Re: 1973 el camino luck of power

by dynchel Sun Oct 19, 2014 10:50 am

Gears will help, but you still need some power to get the car moving, I learned this first hand.

by rogal_tx Sun Oct 19, 2014 11:03 am

I will check my rear end and get back to you. So no matter what I might be looking to get comp cam like pila was saying.

by dynchel Sun Oct 19, 2014 12:13 pm

You can always bolt some small valve 305 heads on it. (A common circle track mod) I did it, it works, lots of low end torque. It does tend to run out of steam at higher rpms,but on my street car with 373 gears its perfect.

by 77mali Sun Oct 19, 2014 3:34 pm

bracketchev1221 wrote:No you don't want that. A spool is not good for the street. Race gears are softer than street gears and wear fast. And 4.88 is a ratio way out of range for what you need. You need a limited slip differential like an eaton or even an auburn. And a 3.42-3.73 gear is all you would need.

X2 ... maybe even a 3.08 would be good depending on what you end up doing to the engine. A 4.88 & 3.73 are nice for off the line launches- good for quarter mile racing & such but you loose HP on the top end and you'll be revving higher @ highway speeds unless you have an overdrive transmission.

I'm not saying it's good or bad and it's very true that many people use 305 heads for low end torque but I think the same can be accomplished by a good cam/cylinder head & torque converter combo. I had 305's on my car when I first got it & they were the swirl polished type. I had a bad crack on my block between two cylinders as a result of either the wrong head gasket being installed and/or too much compression being made.

by rogal_tx Sun Oct 19, 2014 5:30 pm

I will mainly be driving it on the hwy so I defenetly don't want to loose hp by using higher gears I guess I be looking for 3.08 - 3.73 gears

by dynchel Sun Oct 19, 2014 6:03 pm

373's are a bit steep for the freeway...unless you like driving 60 mph. Any faster and you're at 4000 rpms.

by rogal_tx Sun Oct 19, 2014 7:05 pm

Sounds like 3.42s would be perfect fit, since my regular speed is between 70-80

by dynchel Sun Oct 19, 2014 7:06 pm

I agree, 342's was the steepest gears the factory put in these cars.

by bracketchev1221 Sun Oct 19, 2014 8:20 pm

As much as I keep thinking about 3.73's for mine, I think the 3.42's will be the best compromise. I have had 3.42, 3.73, and 4.10 in street cars. Getting older, I think a 275/60-15 tire and a 3.42 will be just fine for driving. Now if you want to talk about the engine there are a few things you can change to wake that up.

by dynchel Sun Oct 19, 2014 8:26 pm

I have 295/50/15's with 373's. Not a freeway car, fun around town though. Hey ray, did you ever try the 305 heads on a 350 trick?

by bracketchev1221 Sun Oct 19, 2014 9:16 pm

No, I never did. I'm going to sound like an old fart, even though I'm only 40. I got out of the small blocks before that came about. For me, we tried to get the 64cc camel hump heads. At that time you could get the Sportsman II heads were about the only affordable option. My 78 Malibu in the mid 90's had the 441 casting 76 cc heads with big dome SRP pistons to make about 10.7-1 compression. Aluminum was out of the question. I had big blocks from about 1992 until I got my Nova in 2009 which I put the 195 AFR heads on.

by rogal_tx Sun Oct 19, 2014 10:06 pm

So what things are you talking about to wakeup that 350? Is there a affordable way to do that?

by bracketchev1221 Sun Oct 19, 2014 10:32 pm

First we need to know, what gear you have in the rear. I can tell you, comparing a 2.73 gear to a 3.73 gear, changing nothing else the car saw 1 second gain from a 15.20 to 14.20. So that requires no change to the engine. If you have a late model L48 corvette engine with 76 cc heads and a 8.5-1 compression, just going to a 64 cc head can net you a 9.5-1 compression ratio. 58 cc of the 305 heads can get you right up to 10:1 compression which is about as high as I would go with a steel head. This in itself is not a HUGE performance improvment, however, it allows the use of a larger camshaft which together with a compression increase can show 50-100 hp gain. Add a performer rpm intake and 600-650 cfm carburetor, you could easily wind up in the 325-350 hp range compared to the 200 you probably have now. Right now, the Vortec cylinder heads seem to be the best flowing, most affordable heads out there. They do require some work over .480 lift on the cam, but otherwise they flow better than any previous chevy 58-64 cc heads. Also in the bellhousing area, you can swap out the torque converter from a stock approximate 15-1700 stall speed converter to about 2-2200 rpm stall speed. This achieves the same thing as riding a bike in a lower gear. You can pedal faster and easier and the bike accelerates quicker.

by rogal_tx Sun Oct 19, 2014 11:17 pm

I will find out tomorrow what gears I have right now and I already have performer rpm intake with eldebrock 650 cfm carb

by chevellelaguna Sun Oct 19, 2014 11:37 pm

Do a compression check on your motor before you start any mods.

by pila Mon Oct 20, 2014 12:15 am

X2 on the compression test. You need to know the health of the engine before any major mods.............

by rogal_tx Wed Oct 22, 2014 6:46 pm

I checked rear end:ACC 344 1.
I guess that 3.44? If that's the case than I probably should not change it right? Haven't had chance to check the compression yet but will tomorrow.

by bracketchev1221 Wed Oct 22, 2014 7:05 pm

I think AC is a 2.73.

by 77mali Wed Oct 22, 2014 7:28 pm

For 73 AC is 2.73- CC is 2.73 w/Posi. It's been a while but one of those letters in the sequence is for the plant code & the numbers are date code.

by bracketchev1221 Wed Oct 22, 2014 7:57 pm

Good for cruising rpm, not so good for acceleration.

by rogal_tx Wed Oct 22, 2014 8:07 pm

What gears would be good for acceleration?

by dynchel Wed Oct 22, 2014 8:18 pm

rogal_tx wrote:What gears would be good for acceleration?

4.11's. The higher the number, the better the acceleration...at the expense of top end.

by bracketchev1221 Wed Oct 22, 2014 8:29 pm

You can compromise a little on this by maybe not putting so much gear in it, but increasing the stall speed of the converter. The trick to quicker acceleration is how quick you can get the engine into its powerband. So you can do it with gear, or make the converter slip to accelerate the engine a little faster. But the converter won't affect your cruising rpm too much as gears do. I plan on using a 3.42 gear and about a 24-2600 stall converter in mine.

by rogal_tx Wed Oct 22, 2014 8:37 pm

I think I will look for posi Rear end. How would I know what stall converter I hav ? I'm pretty sure its original from 73

by bracketchev1221 Wed Oct 22, 2014 9:01 pm

Stock is generally around 1500-1700. Just enough to slip with your foot on the brake at a traffic light.

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