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Hey guys,

Thought that this discussion area could use a good thread, one I'm assuming you hot-roders can take and run with, here it is. I'm the owner of a '66 C-20, with original 283 engine. I was on the road the other day and had the opportunity to open that baby up, pedal to the medal. I did , and it did not have near as much power as i would've assumed or hoped, but im not a gearhead so my knowledge is limited. As usual I was hoping that my fellow stovebolters (you guys ) could enlighten me, give me some ideas or suggestions on how to maximize the horsepower and torque with the engine I have . Any engine modifications, components, or products that you think may be worth while. I'm like a sponge, eagerly waiting to absorb all the information you throw at me.

thanks,
Nolan

An aluminum dual plane intake manifold with a Quadrajet or AFB type carburetor. A mild camshaft. Dual exhaust with 2-2 1/4 pipes & low restriction mufflers. Don,t expect it to be real fast because those were geared pretty low.

heads. get some double hump heads and let her breath. along with some headers to get rid of the exhaust. along with the suggestions of Wrenchbender, i'd say she'd be pretty well off.

Speed is money.
How fast do you want to go?

My order is something like this:
1) Tune up. Make sure what you've got already is runnning its best. Also, with ignition OFF, look down the air cleaner while a friend mashes the gas to the floor. Throttle should be up against the stop at the carb. You'd be surprised how often it's not -- meaning you never get to WOT.

2) EXHAUST. If you're starting with stock manifolds and a single exhaust, changing to headers and duals is (relatively) cheap, gives a nice performance boost, and will improve your gas mileage.

3) Intake & Carb.

4) Cam

5) Heads....

Cheers,
mark.
'51 KY 3100

BLOWER

There's no replacement for displacement.

Seriously, if you start changing things on an old engine, like cam and heads, it's either gonna start using oil or it's gonna come apart or both. If you're going to do performance upgrades, go all the way. That will include a lot of machine work, new pistons, bearings, gaskets, etc. Speed equals money, usually a lot of money.
Good luck,
Scott

Big block. No better answer out there.

Maybe that new crate 572...

My big block truck almost leaps with a little push of the pedal.

I have a 66 that came with a 283 just like yours. I too was dissapointed in the power so I decided to upgrade to a 350. Bought a rebuilt short block, found big valve heads, hotter cam, intake, 4bbl, dual exhaust. All of that cost about $1500 and I do have some more power. But it still won't snap your neck back and plant you in the seat. So if i had it all to do over again I would put 4bbl heads on it with a performer intake and carb and do a nice set of dual exhaust. It would save untold hours of labor, cost half as much, you would feel a difference, and best of all not have your truck laid up for months. Just thought you might want to hear the other side of the story.

In a recent issue of Classic Trucks magazine, they show a build up on a used 307 engine. Check it out. They got over 300 hp out of a pathetic 307. A whole lot of horsepower can be found in a set of heads. The stock 283 heads do not breath very well. Upgraded intake and exhaust systems will be nullified by the amemic flow of the stock heads.

Phil

Phil: Not being one that disagrees with people I had a little 307 in a 1968 Chevelle 300 this was in 1970 putting out 270 hp. won many time in my class at the strip.

I found that article in Classic Trucks very good and very interesting. Ben

popcorn The Truth is Out There (Truthfully I want a big honkin HEMI)

Put in new rings and bearings.

202 Powerpack heads. (Some people will argue in favor of 194's.)

A good 4 barrell around 500 cfm. One of the old 4GC carbs would be really good on a 283. You can often find them on ebay, but watch out; there are a bunch of different sizes.

Look at an old "Motors" motor manual and find out the specs for the hottest cam GM used in a 283, and than get one as close as you can.

Mallory dual point distributor and an Accel Super Coil with Accel wires.

Change your differential to a pos-trac around 3.42:1.

Get rid of your stock single exhaust and go with Hooker Headers dumping straight into a pair of Purple Hornies.

Paint it black with a rattle can and drive it like you're 16 and just stole it!

Now you're old school brother.

Boo

What would be the first and easiest (cheapest) step in this process. Even in regards to oil and tranny fluid you prefer, as wrenchbender said it is geared low & I'd like to do anything I can, to start bettering engine performance with the budget I'm on . Thanks again for all the info. as usual guys.

