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Discussion Starter #1
I’m updating a way old post regarding an old 393W build post. After helping building it, putting it in the car, and taking it to the drag strip, we were a little disappointed. It only ran a best of 11.79 at 114 MPH. On paper, we thought it would at least run mid-to-low elevens. He is the set up;

• 393W; 850 Quick Fuel carb, Victor Jr & one-inch open spacer, .030 flat top 10.6 to 1 (cranking compression is 170 PSI), World Products Sr with moderate porting for the 2.02/1.60 valves, Lunati solid roller 253*/256* @ .050”, .621” in/ex on a 108* lobe separation +4*, 1 7/8” x 3 ½” headers with 18” collectors, deep oil pan modified with a windage screen, and a complete -8 AN fuel system & pump with a -10 AN pickup,
• The 351W it replaced used the same components as listed above and ran 12.09. Again, it too should have run quicker.
• ‘69 Cougar with roll bar and sub-frame connectors
• Car & driver 3300 lbs
• 4000’ish stall in a C-4 with a manual valve body
• 28 x 9 slicks
• 4.30 rear ratio
• Car launches well, pulls the tires off the ground, shifts at about 6300 and pulls through the traps at about 6200. This is a drag strip only car and I’m sure it has the potential to go faster. It has no hic-ups, surging or anything; it runs great! What are we missing?
 

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Looks like a decent combo..Were the heads done by a reputable shop that knew what they were doing? What mph did the old 351 run? Were the heads ported on the 351 combo?
 

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It does look like a nice combo that should run better. The work on the heads is a concern. Heads can make or break a build.

I feel that with that cam you are not spinning the motor high enough and are just barely getting into its power band.

Full incrementals of the run (and a video might be helpful.)
 

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If the heads were decently done the intake is the cork. i DOUBT IT FLOWS MUCH MORE THAN 190ISH cfm bolted to a good head.
Do those heads have a raised intake port location. Torker IIs are the wildest intake Edelbrock makes that retains the stock port location well almost. Have measured up a few that are off a bit but possibly just due to tolerance stack ups all gone to the extreme.
 

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If the heads were decently done the intake is the cork. i DOUBT IT FLOWS MUCH MORE THAN 190ISH cfm bolted to a good head.
Do those heads have a raised intake port location. Torker IIs are the wildest intake Edelbrock makes that retains the stock port location well almost. Have measured up a few that are off a bit but possibly just due to tolerance stack ups all gone to the extreme.
The Torker II intake is a low profile single plane intake that will not make the power the Victor JR will. And yes I have actually used that intake. It is not a good choice for drag racing unless hood clearance is a concern.
 

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If the heads were decently done the intake is the cork.
I respect your opinion but by experience shows that the stock 351w Vic Jr is not (yet) a cork on that motor, which is quite similar to my old 393w build. My race weight is a couple of hundred pounds more. I also used a smaller carb and smaller diameter headers.

First rendition of my 393w was Vic Jr, Pro Comp 210 heads, 10.5 compression and it ran 11.70'[email protected] with 4.11 gears.

I then installed out of the box AFR 205 heads. Ran 11.20'[email protected] with the same basic combo and 6600rpm shifts. That is why I would love to see a time slip.

I've also ran the same Vic Jr on my current 10.7 compression 428w and it has taken me well into the 10's with the same AFR heads, carb and headers. Gear has been swapped for a 4.33. Basically everything attached to the block was a cork-but it still performs adequately pushing the heavy turd.

This year I swapped out the Vic Jr on this motor for an out of the box Super Vic and there wasn't a noticeable difference in performance, even after tuning and trying a 1/2" spacer. Actually my best time is from last year with the Vic Jr.

We need to see more of what is going on during a run and his combo begs to be shifted higher, IMHO.
 

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Excuse me I meant a VrJr. As for a Senior as far as I KNOW THEY are a raised port configuration (never had a chance to measure one up) not a stock port location. Heads up on flow testing both the TorqerII AND the VrJr they both flowed about the same. I flow tested them both on ported DOOE heads flowing 235 CFM at .500 lift and a Canfield head flowing 320 CFM at .500 lift.
 

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Turbo if the vic jr intake was such a cork there wouldn't be much point in running aftermarket heads. As has been established by many an out of the box vic jr works just fine. I just ran 123mph with mine on the weekend.

Like Dennis said a timeslip might help narrow down where the problem is but your mph is definitely low. I would expect your mph to be somewhere in the high teens or around 120 mph. I don't have any experience with those heads but doing a quick google there seems to be a bit of a love/hate relationship with them. There are some pretty quick cars running them though but usually with some work done to them.
 

