Calculate 1/4

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340RULES

340RULES

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hi Guys,

After the following changes I went to the track Sat:

3.55 SG
Leafs, bushings
moroso Drag front shocks
timing 35

I drove 85 miles there, ran 5 time and drove back.


Set up, 1970 block 340 - 30 over, stock J heads, 292/509 purple, TCI street Fighter, PTC 3500, Edellbrock Performer intake, quick fuel 650 DP, Nitto 555, 30psi

First time at the strip with this car, hook up sucked in the left lane, X3 runs and spun each time bad. Right lane was much better, but still didn't hook up great.

Best run was 60' at 2.00, 1/8 at 8.5 =79.80

I know these numbers are not that great, but was wondering if this was a quarter mile track what time could be added for an accurate 1/4?

Also, I'm planning on some changes, manifold to a single plane, depending on the clearence 9 or 10 inch slicks on 7" rims. I would like to get down in the 1.7 - 1.8 60' without changing the gearing if possible? Any suggestions? Stroker?
 
With your 60 foot time I would try a softer tire. Also what are you running for a convertor as that will make a big difference as well. If the car will not 60 foot you are losing a lot of ET.
 
340RULES said:
nitto 555, rather hard compound
Click to expand...

That is a street tire. You need slicks or a drag radial if you want to get your 60 foot times to where they need to be. You will be surprised how your et will drop if you get traction, but you will also find any weak spots in your drive train in a hurry!
 
On the 1/4 mile you would have run (assuming everything is working) mid 13's (13.3-13.6 depending on who's online calculator you trust). For my car (this varies from car to car) I multiply my 1/8 mile ET by 1.575 to get 1/4 mile ET. Again, this varies slightly from car to car, but for mine it works with in a few hundredths every time. I calculated this using data from about 20 1/4 mile runs with my car.
 
8 3/4 rear, all HD axles (5 Bolt). running a PTC 3500 stall, it rocks out of the hole. Any suggestions on what type of rubber to run? BTW, I appreciate all the help. Just wanna make the 67 run decent
 
If you don't want to have to change them once you get to the track you could use a drag radials that is the same size as the tires you have now.
 
Take a look at Jegs. They have a bunch of different brands. Mickey Thompson might have something that will work for your application.
 
A couple thoughts..........

Until you get the 60's inline, you can just about throw your current 1/8th mile numbers away. Tire slip, going across the stripe at less the optimal rpm's and not enough time to build mph makes them almost worthless to me at this point.

Even though i can't make a recommendation, the drag radials do seem to be your best option. Only thing to add would be check the weather forecast well before venturing out as 85 miles from home is a long way to get caught in the rain on DR's.

Once you get that sorted out, i believe running that cam, that there is some performance to be gained by going to a more aggressive intake, RPM maybe?

Good Luck, Rick
 
Also with a stock rear suspension you are leaving some on the table. Caltracs and adjustable rear shocks would make a big difference in traction and 60 foot times.
 
I was running a similar set up, had a holly strip intake and 750 carb, but 4:88 gear and was low 12's. You are on the right track, timing seems a bit high to me but if that's what the engine likes go with it.

Trevor
 
I agree Rick, will be going to an RPM soon. Not likely I will drive that far again, have a friend with a trailer, this time I will be prepared better for changes. Trevor, I applied for a job up in Edmonton. Heard its a nice city.

I was thinking about Caltracks, but decided against it for practical reasons. I drive the car, its not a trailer queen, well not yet. I'll check out JEGS, see what they offer in the line of either a DR or slick.
 
There is no problem with running caltrcks on the street. Just adjust them so there is not as much preload and you are away, but remember to readjust once you are at the track.
 
If you move to Edmonton you are going to be in for a BIG shock! It is a nice city but you will FREEZE in the winter! LOL
 
Yes, I figured that, haha. Just testing the waters. I did live in Toronto, my daughter lives with her mom in Hamilton. Love Ontario, great place.
 
In my daily drive - Focus XR5 Turbo - i ran a 9.0 at 80mph and did a full run of 13.9 at 102mph on the qtr, So you have done a better launch than my front drive, so you are about .5 quicker than me - 13.4 is what I'd say
 
340RULES said:
Best run was 60' at 2.00, 1/8 at 8.5 =79.80

I know these numbers are not that great, but was wondering if this was a quarter mile track what time could be added for an accurate 1/4?
Click to expand...

I seem to remember a conversion factor of 1.57.

8.5 x 1.57 = 13.345

Rough guess on the MPH

79.80 + 20 = 99.80

Faster car will pick up closer to 25 MPH on the back half of the 1/4.
 
Thats all great info, I appreciate everyones input. I plan on making these numbers better, but for a street able 1967, I don't think 13.3-13.5 estimate with 3.55 is all that bad. Car does pull hard if it catches thanks to the 3500 PTC, thanks to other treads I contacted them and it was like night and day.
 
340Rules, are those Nitto's the NT555 or NT555R model? If they have an R on the end their a drag radial. That's what I'm using and while I can't say their the best they work ok when inflated properly and heated up the right amount. Mine like 27 psi. and a short-med. burn out.
 
take to exhaust shop get o2 bung welded into exhaust after header collector 20 bucks, go to dyno and get every extra hp out of ur motor with tuning thru ur o2 plug,200 bucks,go n craigslist and get some slicks 100 bucks...run 12s all day long
 
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