El Camino Drive Train question

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Dalecamino

Dalecamino

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Indianapolis, In.
My '81 EC was built with a V6 and 700R or, whatever trans they used with V6. They were already removed when I bought it. We put a 350 with a 350 Turbo Trans in it. Here's the question....do I need to change the pinion and ring gear? I don't run a Tachometer, but it seems the engine is running RPMs kind of high. Doesn't get hot. I ran into this with a '50 Ford P/U years ago. A guy dropped in a 350, and had a drive shaft fabricated, without changing the rear end gear. That one ran HOT. Anybody know where I can find my answer?
 
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If it had a 700R4, then it came with an overdrive. Going to the turbo350 removes that.

Whether or not you need to change the rear end depends on how fast you want to go, how quickly you want to get there, and what RPM you want to run at that speed.

If you lower the rear end, your RPM will drop at speed, but you will lose low end torque and acceleration. Additionally, you will get a higher top speed at a given redline.
 
You need to figure out what your rear end ratio is..... with an overdrive as the original tranny, Im figuring you might have a lower (numericaly higher) rear end. best bet is to pull the cover off the rear and rotate the axles to find your ratio stamped on the ring gear... then you'll have to do the math. You should see a number like 41:11, then divide the larger number by the smaller and get your ratio..... 41/11 =3.7272727 (3.73 gears). The higher number you have, the lower the gear ratio and the higher the RPMs are going to run on the highway. If its too high for you to live with, you can either pay a gear shop to swap the ring and pinion... or, since you obviously can use a wrench, get a higher (numerically lower) rear and swap them out.
 
If you're going to use it for short runs, I probably wouldn't change the gears. Long trips would be different. It most likely will be a 3.02 gear set. The 2 other common gear sets were 2,91 and 2.73, Early 80's is when they thought taller gears solved the worlds problems. Believe it or not, I owned an 83 4x4 with 2,73 gears and a 12" clutch. You couldn't take off uphill without jumping up and down for a while. Just my thoughts anyway.
 
Yeh, I don't think it was a 700R4 as there is no overdrive indicator on the dash cluster. I need to make long trips on the highway with it, hence my concern. Thanks guys, for the advice.
 
If you want to get where you are going right NOW then a 4:11 or 4:56 or 4:88 ratio will do that, but at 65 on the highway you will be wishing you had another gear because she will be wound up tight !! Get in the 3's if you want the best of both worlds!!
 
Hey Chuck, my chevelle had 3.23 gears and a two speed powerglide. It would do a hundred in low:biggrin:. If you need any gears let me know, being a die hard chevy guy, i've got quite a few laying around. Heck I can even get you new ones really reasonable.
 
EBorraga said:
Hey Chuck, my chevelle had 3.23 gears and a two speed powerglide. It would do a hundred in low:biggrin:. If you need any gears let me know, being a die hard chevy guy, i've got quite a few laying around. Heck I can even get you new ones really reasonable.
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You da man Ernie! I'll let you know. I'm gonna have to replace the pinion seal anyway. Just wanted to get the ducks lined up, so it only comes apart ONE time. :rolleyes: And, not keep this guys lift tied up too long.
 
If you want a quick way to check the gear ratio jack up the car and rotate the rear tires 1 time, count how many times the drive shaft goes around, you'll probably want to mark it.

As others have said the lower the ratio the slower you'll accelerate but you'll get better gas mileage as the RPMs will be lower. High gear ratio will accelerate quicker but will kill your gas mileage.

AK
 
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