My GMC truck is all original,including push petal start.When ever I get her on the freeway I can't go over 50mph.
Yup, that sounds about right. It's the rearend gear ratio, mostly. Does it really have a Chevy 216 in it? or does it have a GMC engine?
About normal. I think most of them had either 4.57s or 4.88s. Just wind it until it blows and then change it out for something else.....like a 454....
yep, start by changing the rearend with a nova or somthing along that line. If you want an even better ride swap out the trans.
If it's a half ton the stock rear gears are 4.11,3/4 ton is usually 4.56 but can be 5.14 50-55 is ok with a GMC engine in good shape .You say 216 Chevy engine? 50 then might be better. What do you mean by won't go faster than 50? It sounds like real noisy or that's all it'll go no matter what?
I drove my '48 Chevy with the 216, 4spd., and 4.56:1 rear for several years and always tried to keep it at 50 or below. Only a problem when on a cruise with others who are running cars that handle faster speeds better. I really wanted to keep it as orig. as possible including the 8 bolt split rims so I didn't want to change the rear. Gears better than 4.56 are very hard to locate so I opted for a swap to a T-5. Went with one that has the .73:1 overdrive. WOW, what a difference it makes! With the long bed truck the entire swap can be done with NO permanent changes to the truck. I did no cutting, drilling or welding at all and all the old stuff is sitting on a shelf if I ever want to go back. Shifter location is a few inches back from the 4spd. so I made a new floor cover instead of cutting the orig. Not a big deal as it's nearly flat. Grafted a shifter from another old tranny onto the one from the T-5 and bent it so it clears the dash and seat. A guy needs to know these trucks pretty well to even notice something is different. If your truck is a 1/2 ton then a rear end swap is a much easier way to go and can still retain the stock look. Good luck!
"Top speed"..the question should be top rpm before it blows. Gear ratio, as stated, dictates it's top speed.
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