i just recently rebuilt my 351w. it is .030 over, and has a new rv cam. ever since the rebuild it just hasn't run right. it seems sluggish and it coughs and misses if you try to start out slow. and it is alot harder on gas now. once it's going good you can stomp on it and it will pick up real good but it still doesn't seem like it's revving high enough even when it's on the mat. just sitting there idleing it runs perfect. i just would like to know whre my timing should be set.

also the carb was rebuilt too so that might need adjusted

thanks

 

As an example my 302, with a lopey cam in it, has the initial timing set at 16 degrees along with 20 degrees centrifugal for a total of 36. Compression is 10.5 and have seen many articles suggesting 32-36 degrees, total, for such engines with performance cams. The difference in idle and vacuum between a standard 6-8 degrees and 16 degrees is dramatic to say the least. You sound as though your timing is retarded some.

You would have to pull the cam out of the distributor to see what you have inside. Hard to say since the 289 was set at 13L (26 degrees) by the factory while the 302 was set at 10L (20 degrees) by the factory. You would be one of those since I doubt they would have set a stock 351 at 15L or 18L inside. Let's assume 13L, or 26 degrees, so you could go at least 12 initial and then see how things run assuming the dizzy is right on the money in the block. Stock engines seem to ok with 38-42 total degrees but you have an RV cam so maybe we wouldn't go too high in that range. After that is set then adjust your idle mixture screws to give you your highest idle speed before touching the idle speed screw. If you have vacuum advance then make sure it is working correctly.

 

10 to 12 degrees whould be about right.

 

try the 302 firing order...........might have gotten a 302 cam...it's happens

try a Known good carb on it... one from a friends truck, car that runs good.

see what happens...

 

Please help me understand what you said. When you said 16 degrees initial, I am assuming 16 degrees with the vaccum disconnected and plugged. When you are measuring your total timing, is the vaccum advance connected? I'm running 8 degrees initial with the vaccum off and plugged, 32 total. It has a tendency for an occasional stumble but comes on real strong from about 1300 up to 5000. I'm running a Comp cam 493/500 and flat top forged pistons. Would like a quicker low end response but don't want to run so much timing I damage anything else, hence the conservative approach.

 

check this out read it all, I do it to every Duraspark I have used

http://www.reincarnation-automotive....ons_index.html

got some more stuff on it some where...........

 

Yes, 16 degrees with the vacuum line disconnected although the line pulls no vacuum at normal idle speeds. Total timing isn't measured so to speak. I take apart the centrifugal mechanism to see what it is set at, clean all the moving parts and lightly lube pivot points. The distributor cam inside the 302 has two slots labeled 10L and 15L and these are the two amounts I can choose for cetrifugal/internal advance if I want. They will give me 20 and 30 degrees respectively. There are also 13L and 18L cams in Ford distributors that can be swapped around. Since the car was set at 10L, or 20 degrees from the factory (very conservative), I left it there for the now modified engine. So I have 16 degrees initial + 20 degrees centrifugal for a total of 36 degrees. Now you mention 32 total which means 32-8= 24 centifugal. How, since I have yet to see a 12L distributor cam in a points Ford distributor sitting in my garage. Duraspark maybe. Is this by visual inspection or just estimation?

I see no reason why you couldn't try out 16 degrees initial since it looks like your cam is a little tammer than mine in lift and probably duration. Get rid of the heavy spring inside since there is no reason to limit full advance to be in by 3500 rpm. Might get it in by 3000 rpm with that one spring swapped out. As for low end response you won't see a lot of improvement since the cam, like mine, really doesn't hit it's stride until 2500-3000 rpm or so. My car isn't quick off the line, but if held in 1st and you reach 30 mph then bam off she goes. On the freeway going from 55 to 90 is effortless for the engine at a very fast pace. If I want low end I'll need to change the cam itself.

 

Is this carb or EFI? If carb, 2bbl or 4bbl? Specs of carb, please.


Pete