pretty dissapointed. (track results)
 

pass 1
60' 2.413
330 6.139
mph 60.28
1/8 9.661
mph 61.29
was spitting and popping let out of it.

pass 2
60' 2.207
330 5.935
mph 61.51
1/8 9.012
mph 77.28

pass 3
60' 2.218
330 5.884
mph 62.30
1/8 8.943
mph 77.54

truck has 468 bbc, turbo 400, ladder bars with coil overs, 9 inch ford with 4:56 gears, 33 inch mickey thompson sportsmans. it would spin pretty hard out of the hole. left foot braking about 2000 rpm. was hoping for low 8s

any one have any suggestions.

Re: pretty dissapointed. (track results)
 

First you need to get it to hook up. Those MT sportsman tires do not work well.
Check the tune up. It seems to be really down on power. Make sure the plugs and wires are good along with the cap. Make sure you have the firing order correct. What is your timing? What kind of converter? What's your engine combo?

A bad day of racing is still better than a good day at work :)

Re: pretty dissapointed. (track results)
 

its a 468 bbc turbo 400 2500 stall, 4:56 gears, spool, ford 9", ladder bars w coil overs. 2 runs it ran fine just spinning bad. went around water box backed up did short burn out.

also i noticed the trans shifted automaticlly a couple times.
timing is locked @ 34 degrees.

Re: pretty dissapointed. (track results)
 

What cam and heads are you running? What carburetor do you have? What RPM do you shift at? Did you let some air out of the tires to try and make it hook off the line?

Re: pretty dissapointed. (track results)
 

Try more timing, like 38* and make sure your timing curve has it all in by no more then 2000rpm( or by locked is it set at a dead 34 no advance?).

Re: pretty dissapointed. (track results)
 

Give me the specs on your engine, you might just need some "tuning"

I have a pretty stock 468 running 7.90's on motor with 4.10 gears. And I am LWB...!!

As far as hooking, that is a different issue but lets get some better times. Surely, you should be well out of the 9's in the 1/8

Re: pretty dissapointed. (track results)
 

well as far as specs on the engine i don't have any. when i got the engine it was complete with a bent push rod. the guy said he ran it a month around town and push rod bent so he yanked it out and went back with small block. i know its got a solid lift cam from what he said not really sure what to set the valves at. i reset all the valves at .021 just to see if it would hold up i think he let rockers get loose and push rod came out.

i let tire pressure down to 8 psi.

timing is locked @ 34, mechanical and vacum disabled
750 demon double pumper
steel heads (oval port)
edelbrock torquer II intake
1 3/4 long tube headers, 3 inch exhasut dynomax race mufflers
i know for a fact i need some plug wires, not arcing but just junk wires

Re: pretty dissapointed. (track results)
 

was shifting 5-5500

Re: pretty dissapointed. (track results)
 

heres the exhaust

Re: pretty dissapointed. (track results)
 

More timing (somewhere around 38 as long as the fuel is good) will make the engine run harder on top. With that said, you really need to know what cam you have before trying to turn it that tight. When you shift @5500 RPM is that because the motor quits pulling? Have you run a compression check on the motor?

Re: pretty dissapointed. (track results)
 

no i havent yet it seems to be running fine so i havent tried that yet. but now that u say that i have been fighting a problem with blow by as u can see by looking at first pic in post 7, oil was dripping out of breather onto header. i made a baffle to stop it

Re: pretty dissapointed. (track results)
 

i did ck exhaust temp at each header tube and noiced cylinders 5,7 100-150 degrees lower than the rest.
but like i said the wires are junk could be a problem.

also what plugs are yall using in ur big blocks

Re: pretty dissapointed. (track results)
 

I run NGK UR5's on my street truck (468) and Champion Race plugs (can't remember the number) in the 396 for the track. Also, the Bosch Super's from Autozone work surprisingly well. MSD now has a line of wires out that are considerably cheaper ($45 or so a set-build your own wires). I'm running those on my 468 with now problems. Sounds like a compression check is due of the engine has a bunch of blow by. It could be rings, but Big Block Chevy have a bad habit of chewing Valve Guides which will make it use oil and have low compression.

Re: pretty dissapointed. (track results)
 

Yep...start from scratch and check your tune. Start with a compression check. Bump your timing up to 38 degrees full advance as already mentioned.

Has the carb been tuned in? Those demons don't make the power they should right out of the box...you have to tinker with them. I pulled a demon out of the box and bolted it on....noticed a hesitation and tuned the whole thing in.....I picked up about a half a second!

Re: pretty dissapointed. (track results)
 

not much of carb tuner i can get it to idle and run decent but not to sure about jets. pulled plugs and they looked pretty good.

Re: pretty dissapointed. (track results)
 

Also, food for thought......a 750 was too small for my engine. It would give a lean pop and hesitation at about 5500 rpm. I slapped an 830 hp on it and also a demon 850. World of difference. Now I shift it at 6k-6200 on the bottle. I am almost certain that carb is too small.....it might seem fine just cruising around but it will more than likeley bang out high in the rpm range. Looks like you just need some good old fasshoned tuning......I run an NGK #8 plug....mine likes those much much better than the R45 delco plugs.

