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Discussion Starter · #1 ·
Hello all, new to the board here and have some questions I am trying to get answered. I recently had the 289 in my 66 convertible rebuilt and its not running like I thought it would. I it was put together with the stock crank and connecting rods, bored .020 over, and tightened down with ARP bolts for a solid lower end. I installed an Edelbrock performer power package for the top end. Performer Alum. heads with 1.90 intake valves, performer intake, performer 2122 cam, and performer 500 cfm carb. I used the stock distributor with a Pertronix ignitor. I am running this with JBA shorty headers and dual exhuast with an H pipe. I was hoping to get a little more power out of it and ok gas milage since its more of a daily driver. The engine now has about 400 miles on it and its quite the opposite of what I thought it would be. It has less power than the stock motor, gets 10 mpg, and it signs off aceleration wise at about 4000 rpm.
My questions are this, the Edelbrock heads have bigger CC compustion chambers by 5cc's. Could that have dropped my compression ratio in the garbage? would I have been better off with a stock cam for milage? Would it be better to go back to the stock heads or have my Performers milled down to get the compression up. I am thinking of going with milled Performer heads, stock cam, and the rest of the set up I already have. What ever I do, I only wanna do it once to fix this problem, so any advice would be awesome.

Thanks.......
 

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Hello Oakes66,
Welcome to the forums.
First don't be too quick to make changes.
I am a backyard mechanic but what you have sounds good. The only problem I can see is the carb mat be too small.
Is the motor fully properly tuned?
Perhaps a bit off timming or carb adjustments?
Also check for vac leaks etc.

I don't think you need to do a lot. I would advise at least a 600 - 650cfm for the motor.

Others will help but the car sounds like it is not running like it should.
Check and recheck all simple things first.
Spray carb cleaner at the carb base and around the intake to check for leaks. Look for vac lines left off.
You spent the money already don't be discouraged yet.......Jim
 

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Discussion Starter · #3 ·
I think I have gone over this with a fine tooth comb as far as little stuff. The timing is set at 10 btdc, and vac advance is working. No apparent vac leaks. Edelbrocks tech line rep says that I may have to high of fuel pressure. Sounds silly to me but I will be checking that tomorrow as well as intake vacum. I was going for decent fuel milage, hence the 500 carb. Another question i have is about the coil. I bought a stock replacement coil off of Ebay and I am running the plugs at .032 as stock recomends.
 

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Hello Oakes66,
Plugs could cause a problem. Perhaps you need a hoter plug or a different
length plug for the heads. As I said I am just an old backyard mechanic.
Perhaps the makers of the heads could suggest a plug.

I am sure there will be lots of replies in the morning from others who may be far more able to help.

My main issue is that you shouldn't get discouraged because there could be a simple fix. What you have should give you a good kick in the pants when accelerating and pretty good mileage.
As far as acceleration dropping off at 4000, I think you could be starving for fuel. I agree if you are running a stock fuel pump, the carb should handle it firn. If running an electric pump perhaps a fuel pressure reg would help. I don't think this is the issue however.

You'll see you will h=get it going without spending much money.
Wait for others to reply and they will..........I wish I could help more.....Jim
 

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Looking at the Edelbrock website you have the #60329 heads (60cc) and 2122 cam
#2122

ENGINE: FORD 289-302 V8
RPM RANGE: 1500-5500

Duration at 0.006" Lift:Intake: 270°Exhaust: 280°Duration at 0.050" Lift:Intake: 204°Exhaust: 214°Lift at Cam:Intake: 0.280"Exhaust: 0.295"Lift at Valve:Intake: 0.448"Exhaust: 0.472"Timing at 0.050" lift:OpenCloseIntake:5° ATDC29° ABDCExhaust:44° BBDC10° BTDCCenterlines:Lobe Separation - 112°Intake Centerline - 107°

Just want to make sure we have all the numbers right.
Do you know what part # / model pistons were put in? dished, flat top, domed, and any other info on the pistons?

That should be a nice setup and you should get better mileage than stock since the motor breathes better and would be more efficient. Something is holding you back as your cam should climb to 5500RPM's before tapering off at all if then even.
Jon
 

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Discussion Starter · #6 ·
The above post is correct, that is the set up I am running. The pistons are forged flat top pistons with small relief cuts made for the valves. I am not sure of model number, but they are stamped 0.020 for the bore. Used a fel-pro Head gasket and intake gasket. I agree that it should get good mileage. I thought I covered all my bases when I chose parts and did not get a crazy cam or anything, and went with the smaller carb. The carb was on the 289 prior to the rebuild as well as the distributor. Everything else is brand new including a 3 row radiator for heat, and I have a T5 tranny. I cant for the life of me figure out why this thing wont get at least 15-16 mpg. As I said before, the Edelbrock rep says that I need to check my fuel pump pressure as that could be causing bad mileage and poor performance. The pump to is a new stock replacement. I have been told that the carb may be to small, but the Edelbrock data sheet says I can use the 500cfm. Once again, any thoughts. Could any of this have to do with how new the engine is, spark plug gap, underpowered coil.....I am grasping at straws here to avoid ripping this engine apart again.
 

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I think that you might give the engine a little more break in time. The internals may still be a little on the tight side and the rings not completely seated. The 500 CFM carb is more than sufficient for a small displacement engine such as your 289.

