I might be buying a 1964 f-85 with a 425 in it from a 1966 toronado. I would like to do some performance modifications to it. I want to atleast do intake and headers. I have been doing some research and I believe that I'm going to want to get a dual plane intake. Is there one intake that stands out from the pack that isn't too expensive? I also notice dual carb intakes...how well do those work on a 425? It I haven't researched headers too much yet, any suggestions?
Once I get the intake and the headers, I will probably want to do a mild cam. Something that will improve performance and maintain a decent idle....nothing too aggressive.

If there are brands or websites to stay away from...please let me know. Thanks for any info you can give me.

 

As far as intakes go just stick with a single carb. The Edelbrock performer is a good runner for a mild engine like you are describing. Top that with a Holley 3310 vacuum secondary 750 carb and a set of Hooker 1-3/4" headers. For the cam I would look for something with about .500 lift and 220 degrees intake duration at .050 lift and a 110-112 lobe seperation angle. I would also use the Comp Cams cast roller tip rocker arms. This would be a nice budget setup IMO.

 

X2 for the recipe chad gave.
Also don't ignore your ignition system specifically the distributor and its timing events. Consider a properly curved HEI or MSD. All these improvements you desire need to work in unison. So before you start purchasing any parts know exactly what direction you want to go to achieve the desired end result. This will ensure all these expensive parts will play well together. Know the static compression of the engine before making any major improvements. A stock Toro 425 is 10.5:1 (I believe) which should yield somewhere around 165-175 psi. What ever the compression gauge says just make sure all 8 cylinders are with in 5%(ish) of each other. A leak down test would tell you how the rings and valve seal is. If it passes both of these tests then I would look an making improvements. If not rebuild/refreshing time.
The cam is the heart and will dictate intake, head, carb, header primary tube diameter and collector tube length, converter (if an auto) and rear gear etc... So pick a cam out first and it will dictate the rest. Edelbrock and others have "packages" which take the guess work out. After assembly super tuning the whole package is the next step.

 

Thanks for the info guys. The only thing I know about the carb that is currently on it is that its a 650 4 barrel edelbrock. Would this carb work or would I need to upgrade that too? I know that the whole system works in unison but I wouldn't have thought to start with the cam. Will the cam that was suggested have the awesome "lump" sound at idle? I like that sound, I just don't want it nearly stalling at idle. I know I sound novice but I do have wrench time...just not on anything with carbs. I know that the lump sound is due to the valve overlap.

 

I'd also recommend the Performer, but I'm not a big Holley fan. Qjet or Ebrock would be my choice for a primarily street-driven car. 650 is too small, go at least 750. The dual quad intakes are more for show than go, and I would only recommend the long-out-of-production Edelbrock 065 dual plane dual quad. I ran that on a 455 with two 500 CFM AFBs (basically the E-brock carbs) and it ran great, but a single 4bbl will probably perform better in the long run. I don't recommend the more common Offy single plane or dual port dual quad intakes. All they're good for is a basis for a fabricated blower intake.

 

Like you said, the lump lump sound comes from overlap. To get that you may need either more duration or a smaller LSA. My cam is 230/238 at .050 on a 110 LSA and it has a nice sound to it.

 

The 650 could be OK if set up properly (jets/rods & springs). The math says about 675 cfm for a 425 at 5500 max rpm. So its about right in the middle of a 650 & a 750. If it an AVS series they are great and IMO, simple to tune. Get a spring & rod kit from E-brock. Their tech line is very helpful & knowledgeable. So the 650 may work if set up right. Of course Im in favor of a properly tuned 750 Q-Jet. I believe the orignal carb on a 66 Toro was a 4MV (7026250) rated at 750.

 

Great info guys, thanks a lot. What kind of gains do you think I could get with the setups you guys suggested...ballpark?. I know there are variables in this guesstimate.

 

I agree with virtually everything here except that Holley, quick fuel, Proform carbs are good options when properly setup.
For a cam I'd do an Erson TQ40, 220/228@.050 with .504 lift. That would give you good power, a little lope and work with a stock valvetrain.
With the above pieces you'll make in the 375 range with great drive ability.

 

Isn't 375 what a 425 makes stock?

 

Yes but in a perfect world. This would be real world, and probably with a bit more midrange torque.