[dhow69camaro]

Just bought a new 69 Camaro. Engine was running, everything seemed ok. It did not have a tach in it and I was told that it had ben sitting for several years, running little. I didn't want to run it to hard Put aftermarket gauges in it so I could make sure that everything was running correctly before I ran the engine any more. Engine is a 350 out of a 74 passenger/truck. Stock throughout as far as I can tell. Edlebrock carb. When it hits about 3100 rpm, it just drops off and starts backfiring. Timing is set at 10 degrees advanced. Vacuum hose is a little dry rotted so I will change that tomorrow, if anything is open. It also smell like it is running rich. Any help would be greatly appreciated. I will do my own research as well, but I am a kid in a candy shop and want immediate gratification...

 

[154567]

you will have to clean carb of all old fuel, probably replace all gaskets. Replace all vacuum hoses. Pull top off of distributor, make sure centrifugal weights are free of rust and moving. Might as well replace the plugs and plug wires while at it. Smog era engine means terrible cam and equally terrible heads. Go thru it, clean it, tune it, and start from there. In other words, maiximize the potential of what you have, then plan your mods. If you want it to run, start saving up for a decent cam and better heads. Your need for instant gratification is going to need to be tempered with patience.

 

[NH69Z28RS]

Does it have old school points and condenser ignition, GM HEI, or aftermarket ignition?

Either way check ignition components to make sure ignition can keep up as rpm's increase.

If points, could be burned/pitted, condenser could be bad, ignition coil could be failing.

Any of the above causing misfiring at higher rpm's would make it smell rich due to unburned fuel.

 

[TJS69]

If it is an actual backfire through the carb or exhaust, it means it fired at the time a valve is open. I would suspect that the timing chain has jumped or that the cam has a flat lobe. Pull the valve covers and watch the rockers !

 

[dhow69camaro]

What should be the upper limit for this engine on horsepower with stock cam, intake, and heads, edelbrock 1405 (600cfm), headers to 2.5" glass pipes(taking these off asap), and a Delco-Remy distributor? What should I look at first for upgrades?

What should I look for on the carb to see if it needs a rebuild? Thanks for the help!

 

[TJS69]

We would need the numbers off the block and heads to get an idea of what stock was at that time. In 1969 the 350 SS was rated at 300 H.P. In a Camaro in 1974 the highest horsepower 350 was less than 200hp. The trucks were usually a little bit more on horse power.

We need the engine ID number that is located on a pad under the alternator just in front of the passenger side head.



The Head numbers are :

 

[154567]

What should be the upper limit for this engine on horsepower with stock cam, intake, and heads, edelbrock 1405 (600cfm), headers to 2.5" glass pipes(taking these off asap), and a Delco-Remy distributor? What should I look at first for upgrades?

What should I look for on the carb to see if it needs a rebuild? Thanks for the help!

Take the carb apart, clean all passages. Put back together using rebuild kit from Edelbrock. I told you what the first upgrades are, better heads and a cam matched to those heads. Honestly, you would be so much further ahead to ditch that 1974 boat anchor and go find a 5.3 LS engine out of a pickup truck and swap it in. They make stupid power with just a cam change and some head porting. You'll have over 400 fuel injected horsepower for about $1500-$2500. New good heads alone will cost you about $1200 complete. You don't want to do that, find a roller cam Vortec engine out of a late 90's pickup truck. Rebuild it or find a rebuilt short blockout of a Vortec, cost about $450-$700. Already has a roller cam. Put some good heads on it and a decent cam and you'll be making around 400 hp and 420 tq.

 

[67Rally]

Honestly, you would be so much further ahead to ditch that 1974 boat anchor and go find a 5.3 LS engine out of a pickup truck and swap it in. They make stupid power with just a cam change and some head porting. You'll have over 400 fuel injected horsepower for about $1500-$2500.