I really think that you need to check the timing advance and then the carb jetting. Leave the plug gap at the stock setting. Opening the gap will stress your stock coil and ignition wires, trying to overcome the increased gap.

The base timing of 10 BTC is a good starting point. The centrifical advance should be all in by 3000-3200 RPM with a manual trans. The automatics like it all in a bit sooner. You don't want to exceed a total of base and centrifical timing beyond 38 degrees at 3000-3200 RPM and above. I prefer to be slightly conservative with a total of 36 degrees. The vacuum advance doesn't enter the equation above and should be disconnected and the vacuum source plugged when plotting the advance curve.

I personally prefer to use the vacuum advance hooked up to full manifold vacuum. Others don't and use the timed source off of the carb, where the vac. advance doesn't come into use until the throttle is opened. I'd try both ways and use what is best for your combination. Regardless of the hook up method, the vacuum advance shouldn't allow for a total timing to exceed 52 degrees BTC. This is the sum of total timing, base, centrifical and vac. advance.

You should get the ignition portion set before going to tuning the carb., unless something is obviously wrong with the fuel system. It may be possible that you have insufficient fuel delivery beyond 4000 RPM and this is contributing to the engine laying over too soon. Something as simple as a clogged filter screen, (Sock), at the fuel pick up inside the fuel tank can be part of the problem.

I wouldn't start tearing down the engine as I don't think that there's a problem with the assembly or with the type of components used. The engine's fuel and ignition systems need to sorted out. I'm suspicious with the set up of the stock distributor, though. The advance rate and/or advance mechanism may need attention.

One more thing that hasn't been mentioned that can contribute to the engine laying over at speed is a restricted exhaust system.
 

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My questions are this, the Edelbrock heads have bigger CC compustion chambers by 5cc's. Could that have dropped my compression ratio in the garbage?
Yes, your compression ratio would have been better with stock Ford heads. For '66 they were nominally 54 cc and adding 6cc to that would drop the CR by about 1/3 of a point to nominally 9.0:1. 289 heads were always 55cc or less until '68 when they dropped the 289 CR to 8.7:1.
 

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Discussion Starter · #9 ·
Yes, your compression ratio would have been better with stock Ford heads. For '66 they were nominally 54 cc and adding 6cc to that would drop the CR by about 1/3 of a point to nominally 9.0:1. 289 heads were always 55cc or less until '68 when they dropped the 289 CR to 8.7:1.

Would this drop in compression cause such a loss of power and mileage. could i remove just the heads and ave them milled down enough to get me in the 9.5 to 10.1 range, thus increasing power. And could tis be done without milling the intake.
 

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Would this drop in compression cause such a loss of power and mileage.
I wouldn't think so. The low MPG sounds more like a carb problem to me. You don't want to go too high in CR: with 10:1 it will be hard to find high enough octane gas. I rebuilt mine to 9.5:1 and expect to need premium at sea level.
 

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I have a similar setup on my 289, I used AFR-165s, Wieand Stealth intake, Speed Demon 575 carb mech, comp xe262 cam, Hooker Comps, Magnaflow 2 1/2 inch exhaust, also with a T5. I was getting 20MPG which was less than I expected ( I made minor tweeks to a setup that was getting me 28MPG). I took the car to a shop to put on a dyno. Found that at highway cruise I was running way too rich, 12:1 AFR. I expect that when I finish tuning things I'll be back into the mid 20s MPG. As things were, I did 291RWHP and 300ftlbs.
 

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Discussion Starter · #12 ·
Do you know what size cc chambers your AFR heads have. I know that the Edelbrock heads flow a little less than the AFR heads, but Im going daily driver. I am also considering that same xe262 cam. After reading many posts I am finding people are very unhappy with the performer cam. I am going hunting for problems in the morning. I am gonna check the fuel PSI and Vacum at manifold. I will follow that up with a compression test. Does anyonr know if 300 miles on a new motor is enough time to do an acurate compression test. And It is stll unanswered if a weak coil could be causing it to run good enough to drive, but still get bad milage.........
 

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Does anyonr know if 300 miles on a new motor is enough time to do an acurate compression test. And It is stll unanswered if a weak coil could be causing it to run good enough to drive, but still get bad milage.........
Depends. What kind of rings did you use? If they were moly then they were seated about 299 miles ago. If they were chrome they may not seat for another 1000. Actually there really isn't an 'accurate' compression test. The accurate way to do this is do a leak down test. Compression tests have too many uncontrolled variables to be 'accurate'. They are a first check before you do a leak down.

I really doubt the 'marginal but drivable' coil theory. If its that bad it won't run right. A spark plug only starts the burn; the fuel burns by itself. If its firing correctly then it should be burning correctly. An overly rich mixture will do exactly what you report.
 

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The AFR-165s are 58cc

Joel

Do you know what size cc chambers your AFR heads have. I know that the Edelbrock heads flow a little less than the AFR heads, but Im going daily driver. I am also considering that same xe262 cam. After reading many posts I am finding people are very unhappy with the performer cam. I am going hunting for problems in the morning. I am gonna check the fuel PSI and Vacum at manifold. I will follow that up with a compression test. Does anyonr know if 300 miles on a new motor is enough time to do an acurate compression test. And It is stll unanswered if a weak coil could be causing it to run good enough to drive, but still get bad milage.........
 
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