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-   -   How fast will these things go, anyway? (https://67-72chevytrucks.com/vboard/showthread.php?t=706388)

Oberon67 05-07-2016 09:05 AM

How fast will these things go, anyway?
 
The subject line says it. What's the fastest you've gone in a square body, either in acceleration or top speed?
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flashed 05-07-2016 09:14 AM

Re: How fast will these things go, anyway?
 
Mine is a 74 short step with 3 on the tree and a 250 /6 cylinder so not very fast .

Oberon67 05-07-2016 09:26 AM

Quote:

Originally Posted by flashed (Post 7585226)
Mine is a 74 short step with 3 on the tree and a 250 /6 cylinder so not very fast .

I have the same drivetrain in an '81 long bed. A grocery-getter for sure, but I think I could bury the 85mph speedometer if I wanted to.

I haven't tried it. The reward doesn't seem worth the risk to me.
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TwoFiftyShifter 05-07-2016 10:39 AM

Re: How fast will these things go, anyway?
 
100 in my 87 V20. 4 speed 350. It wouldnt pull anymore after that;

KQQL IT 05-07-2016 10:55 AM

Re: How fast will these things go, anyway?
 
1 Attachment(s)
1/4 mile

Oberon67 05-07-2016 11:26 AM

Quote:

Originally Posted by KQQL IT (Post 7585297)
1/4 mile

Wow... Not too shabby!
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chrismoore701 05-07-2016 12:03 PM

Re: How fast will these things go, anyway?
 
I had my speedo pointed straight down. Put two quarts of oil back in after that run

Malo83 05-07-2016 01:58 PM

Re: How fast will these things go, anyway?
 
Quote:

Originally Posted by Oberon67 (Post 7585320)
Wow... Not too shabby!
Posted via Mobile Device

That's nothing, I can do that coming down the grapevine from LA to Bakersfield :lol:

KQQL IT 05-07-2016 02:14 PM

Re: How fast will these things go, anyway?
 
Quote:

Originally Posted by Malo83 (Post 7585434)
That's nothing, I can do that coming down the grapevine from LA to Bakersfield :lol:


Malo83 I have that double hump transmission crossmember, free to a good home.

Malo83 05-07-2016 02:49 PM

Re: How fast will these things go, anyway?
 
Quote:

Originally Posted by KQQL IT (Post 7585443)
Malo83 I have that double hump transmission crossmember, free to a good home.

PM sent.

esbstuff 05-07-2016 08:16 PM

Re: How fast will these things go, anyway?
 
Quote:

Originally Posted by Oberon67 (Post 7585221)
The subject line says it. What's the fastest you've gone in a square body, either in acceleration or top speed?
Posted via Mobile Device

1990 or so... 78 k10, 350, 4-speed, 205, 3.07's. I had the speedo pointed straight down and bouncing one night. 3 wide on a 2 lane interstate with a couple buddies. I think the story was the last one at the party had to buy beer... I didn't have to buy! Too afraid I would go splat now.

Jake Wade 05-07-2016 09:29 PM

Re: How fast will these things go, anyway?
 
Quote:

Originally Posted by KQQL IT (Post 7585297)
1/4 mile

That's impressive for a Small block truck if NA

KQQL IT 05-07-2016 10:38 PM

Re: How fast will these things go, anyway?
 
1 Attachment(s)
Quote:

Originally Posted by Jake Wade (Post 7585790)
That's impressive for a Small block truck if NA

Yeah, for now.
Just rebuilt it with better rods and opened up ring gaps.
Try a hundred shot out of the hole is the plan.

D13 05-08-2016 08:52 AM

Re: How fast will these things go, anyway?
 
1982 250 3ott 3.43 geared 3/4 ton, 80 is absolute limit.
1987 6.2 diesel 7004 3.08 geared 1/2 ton, fastest is 75, truck felt rock solid, issue was the noises under the hood.
I would suspect with a reasonable motor and OD trans with good gears that 120 would easily be possible. I read somewhere (Jim Feuling in CC in the 90's maybe?)that if the tailgate is open over 120 or so the vacuum bubble will close it - so I sure wouldn't want to try higher speed corners without some rear down force.

phillip123hastings 05-08-2016 09:05 AM

Re: How fast will these things go, anyway?
 