I'm all for the LS swap, but there's no way you're doing it for $1500-2500 with ported heads and a cam swap. Gonna need motor mounts, bellhousing, new headers, gaskets, head bolts, timing chain, exhaust work, wiring harness, dyno tune....

You don't want to do that, find a roller cam Vortec engine out of a late 90's pickup truck. Rebuild it or find a rebuilt short blockout of a Vortec, cost about $450-$700. Already has a roller cam. Put some good heads on it and a decent cam and you'll be making around 400 hp and 420 tq.

This I agree with.

 

[Everett#2390]

Good advice given, David, and welcome.
The engine should run all the way up to 5500 rpm without a hitch.
Delco-Remy dist, make sure the point set is in good shape and no carbon tracks inside the dist cap and on the rotor. Some of the older ign parts were made of Bakelite, aka, wood chips, and they did like to become a resistance path to ground or to other cylinders.
Change any hoses you have a question about it integrity and ensure no other vacuum leaks.
Stock camshaft should indicate a steady 18"-20" of vacuum at idle.
If backfiring through the carb, as suggested, could be a sticky intake valve.
To troubleshoot, you might rev up to backfiring mode, then disconnect one at a time, a spark plug wire and view results. The cylinder pulled and no b/fire, is the sticky valve.
Pull the valve cover and squirt some oil on the guide and see if it loosens up.

You might change/borrow a known carb jus to see if it does run better.

 

[154567]

I'm all for the LS swap, but there's no way you're doing it for $1500-2500 with ported heads and a cam swap. Gonna need motor mounts, bellhousing, new headers, gaskets, head bolts, timing chain, exhaust work, wiring harness, dyno tune....



This I agree with.

Brent,
You can pick up the 5.3 engine for stupid cheap. Here's one for $300.

I have a LM7(5.3L) engine, that I bought from a guy who owns a shop in Manteca, and need to sell it. The guy I bought it from removed the engine from a 2000 Yukon, to drop in a LQ9 engine, and stated that the engine was running when it was pulled out of the truck. I DO NOT KNOW HOW MANY MILES ARE ON THE ENGINE, but I removed the oil pan and the valve covers to inspect the engine, and everything looks really good. You can still see the the cross-hatch honing on the cylinder walls, and the engine turns freely. I am going to throw in a 2000 LS1 intake that I had to buy seperate. WHAT YOU SEE IS WHAT YOU GET. DOES NOT INCLUDE THE ENGINE STAND. FIRST $300 TAKES IT!! I need to get rid of this engine because I'm moving and don't have the space for it.

Junkyards are full of them. If I was starting over or had the 1974 engine the OP has, I would do exactly what's in this article. I never said you could do the swap for $1500 to $2500, I said you could do the engine for that. If I was the OP, I'd pick up the engine for cheap, swap it in, and save up for the mods in the story and do it in stages. So much further ahead than working with the non-original engine that came in his car. And a lot more fun.

 

[DenRS]

I bet you need to clean the needle and seat I the carb. Doesn't take to much dirt to flood and the car will run like crap with no power, bucking, popping etc. if the carb checks out I would still do a tune up. If the car sat for years drain the fuel and put new gas in.

 

[dhow69camaro]

Update.... Finally took the distributor apart to take a look at the points, etc.... Original Delco Remy, top mounted coil HEI distributor has a small contact point from the coil to the rotor. It had broken off! Surprised it would run at all.

Pulled it out, replaced it with a MSD e-curve. Still was acting up. Pulled the plugs and they looked horrendous. Replaced and put wires in as well.

Still trying to figure out the e-curve, and I am still getting some backfire, but I can get it up to about 4800RPM now. I plan on rebuilding the edelbrock 1405 carb. Fuel lines have been replaced and new gas.

There is a small amount of liquid that seems to build up on the intake manifold bolt, driver's side of the carb. Doesn't smell like gas, but not positive. Thoughts? It almost looks like it is coming up through the bolt threads.

Thanks for the help!!!!