Can't figure it out

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Austin
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1976
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k10
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350
For some reason I'm not sure what I can't seam to get over 65mph or 100kmh. It's a 76 k10 single can short box with a rebuilt sbc 350 rebuilt th400 rebuilt np205. I believe it has 3.73 and its got a 3 inch lift on 33's. the problem is I can't get above 65mph or 100kmh unless I'm going downhill any idea why?
 

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Jims86

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For some reason I'm not sure what I can't seam to get over 65mph or 100kmh. It's a 76 k10 single can short box with a rebuilt sbc 350 rebuilt th400 rebuilt np205. I believe it has 3.73 and its got a 3 inch lift on 33's. the problem is I can't get above 65mph or 100kmh unless I'm going downhill any idea why?

If you have a cat, it may be plugged. Whats your timing set at?
 
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I don't have a cat and I'm not sure off hand what my timing is set at.
 

philjafo

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Is your transfer case in low range?
 

Jims86

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Austin, Does the transmission feel like its slipping at all? I am thinking you may have a fuel/ignition issue if not. The reason I asked about a cat, is if its plugged, it will significantly reduce power. Does it backfire at all? Have you checked the fuel filter/pump?
 
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Transmission feels perfectly fine it doesn't backfire. I haven't checked the filter or the pump they seemed to be working so we didn't check them.
 

Jims86

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Transmission feels perfectly fine it doesn't backfire. I haven't checked the filter or the pump they seemed to be working so we didn't check them.

hmm, well, first thing is to check timing. while warmed up, and in gear, timing should be 4 or 6 btdc for starters, you may want to pop the dist cap off, and make sure the advance weights are free.
 

Boone83K10

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he said he believes it has 3.73 gears... without confirmation he could have a much lower gear, like 4.56 or 5.14... that would severely limit your top speed especially with only 3 speed trans...

we use to have a 64 International Harvester pickup that topped out at 68 mph with a Dana 60 with 4.88 gears and 3 speed on the column.
 
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89Suburban

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:think:
 

bucket

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Let me ask a stupid question... Is the speedometer correct? I know 65mph in my Blazer is like 90-100mph actual road speed.

Also, if the 350 is stock, they don't really have a lot of balls to push a big lifted square through the wind at high speeds.
 

philjafo

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If the engine is running fine and its not in low range, lol. How about brakes, if they are dragging it will slow you down.
 
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The speedometer is like just barely off and I'm getting my brakes done in the next little bit so ill see after that.
 
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dhamp

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If your brakes are dragging, you'd smell them and see smoke coming off of them after running for a few miles. How strong does it run 0-65?
 

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