New track times for my '66 Coupe

[Vinyl66]

I went to Atlanta Dragway last night for test and tune to try to improve on my 12.44 I ran last month. My 60 foot time on that run was a 1.95. So traction was the first order of business. Since then I installed some slide-a-link bars so last night was the first time I tried them.

First (and best) run of the night looked like this:

60'...1.756
330...4.963
1/8...7.686
MPH...89.81
1000...10.075
1/4...12.128
MPH...109.18

My little 215/60 14 BFG drag radials stuck pretty well on this run. I spun on my other runs and had some 1.8x 60 footers.
Traction is now halfway decent for the small rubber I have but what I need to figure out now is why is my mph not better. No matter how I launched or what rpm I shifted at my 1/8 was 89.8-89.9mph and my quarter was 109.1-109.5mph.

:Carb is a 650 vac. secondary Demon. Could be slowing me down or not. I did pick up 2mph just by raising floats last month. Have not even messed with jetting.
rofessional Products Air Gap manifold. I doubt it flows as well as my stock AFR185 heads. I am guessing it is a bottleneck. I picked up a used Vic Jr to try out sometime. (Washmo66 recommends it and his car is FAST)
:Stock 5/16" fuel line and stock mechanical fuel pump. This is probably what I should fix first.

 

[57fairlane]

Sounds like really good times to me. What cam is in it?

And whats with going to atlanta dragway and not telling me?!?

I need to go to the track.

 

[302 coupe]

mph won't go up unless you add power or remove weight. 60ft times have very very little effect on mph.
Those some good times, and it looks like the the slide-a-links are working well.

 

[Vinyl66]

57Fairlane:
The cam is a Comp XE274H flat tappet with 230/236 duration at .050".
You should come out there and race next time. It was crowded but great. I will probably be going back out next month some time.

302 Coupe:
I think some part of my combination is is a bottleneck keeping the MPH low. Most other cars running high 12's and low 13's had more mph than me. Of course I wouldn't trade a second of et for a few mph but it just got me thinking. It feels like it has TONS of low and mid range torque and horsepower but just seems to hit a wall near the top end of the track. Although I am gaining 20 mph from 1/8 to 1/4 which is normal I think.

The slide-a-link bars are definitely working! I am very happy with them. They hit the tires pretty darn hard. On my best run I still feathered the throttle a bit on launch. All my other runs I tried to come out too hard and spun the tires.

 

[10secgoal]

Jet it up. I had the same prolem with mine. Low MPH but it hooked like a champ. I jetted up 5 eventually by the days end and gained 3.5 mph in the middle of the day. I kept going up and went from 12.4 at 104 to a few weeks later running 12.1 @109.9 with a 302 in a 67. You have the same heads I do, and a bigger motor. You do the math, it's got a ton more. I think your biggest problem is the vac secondary carb.

 

[57fairlane]

At some point you have to figure out how far down the race car path you plan on heading.

I was at the same point, debating on ditching the air-gap and going to a victor jr/#4777 with a chokeless main body. But is it worth the $700 to get 20 rwhp? I ain't worried about it . . .

But I do need to get to the track bad. I live about 30 minutes from the old dallas/southeastern dragway and I am trying to get up to calhoun to check it out. But I would love to see what it does in the 1/4.

 

[Vinyl66]

10secgoal:
That is a HUGE increase in mph (power) from just jetting. That is great to know. I think the 650VS is keeping me from realizing its full potential as well. I will try stepping up the jets now especially considering that you picked up so much. That's much cheaper than a new carb right now on my frugle budget.

57fairlane:
My carb has an electric choke so I was wondering how much it would help to get rid of the choke and choke horn. I don't really need one here in GA. Swapping a chokeless main body would be easy but it would also cost more

 

[washMO66]

What RPM are you going through the traps at? The reason I ask is that you have 3:55 gears and my coupe with 3:73 was only hitting around 6K RPM going through the traps with a 26" tall slick. (119MPH).

That was with the XE274HR CAM which is good to 6200RPM whereas my new cam is the XE286HR which should spin to 6600 and the power band should have moved up a little. I haven't had the new combo at the track yet (new cam and went from 2500 stall to 3500 stall + brake) so I am not sure what it will do yet. I may need more gear, we'll see... I plan to get my new cage done sometime in late June so I should have new #'s following that in July....

Also, not sure that fattening it up with jets will improve anything, leaner is meaner and if your mixture right now is not too lean I see no reason to change jets, err to the rich side but don't overdo it

I'm a broken record I know but when I had a pro-products dual plane on my car it did not run anything like it does with the Vic Jr. If you are interested in a few weeks I will sell you my mighty demon 650 Mech sec carb as I am going to change mine out to a MD 750 mech sec. I also know someone with a polished pro products Vic Jr. clone that may be for sale. I borrowed the 750 from a buddy last year and it netted me almost 2 tenths over the 650..... Not saying you should move up as my heads have had extensive surgery on them to breath better, the 650 on my car is very very crisp but I'll trade some of that for a little more up top.

Sounds like your running strong,,,

 

[Vinyl66]

washmo:
I cross the line at about 58-5900. It is difficult to tell on my small tach but that is close. My current tires are 24" tall. I have read that I should be 4-500 rpm over where the cam makes power for the best et. That would put me crossing the line in the 6500 area. I know some steeper gears would help.
I also need a bit more tire. Maybe a 26 x 9 or so. (that would further reduce my gearing.) But I want an 11 on these little tires first

I have read lots of threads here and elswhere about people picking up LOTS of power using a Vic Jr intake on their 347's. I picked up a used one cheap enough and it is sitting in the garage ready for my next oil change to give it a try. I have also read about people picking up some time with double pumpers over VS carbs. Does gas mileage really suffer? Not that my mileage is good now but it really doesn't need to be much worse.

I can't wait to see your times once you get your car back to the track. A naturally aspirated small block in the 10's would kick a$$.

My car is running pretty strong though. There were LOTS of street legal cars at the track on Friday and I only saw 2 that ran quicker than mine. A new Supra with rollcage and a blonde girl driving it running low 11's and a Subaru WRX STi running High 11's.

 

[10secgoal]

Lean might be mean. But can be dangerous. I didn't know how lean I was running until one night I lost et and MPH when I was bracket racing one night. As it got colder, I was actually running slower and slower as the night went on. But, with more fuel, you can run more timing. But every car is diferent. Just something else to try.

 

[washMO66]

Lean might be mean. But can be dangerous. I didn't know how lean I was running until one night I lost et and MPH when I was bracket racing one night. As it got colder, I was actually running slower and slower as the night went on. But, with more fuel, you can run more timing. But every car is diferent. Just something else to try.

You are correct and i will always profess that if you are not sure err to the fat side..........

 

[Vinyl66]

If it is running too lean then the extra fuel should help mph. I have never changed the jets in the carb. Is it easy enough to do during rounds at the strip when you are in a hurry
It does state in the Demon manual to err toward the rich side.