Car slower with CNC ported heads?

MEV

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I was not able to have the block line honed on the original rebuild due to a lack of that service around my area. When the heads were off, I had the time to drive the block to a machinist 150 miles away and have it honed.

The cam was installed "straight up" per comps recommendation, I did not advance or retard it, save for whatever comp ground into the cam when it was manufactured.
 

1978 NYB

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Have you had it back to the track yet?

If so....ET and MPH results change any?
 

twostick

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I was not able to have the block line honed on the original rebuild due to a lack of that service around my area. When the heads were off, I had the time to drive the block to a machinist 150 miles away and have it honed.

The cam was installed "straight up" per comps recommendation, I did not advance or retard it, save for whatever comp ground into the cam when it was manufactured.

Degreed in with a wheel or dot to dot on the gears?

Not sure why if it was good enough to assemble before, you would have it done after. BB Mopar mains don't usually need to be messed with.

Kevin
 

1978 NYB

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Yes, the results are in the 1st post in this thread.

I meant since then.

Atmospheric conditions can greatly affect performance in naturally aspirated engines. I would try several test days to determine what the true performance is after the head work.
 

pomonamissel

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port wind speed is very important at lower rpms , you are down there on the flow numbers . but fresh parts need to bed in and get loose . should get faster the warmer it gets . does it launch as hard to you ? are use running old tires , they can harden up , lose there bit .
 

MEV

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The tires are fresh. The car launches harder but I noticed it spins more off the line than it did. I think the spinning and the trans has more to do with it than the motor. I have a TF-2 transgo shift kit on the way.

Here are a couple of the passes last year when it when 12.80.
 

70bigblockdodge

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I'm going to assume it is still a full automatic. Did the kickdown linkage get out of wack when engine was out? Sounds like it's adjustment might have been wrong or was binding and you made a couple of passes in a powerful car that may have fatality toasted your clutches. Just thinking aloud. Wheel spin should not be a factor with a car with drag radials tall gears and that much ass.
 

MEV

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UPDATE/UPDATE Got the trans back in finally, and went to the track last night in the 100+ degree heat. As always I drive 70 miles, swap to the drag radials and get in line.

The first 2 runs the car vapor locked at 2/3 track.

I let the car sit for 3 hours with the hood up till I could touch the manifold and radiator without discomfort.


Car went:

12.67 @ 105.9 MPH
60 foot 1.725

I still think the car should be faster with the CNC'd heads. The plugs show it to be a bit rich, but i am ok with that for now. I set the cal-tracs at 1/4 turn of preload. I did fab and install sub-frame connectors since the last time I was at the track.
 

bajajoaquin

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Any update here? I am amazed you're running in the 12s with only 230 degrees of duration and 3.23s. That's totally streetable.

I've thought about the same Stealth/505 combo but a hydraulic roller in the 218-220 duration range.

Your vid is currently my favorite on YouTube. Probably 50 of your views are me watching you smoke (literally) that 5.slow
 

MEV

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Any update here? I am amazed you're running in the 12s with only 230 degrees of duration and 3.23s. That's totally streetable.

I've thought about the same Stealth/505 combo but a hydraulic roller in the 218-220 duration range.

Your vid is currently my favorite on YouTube. Probably 50 of your views are me watching you smoke (literally) that 5.slow

I went 12.67@106 with a 1.72 60' time on a 105 degree day with 135 degree track temp at 3'. The trans was holding on the the shifts about a half second too long. I am sure there is more in it, my goal is 11.99's I am going back to the track in a month when its cooler.
 

330dTA

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I went 12.67@106 with a 1.72 60' time on a 105 degree day with 135 degree track temp at 3'. The trans was holding on the the shifts about a half second too long. I am sure there is more in it, my goal is 11.99's I am going back to the track in a month when its cooler.

I really like your video. The car hooks up real nice and stable. Would you care to share what you've done to it besides the engine and tranny?

Modifications to the rear axle?
 

MEV

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I really like your video. The car hooks up real nice and stable. Would you care to share what you've done to it besides the engine and tranny?

Modifications to the rear axle?

These are the only things i have changed on the car in addition to the engine.

Added scarebird disc brake conversion on the front

2" lowering blocks in the back, backed off the torsion bars in the front to lower it a bit,
and added cal-trac bars to the rear.

The rear axle is the original 489 case with detroit locker and 3:23 gears, I swapped out the original bearings for the green bearings.
 
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