So not really fast whatsoever.

KQQL IT 05-08-2016 12:08 PM

Re: How fast will these things go, anyway?
 
Quote:

Originally Posted by phillip123hastings (Post 7586147)
So not really fast whatsoever.



3.08's @ 5500 with a 27" tire was way way faster that they should ever go on a S rated tire.
Thought the driveshaft was coming thru the floor when I lifted off the gas.

Matt Man 05-08-2016 12:19 PM

Re: How fast will these things go, anyway?
 
I had mine at about 90mph to test out driveshaft vibration when I had it rebuilt and shortened. Felt stable, but the wind noise was awful. I tried to push it farther as well but wouldn't go any faster. Oh well its a 81 4x4 pickup, not meant for speed haha.

foamypirate 05-08-2016 12:42 PM

Re: How fast will these things go, anyway?
 
Calculator says I should have been doing about 112 based on RPM (about 4200) in my 305/TH350/3.08/29" tire 84' LWB, but I have no idea how much converter slip was going on. Pedal was on the floor for several miles (sick baby in a truck with no AC in 97* temps, was trying to get home to get her cooled down ASAP). Wide open toll road, thankfully. Realistically, probably closer to 95mph based on how quickly I was passing people.

In my 88' R20 crewcab, max I've been is 90mph, testing acceleration with the LQ9/4L80E/4.10 combo. Speed limiter is 98mph, and the driveshaft is only good until roughly 115mph anway. I feel no need to take this one any faster than 90mph.

Oberon67 05-08-2016 02:25 PM

Quote:

Originally Posted by Matt Man (Post 7586322)
I had mine at about 90mph to test out driveshaft vibration when I had it rebuilt and shortened. Felt stable, but the wind noise was awful. I tried to push it farther as well but wouldn't go any faster. Oh well its a 81 4x4 pickup, not meant for speed haha.

I'm thinking someone... Not me, someone who can build... should put together a square-body for Bonneville.

The World's Fastest Squarebody.
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mongocanfly 05-08-2016 02:53 PM

Re: How fast will these things go, anyway?
 
There's already a square body salt truck...210mph.http://67-72chevytrucks.com/vboard/s...d.php?t=473510

mikentosh 05-08-2016 05:28 PM

Re: How fast will these things go, anyway?
 
LS motors and lowered trucks are a wonderful thing...I took Cannonball C10 down to LA a few weekends ago and got into a fast moving crowd of Friday evening traffic. It was more than happy to cruise at triple digit speeds on and off for a couple of hours. In fact 6th gear is only useful above highway speed as its doing 2000 rpm at 80mph. I'm attributing the stability to lack of airflow under the truck and wide track; the front air dam sits only a couple of inches off the pavement.

Downside to this is that vertical windshield collects a lot of bugs at speed haha

Got a nice photo of it just off the 5 in Coalinga too :)
http://i782.photobucket.com/albums/y...shq9d8qsx.jpeg

Oberon67 05-08-2016 05:29 PM

Quote:

Originally Posted by mongocanfly (Post 7586439)
There's already a square body salt truck...210mph.http://67-72chevytrucks.com/vboard/s...d.php?t=473510

Interesting... But I bet someone here could beat it.
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Alex V. 05-08-2016 06:51 PM

Re: How fast will these things go, anyway?
 
Fastest I've had my '85 C3500 (454/TH400, 4.10's) is 85, but it wasn't done yet. 90 wouldn't be too hard, and I think it'd break 100 but everything under there is spinning so fast at that speed I'd rather preserve the truck than take the chance. :D

mongocanfly 05-08-2016 07:15 PM

Re: How fast will these things go, anyway?
 
My 81 c30 with 6.0, nv4500 and 4.10s will hit a 100 before you know it..when they had it on the dyno they had it showing 140..

Big Port Jimmy 6 05-08-2016 07:22 PM

Re: How fast will these things go, anyway?
 
Funny, Ive been thinking of taking my CCSB to the ECTA in Wilmington for the first race next year. It should be a C/PP or C/MP. No real shot at the record as C/PP is a 163 and change. Maybe run up in B? 5.3/4l60e 3.42 gears 29 inch tall tire 3500 through the traps is 130ish but that would be a real maybe. 115-120 is more realistic. Just got to run the numbers and buy some stuff.


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