Nolan

Does this truck have a stick or an automatic?

If it is a manual transmission you probably have something like 3.72:1 or 4.11:1 differential gears. Swapping those out for 3.42:1 gears would make a good improvement out on the hiway. Most of these old chevy trucks are geared so you can pull a house off its foundation, but you can't cruise at 70 and get decent gas milage.

As I mentioned above rings and bearings are usually a good idea in these old motors, but if it doesn't smoke or knock and has decent compresion you may be okay for quite a while without them. In that case two of the easiest and cheapest improvements would be a small 4 barrel carburetor and dual exhaust. You can have your single exhaust converted to dual at any muffler shop without buying headers. It's cheap. However, you won't get the maximum benefit of improved carburetion and exhaust without better ( more performance oriented ) heads.

You say you are not a "gearhead" so let me put this in simple terms. The following items represent "paths to power."

Carburetor,
intake manifold,
camshaft and valve train,
compression,
ignition,
exhaust.

All these "paths to power" have to be more or less capatible to derive real benefit. You can put a nice edlebrock four barrel and an aluminum hi rise manifold on your stock engine, but just like you can't suck a bowling ball through a soda straw pouring extra gas in won't do much good unless you do somthing about those little bitty intake valves. Bigger intake valves means there's more going in, and so there is more that needs to get out, et.

At the very least I think in order to be happy you need to do the following:

4 barrel carb and manifold;
194 or 202 heads off an old 327;
mild performance camshaft;
dual exhaust with glass packs or turbo mufflers;
and while you're at it go ahead and replace the timing chain and gears.
You'll have it apart anyway when you're doing the rest of the work.

This would be an excellent project for a "NonGearHead" to make his bones and become an official member of our "brotherhood of the busted knuckle."

Good Luck,
Boo

Boo gives good advice. Also, buy a book on hot rodding small block Chevys. The book will list the small details that we may forget to tell you. There are certain processes that have to be followed when replacing parts. For example, when bolting down an intake manifold, you want to tighten the center bolts first and work your way to the outer most bolts. There are many minute, but important details that you need to know to successfully tackle a project like this.

You need to learn sometime, so why not now.

Phil

Boo's got some great suggestions. These are things that can be done without pulling the motor and should wake it up somewhat.

But remember...you've got a heavy truck (relatively) and a small motor (relatively.) The 283 isn't known as a torque monster at all. So whatever performance you get out of it won't be earth-shattering.

However, as Boo has alluded to, the motor's just an air pump. More in, more's gotta come out, equals more power. All of the components play their own part. If you do the intake first, the flow will be restricted by the heads and exhaust. If you do the exhaust first, the intake and heads will be the bottleneck...and so on.

The cam also plays a part in it and an "RV" type cam wouldn't hurt in a heavy truck like yours. I wouldn't suggest buying a cam with lots of lift and duration, because they're meant to add horsepower in the upper rpm ranges..and the lower torque range can suffer...or not be taken advantage of as well.

A quick way to start would be by getting a set of cheap headers and Purple Hornies. I've used 'em and they're a hell of a lotta fun. But if you're in a quiet residential neighborhood, maybe a nice set of 2.5" dual exhaust pipes with turbo mufflers will do a better job of getting the exhaust outta the way without a lotta noise pollution tickets.

Personally, I run a 292 I6 with split headers and Cherry Bomb glasspacks. Yeah..it's old skool and that's exactly what I wanted. I also run a 625 CFM Carter AFB carb on it and it runs great.

Anyway, once you're done the exhaust and gotten familiar with some of the things under the hood, you might want to attack the carburetion and intake manifold issue, just to get familiar with doing it...cuz if you change heads and cam later, you're gonna do it again. I'd suggest an Edelbrock 2101 Performer manifold. I don't think you'd gain a lot by going to the next step up, the RPM.

As for carbs, I'm partial to AFBs...Carters or Edelbrocks. A 1403 (500 CFM) or 1406 (600 CFM) with electric chokes (I need the electric choke where I live) would be what I'd go with. I've used 1406 carbs on 305s without it being too much...and if you ever decide to replace the 283 with a 350, it'll be just right.

