Wanna see 13s

[ont_guy_38]

So went to the track on Saturday and ran a 14.20 1.96 60 foot at 91 mph . Motor is a 350 standard bore,flat tops,air gap intake and vortec heads with a fair amount of porting done to them.The cam is a Comp , duration 228 int ,234 ext, lift int 480 ext 499 with 4/7 swap and 1.5 ,1.6 rocker combo,holley 700 cfm carb dp df ,Turbo 400 tranny with 3500 stall converter 4.10 gears and i was running a set of 275/60 drag radials , little bit of spinning leaving the line but not much . Would love to see 13s . first thing i guess would be ditch the clutch fan and go electric , any other tricks without building a new motor ?

[BigDan3131]

Put the battery in the back behind the axle. Get a fiberglass hood and take anything off you don't use on race day to eliminate excess weight. A built TH350 should give you back 20 horsepower. What kind of exhaust are you running? A full 2.5" system with 1 5/8" headers will help.

[OJ1988]

Always start with the basic tune, if you havn't dialed in it already. Timing, jetting ,etc...

As said, weight loss is always good. Take out what you don't need, replace stuff with lighter items when possible.

What rpm are you shifting at? What rpm are you at when going through the traps at the top end?

[ont_guy_38]

Running 1 5/8 headers , 2 1/2 inch exhaust with flowmasters , shifting a 6 and going through the trap at 6 also

[Marv D]

I'm wouldn't be surprised if you don't have enough cam to make power at 6000. If you are shifting by sweep of the tach,,,, it's typically 200-400 more for the eye, hand, shift lever, trans to react and actually be in the next gear. I'd 'try' shiftig at 5500 just to see if it like it,, then 6000, then 6500. You only find what the mtor / combination likes by trying.
I won't harp on the tunning thing,, but a $350 trip to a chassis dyno with a box of jets can make a 1/2 a second in a GREAT many vehicles.

Tune the motor, then tune the driving

And I'll be the one to ask,,, was there any before and after flow numbers to the 'fair amount of porting' . Not to say anything bad about anybody..... but I've seen the backyard home port job simply ruin what was a decent flowing set of heads.

[OJ1988]

Yeah, I was going to suggest trying lower shift points as well.

[C20-67_N_MO]

Okay this might be a newbie question but was this at a 1/8 or 1/4 mile drag strip?

[djracer]

That would be a 1/4 mile E.T.

What kind of ignition are you running?

You might look into some Caltracs.

[383Chevy]

Try to ease into it off the line so you dont spin even a "little" bit of spinning will hurt your time. also change your shifting to 5500 rpm .

[ont_guy_38]

Yes Marv I understand what you mean about the head porting , the guy that did them is pretty reputable . I myself did not get it done but the previous owner did and it was quite an improvement when he got the car back . He did tell the guy that I got the motor from that if he wanted to go faster a cam change would be in order and also I think i have #79 jets in the front and #89 I wanna say in the back but will try shifting a little earlier and DJ the ignition is just stock but I do have a msd sitting here to put in

[djracer]

Those jets sound way too big for a 700 cfm carb. A stock 750dp comes with 72's and 82's. I would try the 72's and 82's and see how the truck responds. I had a 71 street strip truck that went 13.50 with a similar but milder motor with a 650 dp.

I think the MSD will Help also.

[ont_guy_38]

thought the jets were a little big

[Marv D]

I can't even BEGIN to say how important one of these little things are. I bet it will pay for it's self in fuel saved within a year on a driver, and same for a missed tune burning $9 a gallon race fuel.


http://www.innovatemotorsports.com/

[ont_guy_38]

I have a 4778-2 carb which came with 66 & 76 but I see the 4778-4 came with 69 & 78 , where should I start ? You think 72 and 82 wouls still be ok DJ?

[gearheads78]

I would make sure you change only one thing at a time. If I was you I would not change anything other than shift point and see what you get. Make 2-3 passes and then change again.

Some things you should look in to
-underdrive crank pulley
-electric fan
-cal tracs
-dyno tune or at least get a wide band like mentioned above
-timing curve (my old street strip malibu went from 8.20's to 7.90's just with bringing the advance in sooner and limiting the total)
-tire pressure (I bet 18 to 20 will be close to the sweet spot on the heavy truck)
-flashing the converter vs brake stalling

I would be willing to bet with minimal money spent and a little careful tuning you won't be worried about 13.99 you will be looking mid to low 13's

[djracer]

I would start with the jets that came in the carb. I would say if they are as far off as you say it should make a huge difference.

[Super73]

Put it on a dyno, get it dialed in and you will have a good idea where to shift it You kill more than one bird by doing it that way.

[gofastbobby]

1. Install Caltracs
2. Run 13.80.
3. ???
4. Make Millions.
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[stich626]

we don't race dyno's and that only work if it's at the same or close to same sea level..
go to the track with a box of jets... and change only one thing at a time..

[OJ1988]

You gotta know how to read plugs if you aren't running a wideband, while changing jets.

Thats the good thing about a dyno tune. You can get real close a lot faster, than going to the track, esp, if you have not tuned a race car before.

[stich626]

Originally Posted by OJ1988

You gotta know how to read plugs if you aren't running a wideband, while changing jets.

Thats the good thing about a dyno tune. You can get real close a lot faster, than going to the track, esp, if you have not tuned a race car before.

true to a point, but you learn nothing, and if the shop is at 1500 feet above sealevel and the track is at sea level.. well.
at the track, it takes longer, yup but you learn along the way..

[OJ1988]

I agree, but if the guy has no tuning experince, he should really have someone that does at least go along with him at the track, so he doesn't make a costly mistake.

[djracer]

I would bet a bunch of money the stock jets in the carb would be a vast improvement!

[ont_guy_38]

Got them ordered
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[ont_guy_38]

Ok I got a terrible memory , for some reason I though they had taken the original 76 jets from the rear and put them in the front so I just got the 66 jets . Well took the carb off today and the jets I thought were in there were not . There was 68 in the front and 72 in the rear so is it strange to go that far down from what holley put in? . I apologize for my bad memory , should have double checked before I posted