I know i am posting alot here but it seems every day i find a problem that i can not resolve.

Anyway, My 351w idles beautifuly but when the engine is under load beautiful turns to ugly.

While under load i lose 95% power and get bad backfire threw the carb. I have checked the timing and it is right on so i am suspecting fuel delevery. The filter is not clogged so i am suspecting the accel. pump. Does these symptoms sound like a accel. pump? I have also checked for vacuum leaks & Intake leaks with none found. I have also looked at the fuel PSI and i am getting 7 psi. is this right for a carb setup?

Any help appreciated!

Thanks!

 

Well at least it sounds like you have it running. What dizzy did you end up using? Initially it sounds like a timing issue. There can be a lot of ways it can be out of time. Did you check to make sure that the mark on the harmonic balancer is in the correct location? They can slip and there is no timing one using the marks. You would check that the number one piston is at the top of the stroke and then make sure the timing mark is in the right location. If it is, and you have a vacuum dizzy, where did you get the vacuum from? Have you tried to start and run the engine with the vacuum disconnected? I'd check these first before tearing into a carb....huh, what carb is one the engine and is it the right one? Usually a throttle pump will make one stumble on acceleration but not generally make it back fire thru the carb on an early model like yours. The pressure at 7 lbs sounds a little on the light side but I didn't look it up. I usually expect 8 lbs but that would not cause your issue. Light pressure on a carbed engine usually means the engine runs out of gas at high rpms- like my modded 390 used to do. And just how far did this engine get torn apart? From yer other posts it sounds like it was together but missing a few pieces. Did somebody tear this engine apart before you bought it and never got it back together?

 

Clogged catalytic converter or exhaust system?

Are you sure the plug wires are hooked up in the correct firing order?

 

I went to the local auto salvage yard and found a DSII Ignition with the vacuum dizzy, on TDC Comp. #1 piston is right on with the harmonic dampener. I did un-do the vacuum on the dizzy and plugged the line but same thing happened (no power & popping threw the carb with load) There isn't much missing anything just a few vacuum lines that wasn't hooked up but i hooked those up. The biggest thing missing is the eec computer.
The carb is a Holley 2 barrel don't know the model sorry.

When i got the truck it was a project truck, mostly everything is on it but un hooked but since the EEC is missing i bypassed all the sensors and hooked the vacuum lines up like on a earlier model without emissions. The only problem i have now is the no power and popping under load.

Also, if it helps i have the C6 tranny.

 

I took the cats off a week ago and i have checked the wires twice there on as follows.

1-3-7-2-6-5-4-8

 

I also forgot to mention i have a Motorcraft 2150 Carb but it needs some work, I have had it on the truck and it runs horrible with it.

 

Okay, it sounds like you have the dizzy in correctly and properly timed. I assume when you set the dizzy in the engine that it was on number 1 cylinder to fire when fully seated in the engine. If not, there's yer problem. How long has this engine sat? What oil are you using in it? If it has sat for a while, the valves might be sticking. The usual fix is to put a qt of ATF in the oil and it'll loosen the guides up a little. You can also use a 5w-20 oil if the ATF sounds a little radical for you....but it works. Other than the firing order being wrong is the only other timing issue that I can think of offhand.
The 2 barrel carb you have. What is it and about what size? Is this a carb with known history or are you guessing that it is a good carb? Have you put a vacuum gauge on it yet and if so, what did you get for vacuum and was the needle steady or pulsing?

 

Sounds like an ignition problem to me. I'd double check everything make sure the engine is exactly at #1 and all that. I've had times where I was sure I had it all right and it turned out I didnt. Bring it up to # 1 make sure the valves are closed on #1 they wont be if its on the exhaust stroke, Is the timing chain worn out? you can get a pretty good idea how stretched it is by moving the distributor around to much play and you might need a chain.

 

Yes, The dizzy is in right and is in time good too, I bought the truck from a old man who drove it alot so it didn't sit much. No valves are stuck, i took the valve covers off cause i had a leak and since i had them off i checked that. I am pretty sure the wires are on right i have them connected to # 1-3-7-2-6-5-4-8 pistons, Is that right for a 351w? Sorry but i don't have any info on the carb except it is a Holley 2 barrel and yes i am guessing it is good but i have no idea. No i haven't put a vacuum gauge on it as i do not own one.

 

I put a new OEM Timing chain on it about a month ago, If it will ever stop raining here in Ga i will double check the timing on #1. I have checked it like 3 times and it is right on.

 

how about the firing order sure you got it in the right rotation and all. I know its frustrating but it really sounds like an ignition deal to me. Like I said I've been there with similar issues more then once..

 

Making sure the valves are closed at TDC would also verify you have the chain on correctly and all..

 

If i am correct i think the firing order on a 351w is 1-3-7-2-6-5-4-8 going CCW right?

 

I think there closing completely on TDC cause i have loads of compression but i haven't tested Compression yet. How much PSI. should i have?

 

I dont know the psi you should have but I'm pretty sure anything over about 105 psi is good to run it. My mach I had about 108 when I got it an it ran ok. If I recall correcty 108 is about 7.5-1. It should run as low as 7-1 I think. Maybe even a bit less.