Then the cam and heads. This is a little more involved, but it's not all THAT much harder. Those cast iron heads are sure heavy to lift outta them big ol engine compartments. If ya got an extra $1300-$1500, you could get aluminum heads...but then that'd be sorta silly. If you can find the Power Pack heads, those would be great. I'd have a machine shop do a valve job and replace the valves, guides and seals for a long-term solution. I've cheaped out on this before and regretted it.

If yer gonna replace the heads, for sure do the cam, lifters and use a good double-row timing chain and gear set. This might just do as much to make things more consistent than many of the other items. If yours is original, I bet it's stretched all to hell. Btw, Summit Racing sells a cam and lifter kit for $80 (I'd go with an 1102 or 1103 version.)

When ya get that back together and running, you'll prolly have around 220-250 hp. Not enough to stop the presses, but prolly a lot more than you have now.

Finally, if you wanna see the smoke and oil and parts start exiting thru the oil pan, you could always add a 150hp shot of nitrous. That'd be kool for a while, but I doubt that the motor would live very long that way. Like maybe 4 or 5 passes down the quarter mile if you've got a worn bottom end. Btw, this type of cataclysmic event is known as "oil pan failure." That is, the failure of the oil pan to hold all the blowed-up parts that are rattling around inside the crankcase like shrapnel.

Now...if I was gonna do it...I'd pull the little 283 out, set it over in the corner of the garage as a doorstop and build up a 400 (406 or 408 with a .030 or .040 overbore) smallblock, Vortec heads, Vortec RPM manifold and 750 CFM carb. Ohh...and a nice healthy torque-monster cam. I like 400 motors.

There are several stories of engine build-ups that I've done over the past few years on my website. Unfortunately, I've had to sell most of the cars in the last year because of medical problems. But if you go to the "Dearly Departed" section at the bottom of the main menu page, you'll see several of them that have had motor built...and you can also see the 2 remaining V8 vehicles I have run 400 smallblocks: the 80 El Camino and the 85 Monte Carlo (alleged salt flats race car.) The url for my site is in my signature.

Good luck with your project and I hope you don't mind my wordy response.

ScTrucker --

Don't get confused by some of the terminology that we've used. What Samwise called "double hump" heads, and Chevyasylum called "powerpack" heads, and I called "202" heads are all the same thing. Asylum suggested you get a good book on hot rodding small block chevies, and that is a GREAT idea. Not only will it put detailed info at your finger tips, it will also help you learn the vocabulary.

Boo

For a good upgrade on heads for your 283 use 305 heads small combustion chambers ,bigger valves and runners plus accessory holes.Best part is very common and cheap.

You really dont say what the problem is.If it is just top speed that old 283 should be plenty.You say you have a C20,so it is probably geared real low,and your top speed will be pretty low.As for engine power there are plenty of 283s running around putting out over 300 horses.Check out your gear ratio before you start throwing money into engine upgrades.Just my 2 cts.worth.

I agree w/ Dale - gearing's the first thing you should attend to, especially if you mean "top speed" when you say "power", and if yer budget is tight - the 283 I'm running is stock except for being rebuilt 60 over, and it's got lotsa go for a truck, even w/ 3.90 gears - if you want more top speed find an overdrive trans, cheapest option

Bill

Wow, you guys are awesome. Radley it is an automatic conversion, at least I'm pretty sure. Thanks for all that info. in terms I can comprehend. It looks like from what you guys are saying & what I've experienced on the road the first thing I need to do is fix the gear ratio, its sickening how low it is. Actaully I should probably get those books first to start learning the ins and out of the 283 and basic engine knowledge.

Asylum thanks for the tips & info, I also enjoyed your site, your "Ugly Truck" project gave me lots of ideas and knowledge on truck restroration. Dale thanks for the postive feedback on 283's, I was thinking eventually I would have to upgrade to a bigger engine to get that kind of horse.

Once I finish some of the other parts of the truck & bloody up my knuckles some more, dual exaust will be going in . I'll be sure to keep you guys updated as I make improvements and advances in the project. I've learned a lot from this guys, anyone else who has some knowledge or tips they wan't to share, I'm all ears.

Thank You,
Nolan

double hump head and power pack are different. the power pack came on 283's and some 327's double hump head came on 327's manely. good luck sctrucker