valve train and the comming Zinc deficiency in our motor oils. If we were dealing with a Lima series or other newer engine there would be some really choice cams to pick from.

didgeytrucker · Post by **didgeytrucker** » May 11, 2007, 10:56 pm

Back to the original question by patrickmacintosh:

The cam shold give spring specs such as pressure open and pressure closed. Too little pressure will allow the valves to float at high rpm. I doubt you'll see that high rpm. Check your springs against the recommended specs.

If you're going to buy new springs they all probably cost about the same. The lower pressure (stock) springs will require less power to open them and will help you get better mileage.

I believe the smaller 352 would drink less gas then a 390 if mileage is your biggest concern.

So I vote for new stock springs in your 352.

Tracy

patrickmacintosh · Post by **patrickmacintosh** » May 11, 2007, 11:29 pm

Well I was going to have new stock springs installed just to be safe but I found out that if I don't install the Edelbrock springs then they will not warranty the Cam. The springs are only $57 so I'm sure the stock ones can't be too much cheaper.

If anyone knows where I can get a new ring and pinion so I can change the ratio to about 3:07 I'd appreciate knowing. As one member said, the rear end ratio will be the biggest factor in Gas Mileage.

Thanks Again
Patrick

blackagatha · Post by **blackagatha** » May 12, 2007, 2:37 am

I have a 2.73:1 in the back of my truck with the 390, and it drives sweet. A 3.07 even sounds a bit wide for economy. Not bad numbers though, by any means...

As far as springs, new ones are a must. My engine was rebuilt with the old springs. They checked out within tolerances at the shop, but I fear they are the cause of development of my current issues (a definite miss on one cylinder).
And I assume it is probably due to a weak spring, but it's hard telling; when I romp on it, even a long time ago, one of the valves in the right bank would float and pop in the muffler. I assume that was the first indication of my problem cylinder...

Unibodyguy1 · Post by **Unibodyguy1** » May 13, 2007, 1:04 am

Partick,
I have to agree with a lot of the other members on going up to a 390. My Uncle bought 3 new F250 's in 1975. All basicly the same truck. One had a 360 in it, the other 2 were 390s. When the 360 was getting tired several years later, he switched it to a 390, the reason he said was because of "better" gas milage. I used to have another friend of mine here in Las Vegas that had a shortbed 66 that had a 352 2 bll. with a 3 speed with Overdrive. When the 352 was worn out he put in a 390, the truck got something like 3-4 mpg better than with the 352 and it was basicly a stock motor as the 352 with a 2 bll. carb. And my old 71 F100 with 390 C-6 2bbl. and 3:25 gears will consistantly get 14-16 on the highway @ 65 mph. The only things different on it are a 1976 DuraSpark II Ignition and dual exhaust. And also as Tom says tall tires will make a difference too. Just some food for thought.

Michael

Calling All Experts!

Calling All Experts!

Gas Mileage

Roller Cam?

Stock Springs VS Edelbrock Springs

Calling All Experts.