Re: pretty dissapointed. (track results)
 

damn no money for carb right now hopefully i can find some other problem.i know it has suspension problem i felt it hop a little and spinnin pretty bad

Re: pretty dissapointed. (track results)
 

Make sure the rear shocks are in good shape. No need for any drag type shocks, just a good working stock type. Also, checking all of the suspension for bind or free movement is essential. Even though those MT Sportsman's have a large contact patch, their not known for hooking really well.

Re: pretty dissapointed. (track results)
 

yeah ive heard they dont hook well but my uncle had them on his 55 with same suspenion and pretty much same engine in high 7s but that was 10 years or so maybe the material went down hill since then.

Re: pretty dissapointed. (track results)
 

I had decent luck with sportsman pro's on a 13.5 second street truck.

Re: pretty dissapointed. (track results)
 

As quoted from the Mickey Thompson Website-

"Sportsman offers an adhesive yet long wearing tread compound and rigid sidewalls making this the perfect tire for ''drivers''. Inner tubes are recommended to maintain proper inflation (except #672-1557)"

"Sportsman Pro"

A two-ply sidewall wrinkles like a drag slick, while still providing a street legal tread design. Ultra soft compound insures plenty of off-the-line bite. Inner tubes recommended."

Re: pretty dissapointed. (track results)
 

i had the sportsmans on mine and they wouldnt hook for nothin then i went to the et streets and what a difference they hook so well i would recomend them to any street strip car or truck.

Re: pretty dissapointed. (track results)
 

i think i may be on to something. not sure if it will solve problem all together but it may help.

was looking at truck and tried to bounce it in rear and it took both hands and some A$$ so i checked my uncles 55 truck and i could easily bounce it with one hand. not to sure which truck is correct his is just sitting but two different people did the backhalfes.

how can i find correct spring rate for my truck. what springs are some of yall using?

Re: pretty dissapointed. (track results)
 

talked to a tech guy at s&w race cars he said 170 springs way to stiff need to go with some 130s.

guess i will try that and post some results

Re: pretty dissapointed. (track results)
 

130's are to light unless you are only 600lbs on the rear....IMO
I am 1400 on ther rear...subtract the unsprung weight and I'm at 1000lbs. I run 170lb springs and they compress 3 inches with the weight of the truck on them.

Re: pretty dissapointed. (track results)
 

i dont know they just seem stiff and hard to push down and my uncles truck is soft and he said with that setup he wasn't spinning as bad as i do i know i need to check into some tires but that just don't seem right

Re: pretty dissapointed. (track results)
 

have been thinking the springs were to stiff now i think they might not by stiff enuff. there is no bounce in suspension seems to be to stiff heres my measurements

all measurements with truck on ground

before

shock bolts center to center

L 12 3/8 R 11 1/2

after

12 11

spring loaded

before

L 10 1/4 R 11

after

9 3/4 9 3/8

the right side was obviously preloaded the guy that did it said it would help with traction. i got them as close as i could to equal.

another thing when i let vehicle down it seems to me the shocks are compressed most of the way if not all the way. when i place jack under rearend 1 pump and tires are off the ground (as if the suspension is already compressed.

please feel free to ask for any more measurements that can help address this issue.

Re: pretty dissapointed. (track results)
 

Do you know the front axle weight?
How about the rear axle weight?

Before we can help you identify correct spring rate, we need to know your axle weights.. Do you have a local scale you can go get the above weights? Weigh the truck with you in the driver seat, front tires on the scale, then both front and rear tires on the scale. That will give you front weight, total weight, then subtract front from total to get rear weight.

Do you have factory front springs? If not, how long are they uncompressed and do you know the spring rate?
Can you tell us how much upward travel you have when you jack it up from the crossmember. Need to know when you start lifting taking the weight off the front tires.

Disconnect the front shocks and recheck. Did it make a difference?

It looks like you do not have factory rear springs due to the coil overs. Any idea of the existing rate? They might say on the spring.
Also what is the length of the spring?
How far are the adjusters turned up? (Bottom, 1/3, 1/2, 2/3, 3/4, top)

Do you have a front sway bar?

Lets start there..

Re: pretty dissapointed. (track results)
 

no the rear springs are coil overs but the shocks are not adjustable im using the cheap ones that came with the kit. havent upgraded to adustable coilovers yet.

the readings of the rear springs are in post above. but they are 12 inch springs the tag says 170 pounds.

the rear suspension has no movement. when i place jack under rear end one pump gets rear tires off th ground. i put jack stands under frame, removed rear springs reinstalled shocks and raised rear up and checked for binding. they went up and down smoothly.

Re: pretty dissapointed. (track results)
 

heres a pic of rear suspension can get more if needed.

i did lower the right coilover some.