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The 351W it replaced used the same components as listed above and ran 12.09. Again, it too should have run quicker. What are we missing?
A set of these . . intake 315 exhaust 235 @ .650 with only 195 cc runners with small diameter valve springs

Air Flow Research

or these

intake 321 exhaust 227 @ .600 with a 205 cc runner with small diameter valve springs

Trick Flow® Twisted Wedge® 11R 205 Cylinder Heads for Small Block Ford TFS-52616601-C03 - TrickFlow.com


In stock form, the Windsor Seniors flow around in 240 ex 150 . . I know yours have had some work done but just how much? . . In addition to the intake flow, the exhaust flow on those heads kinda sucks and has a poor ratio to the intake of around 66% . . The AFR's have an ex to in ratio of around 74 and the Trick flows are around 70% . . I think a custom cam would work better than that Lunati with those heads . . I would give Chris Straub a call [don't email] and see what he says . . He is one of the top cam grinders in the Country.

http://www.straubtechnologies.com/

I know this doesn't directly answer your question buy it's all I got for now.
 

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Discussion Starter #11
The heads were not "worked" but cleaned up and the exhaust was polished to a mirror finish. These heads when on the 351W went 12.09 @ 109, but did rev higher (6700). Again, everything was the same with the exception of the CID.

60' - 1.683
330 - 4.833
1/8 - 7.497
1/8 MPH - 91.59
1000' - 9.817
1/4 - 11.790
MPH - 114

On the return trip home from the track, I realized I forgot to bring a vacuum gauge to check top-end vacuum pull.

It runs well, it seems like it doesn't have the pull that it should.
 

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Here is a timeslip from last year for my combo. My car is a 4 speed manual so it is a little slower than a comparable combo with a good working auto trans (at least with me shifting). It is very similar for the first half but my combo is much faster (mph) through the second half. I am running vic jr cylinder heads and a camshaft with similar intake duration but more exhaust duration,lift and a wider lobe separation. I run a 4.11 gear with 26 inch tall tires. Is it possible that you are running out of fuel on the top end?
60ft......1.68
330......4.88
1/8th....7.50
mph.....93.8
1000....9.73
1/4......11.59
MPh.....120.32
 

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I don't doubt that the MPH would be a little lower in a auto vs stick car. Maybe in the order of 2-3mph?

Fuel is a good place to look--hook up a pressure gauge and see what its doing when the motor is pulling. Might make sure the throttle blades open all the way when the pedal is pushed (verify.) Mess with the timing a couple of degrees each way at the track to see how the motor responds. Perhaps the converter is not up to snuff and is robbing more power than it should?

But then again, it could just be that the motor is not capable of making more steam. Although the heads may have been fine for the 351w, for the the big block bore of the 393w they are not adequate to increase performance to the levels that you are looking for. Big block cubes need to be properly fed in order to perform.
 

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Discussion Starter #17
There is a fuel pressure gauge that remained constant at 6 -7 PSI during the entire pass and the throttle plates do open fully.

I think I may have answered my own question by stating it rev'ed higher and with no problems when they were on the 351W and with same with the cam. I'm now wondering if the heads and/or cam may not flow/big enough. But, it that is the case, it should have far more bottom end and then die off as the RPMs increase. I'm still hoping for a relatively inexpensive solution.
 

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I'm still hoping for a relatively inexpensive solution.
a custom cam as i mentioned.

did you set the timing curve so it is optimal for this setup.

you can plug the vacuum advance if you have one then rev the engine to between 1/3rd and 1/2 throttle, then advance the timing 4 degrees and if the rpm increases noticeably and it still runs smooth, this is closer to where it wants to be.

leave the vac adv plugged and test drive it and listen for it to ping when you accelerate.

jetting may also help.
.
 

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Discussion Starter #19
On a whim, I contacted Comp Cams for a possible cam recommendation. Needless to say, I was a bit shocked when they recommended we switch to the XR286R, but with a 108* lobe separation instead of the off-the-shelf 110*. Seems a little shorter than what I have, but they also knew the specs of what is currently being used. If anything, I thought the recommendation would go the other way and be a bit larger.
 

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I just looked over your build again, the one thing I need to clarify is are you advancing your cam 4 degrees now?

If true this will kill power over 5500 or so, with 4000 rpm stall, 4.30 gears and 393 cid. you don't need the lower rpm help that advancing the cam does and 4 degrees on a 108 CL seems like a lot.

Over 5000 rpm is were your combination spends most of time so before making a cam change I would put your cam strait up and go from there.
 
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