How bad have I screwed up, and how do I fix it?

[Anonymous]

I few years back I built my 200 from the block up, bone stock. regrind cam, all new pistons, turned crank, etc. It's a 65 mustang. I've since then added clifford dual headers, and flowmaster mufflers. 2 and 1/2"s before the muffler then 2 and 1/4"s after the mufflers. Port divider installed. I know it's overscavenging. Then I kept the stock 65 distributor w/ vacuum advance, but added the pertronix and hotter coil from mustangs unlimited. Then I got a 32/36 weber and bolted it on. Unknown jet size, just stuck it on the engine and went. The car has a new auto transmission as well. I know I should adjust the timing properly. I test drove it, and would accelerate hard and keep advancing until slight knock, then backed off. Basiclly as advanced as I could go without a knock under hard accelaeration. Now for the problem(s). The car starts and runs awesome, idles fine, and drives like a dream BUT - I read a bone stock car from road and track magazine in the 1960's had my car 0 - 60 at 15.2 seconds. With all my mods, I'm getting 17.8 at best!. Aside from ordering the Falcon handbook - the check is already on it's way, what can I do to correct this? Are the pipes too big and killing me? Is the jet size from clifford (weber) typically too small? How do I properly jet, and more inportantly how do I tune the carb? My rear valance is always turning black from running rich. Is my stock distributor killing me? Can I install a mechanical advance Mallory distributor and be better off? I need some numbers for timing advance, and jet size so I can bring them to a REAL mechanic instead of me continuing to hack my car up any further! What else can I do to fix this short of ripping the cam out, and replacing a new expensive exhaust system with another new exhaust system? I'm a backyard tinkerer, and ham and egger. Looking to tune the engine and get the most out of this situation/combination. I found this site a while back - but too late. Please help, thanks and Happy New Year

 

[falcon kyle]

Back yard novice also. Do know with the stock cam, weber and 65 log head. You are not getting enough air. Severial of the real knowledgable folks on this site can give you lots of ideas. Just hang in there.

 

[strat1960s]

I agree, that if you are running the stock log head, you may not be getting enough air. Have you considered and OZ or Arg head. Both heads with dramatically increase the air flow into your motor.
Now, on the question of your carb. I have just recently gone through some of the same things you are dealing with. Webers are a strange breed. I was running a little rich after my engine was rebuilt leaving me with several options to correct the condition.
1. You can go with a smaller main jet
2. You can go with a bigger air correcter jet
3. Advance your timing (sounds like you already have tried that)
4. Any combination of the above
Having said that, I'll tell you what the owner of 5 Star Engines (shop that rebuilt my motor) told me. "This is your motor and no one should be messing around with the timing and tuning but you." I admit I do not know all there is to know about carbs, but I am learning as I go. Read up on your carb. Redline Weber has a web page on how to tune and jet your carb. http://www.webercarbsdirect.com/home
Also, buy a munal for your carb. Haynes Publications # 10240 covers most of the Weber carbs out there.
I know this may not be the answer to your questions, but it will at least help steer you in the right direction.
Keep us posted.

Ted

 

[CZLN6]

Howdy Matt and All:

Matt- you said you have a "reground cam". Is this a stock specification cam or what?

Know that your distributor is a part of your performance problem and will always be. It is a vacuum only advance distributor, but in addition it is designed to work with the Spark Control Valve that is part of the stock '65 Autolite 1100 carb that you are no longer using. If you hook the vacuum advance line from this distirbutor you will have very high advance at an idle and cruise (high Vacuum), and none under acceleration (low Vacuum). The solution is to upgrade to a '68 or later distributor, which utilizes both centrifugal and vacuum advance, and your Petronix Ignitor may be transferred, depending on shaft configuration. The other option is to adapt the later DuraSpark II electronic system to your '65 engine.

Once this is done, I highly recommend tuning the timing with a timing light. If you don't know where you are you won't know where you're going or how to get back to where you were.

Be assured that the exhaust system is not the problem. Nor is the head limiting you to at least above stock performance. We've seen significant performance increases with just bolting on an 1101 carb, so the '65 head is not the problem either.

Clearly, the carb needs some sorting out. Ted has given you some good advice. Learn your system and learn to tune it to it's potential. The Holley/Weber is capable of great performance.

Learn, and enjoy the journey.

Adios, David