Re: pretty dissapointed. (track results)
 

I'm not wanting to know shock setting for the rear.. I want to know where the coil over adjusters are sitting at your ride height. Are they turned bottom, up 1/4, 1/3, 1/2, 2/3, 3/4 or at the top of the screw on the body of the shock?

Your pic isn't blowing up for me.

Don't worry about no movement on the rear suspension with the jack. All your weight is already settled on the rear axle. Jacking it up from that axle isn't going to change that. Mine starts moving up as soon as I put the jack under it as all vehicle should do that.

Can you messure the length of the rear spring at ride height for me? Try to climb under the truck with out it on a jack. When you rais the back you could be putting more weight on the front axle and taking weight off the rear some.


How about the front info from the previous post.

Re: pretty dissapointed. (track results)
 

well i got truck scaled today readings are off a little.

front 2360
rear 1420
total 3760

i put front wheels on for front reading
put rear wheels on for rear reading
whole truck on for total reading.

maybe the lady writting it down meant 3780

Re: pretty dissapointed. (track results)
 

thats with about half a tank i forgot to fill up first

Re: pretty dissapointed. (track results)
 

Truck scales measure in 20lb increments. If it's right on the line 9-11 lbs, it will be hard for it to pick it up. But that gives us a real good start..

Your front end is not much heavier than mine was when I started messing with springs (Mine was 2,260). Here is the info for the spring I am using:

Moroso Sring 47140
240lb rate
17 3/8" long

Link: http://67-72chevytrucks.com/vboard/s...d.php?t=277773

Here is a picture of it after the springs have settled. http://73-ls1.com/63truck/track4-4/profile.jpg


I would guess that this spring would be pretty close to what you need / want. Now, it might sit a little lower than mine (I can take a few more pics if you want).


As far as the rear, let's play with that after you get the front doing what it should do..

Re: pretty dissapointed. (track results)
 

thanks alot shaun i really do appreciate all the help and advice. yeah some more pics would be nice. would also like to see the engine bay if u dont mind, i have been wanting a ls engine for my truck for the longest but they are so dam expensive.

so ur front weighed 2260 what does it weigh now?

i agree i will definetly get the springs, how about the shocks ur using any info on those would be nice.

i talked with chassisworks when i got back from scales and the wanted measurements of springs with weight on them and they said it might need a 150 spring but im going to wait and see what happens with the front.

Re: pretty dissapointed. (track results)
 

As I mentioned on the phone, I'm going to be putting a different front shock in my truck. If you want to give these a try with the new springs, pay for the shipping. If they work for you, well, then you can send me a little beer money :)

My front now weighs 2,050 and rear is 1,800 with a half tank of gas (tank is a 16ga cell in the back of the bed). That's me in the driver seat.

It weighed 2,260 with:
The front bumper on
7" steel wheels and 275/50/15 (Now 6" draglite with a 205/75/15)
Batterey in front

Re: pretty dissapointed. (track results)
 

well i have the drag lites, battery in bed, and no front or rear bumpers no tail gate, with a big block. with a half tank as well. i will gladly pay shipping and if they work out send u some beer money. just let me know when u get ur new ones in

Re: pretty dissapointed. (track results)
 

shaun, in my competition engineering catalog with the trick springs they say u may need to modify coil for proper ride height by cutting half coils at a time whats ur take on this should i go with a stiffer spring? i like the ride height of urs did u cut any on urs. proplaply order springs this week sometime only 86 bucks.

Re: pretty dissapointed. (track results)
 

Agreed on the carb,get at least a 850.Just for thought factory 427s had stock 830 cfms.

Re: pretty dissapointed. (track results)
 

Ok, knowing you have done the things I have and are about 300lbs more on the nose, you will most likely want either a longer (which will be very hard to fit) or a slightly heavier spring. I worked my spring backwards and added 300lbs to the figure. Here are the measurements I came up with..

18" long spring a 260lb rate
17" 300lb rate
16" 350lb rate

I think that might be a little on the heavy side. Here are the figures adding 200lbs in:

18" long spring a 250lb rate
17" 280lb rate
16" 330lb rate

The thing to remebder is if you have a really long light spring and it sits too low for your wanted ride height, you can always put a 1-2" spring spacer up top before putting the spring in. As long as you don't induce coil bind under bump, you'll be fine and store more energy than with the shorter stiffer spring.

Quick way to figure out where you will induce coil bind, count the gaps and measure then. Multiply them together (IE 15 gaps, .1 between = 1.5") So that means you have 1.5" of spring copression before bind. You would have about double that number for wheel/tire travel due to the geometry.

So when you call Moroso tell them you are looking for a spring with roughly the above rates/lengths and a coil bind of less than 7.5"

When they give you part numbers ask these questions:

Uncompressed height
Fully compressed height (Bind height)
Rate

Then I'll work the figures again for you with the info they provided.

Order a couple of them, set them in the truck and see what ones are closest to the ride height you are looking for keeping in mind they will settle 3/4 - 1"


I did not cut anything out of mine. Just did the math to find the right spring :)