Thread: Engine Upgrade

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I just bought an 86 Chevy Silverado 2WD. I don't know why but I've always loved this Chevy model. And after trading in my 2004 2500 4x4 for a mini van my wife let me buy an old beater truck. Well I plan to soup this puppy up. But first I want to get a new engine and trans before doing any body work. I've always loved automobiles and now have the time and money (not a lot) to really dive in. I'm a newbie but a fast learner and am not really affraid of taking on a big challange. So my question here is My current engine is a standard 305 5.0L 4BBR, and it leaks oil from pretty much everywhere. I want to know what would be a nice upgrade and how hard would it be? I would like to use my current intake manafold, carb, etc (because it has been newly upgraded), how big can I go with out needing to buy all new parts? I was thinking of upgrading to a 350. Any suggestions?

Sell all that small block stuff on e-bay and start with a big block. You'll be way ahead of the game horsepower-wise and money-wise. 454's are getting harder and harder to find, but you can still find the tall deck 427's and 454's for cheap and they make a good foundation. There is a ton of info on this forum about them.

http://www.clubhotrod.com/forums/sea...der=descending

http://www.clubhotrod.com/forums/sea...der=descending

SUGGESTION; keeping all your questions and comments on one thread will work better than having several threads going at the same time and will keep all readers focused.

The biggest thing you have to remember is that an engine is a system. All the parts need to work together. If you change other "stuff" in your engine, but keep your old carb and intake, you'll likely degrade performance rather than increase it.

Based on your other posts, you need to accumulate quite a bit more knowledge before you dive into your engine and start changing parts. Also, you'll need more info than you are going to be able to get by dropping in on this (or any other) forum. One risk in forums is that you may get info from people who have no clue what they're talking about. I'm obviously NOT talking about you, Richard - or anyone else specifically on this forum, but we've all seen it happen

Check the Amazon on the internet, and get a good book on small block (and/or) big block Chevys and do some reading.

Originally posted by Henry Rifle
The biggest thing you have to remember is that an engine is a system. All the parts need to work together. If you change other "stuff" in your engine, but keep your old carb and intake, you'll likely degrade performance rather than increase it.

Based on your other posts, you need to accumulate quite a bit more knowledge before you dive into your engine and start changing parts. Also, you'll need more info than you are going to be able to get by dropping in on this (or any other) forum. One risk in forums is that you may get info from people who have no clue what they're talking about. I'm obviously NOT talking about you, Richard - or anyone else specifically on this forum, but we've all seen it happen

Check the Amazon on the internet, and get a good book on small block (and/or) big block Chevys and do some reading.

Good Info, thanks!

Originally posted by Henry Rifle
The biggest thing you have to remember is that an engine is a system.

I was attempting to learn more about cams and came across this web site.

Do any of you choose the cam last?

Most of what I read is choose the cam and add parts with specs to accommodate it.

Checkout the section on Valve timing.
Interesting Engine Theory

More good reading for new motor people -
Article on Cams

This one is really good on cams and timing.
Elgin's Rant

Bert

"Do any of you choose the cam last?"

Every time.

Most beginning hotrodders will change the cam the first thing, usually in the wrong direction. Most of them have a car or truck that is a dual-function vehicle; daily driver and once-in-a-while drag car. With stock compression ratio, stock heads, etc., they want to stab in the hairyest cam they can find, thinking that it will really wake up the motor and make the vehicle a world-beater. Nothing could be further from the truth. They have moved the intake closing point so far up the scale that there is little intake charge captured and subsequently, very little cylinder pressure generated on firing. Now the vehicle won't pull the hat off their head at low rpm's and there is no longer sufficient manifold vacuum to operate power brakes or other accessories. The motor won't idle where it once did, so the whole driveline clunks whenever the vehicle is put in gear from neutral and it's a chore to hold the brake against the stock converter.

Been there, done that waaayyyy too many times.

Jack said it best......
"The biggest thing you have to remember is that an engine is a system".

Here's some further info I put together on cam selection.....
http://www.streetmachinesoftablerock...topic.php?t=78

Hey - Its beginning to make sense now.
Well - at least understand one more cam parameter -

My curiosity was aroused when the 283 cam question came up a while back and a 327/350 cam was suggested:

Part # E903= 223/223, 447/447, 114 Street/strip .4bbl,headers
almost identical to the 327-350 cam

But prior to that I had read of 270-284 duration cams more than any other specification. How can a 'lowly' 224 Dur cam be worthy.

It must have to do with the peak operational RPM you eluded to:

techinspector wrote - What you need to know is that with any cam you choose, it has a "window" of operation in which it will be efficient. That window is about 3,500 rpm's . . .
... If you install a cam with a long duration, it's going to have the characteristics of being efficient in a window of operation that will be too high on the rpm's to do you any good on the street

Bert

Bert, you have to know whether the writer is talking about advertised duration or duration @0.050" lift.

The 270-280 you're seeing is advertised duration and is normally taken at a tappet lift of about 0.006".

That 223-223 cam spec is measured at a tappet lift of 0.050".

So - the advertised duration obviously begins before .050 valve lift. Advertised lift must be the point where the valve actually begins to lift, to the point where it is completely seated.

The 223 lift @.050 cam could have an advertised lift as high as 280?

I've read Elgin again -

It seems that it all boils down to the relation of duration to TDC/BDC. In other words, on the intake stroke, how soon after BDC the valve closes. And the longer duration favors higher RPM.

Still not sure what my stock 283 would like as a good mid-range cam, once I get done with the suspension.

How would I measure required lift relative to CFM throughput?

Considering the cam as the last choice, I need to see what I dealing with first in rods, pistons and carb, then

I'll be back - Thanks for the info

Bert

"Advertised lift".....You're gonna start confusing yourself. There is no such thing as advertised LIFT. There is only LIFT at the cam and LIFT at the valve. LIFT at the cam is a direct reading measurement of the difference between the base circle of the cam lobe and the highest eccentric point of the lobe. LIFT at the valve is a the actual movement of the valve from its seat (with the tappet on the lobe on its base circle) to fully open position (with the tappet on the lobe at its highest eccentric point of the lobe). Lift at the valve includes a theoretical rocker arm ratio which magnifies the cam's work. In other words, if the tappet lift at the cam is 0.300", then the valve lift with a 1.5:1 rocker ratio would be (0.300" X 1.5) or 0.450" at the valve.

There is advertised DURATION and there is DURATION @ 0.050" lift.

"The 223 lift @.050 cam could have an advertised lift as high as 280?"

Yes, it could. The smallest difference that I have encountered was with a roller cam with 37 degrees difference between advertised and 0.050" duration. The more difference there is between advertised and 0.050", the lazier the design, but the easier it is on the valvetrain. Back in the 50's, I remember some Chevy cams that had 70 degrees difference. In other words, 300 degrees advertised and 230 degrees @ 0.050". (Which would have meant 35 degrees on the opening ramp and 35 degrees on the closing ramp between about 0.006" and 0.050" tappet lift. Very smooth and easy on everything)


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