pretty dissapointed. (track results)

[prostreet1967]

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.

[bigjimzlll]

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

[prostreet1967]

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.

[RatPwrd72]

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?

[71Dragtruck]

Originally Posted by prostreet1967

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.

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?).

[Outlaw72]

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

[prostreet1967]

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

[prostreet1967]

was shifting 5-5500

[prostreet1967]

heres the exhaust

[RatPwrd72]

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?

[prostreet1967]

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

[prostreet1967]

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

[RatPwrd72]

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.

[Outlaw72]

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!

[prostreet1967]

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.

[Outlaw72]

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.

[prostreet1967]

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

[RatPwrd72]

Originally Posted by prostreet1967

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

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.

[prostreet1967]

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.

[djracer]

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

[RatPwrd72]

Originally Posted by djracer

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

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."

[tubbed 68]

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.

[prostreet1967]

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?

[prostreet1967]

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

[bigjimzlll]

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.