351 CJ what actually is it? what can I do with it?

[scgamecock]

Hey guys this is a little premature since I have a lot to do before thinking about working on performance. What I wanted to do is get some advice and information as to how I can rebuild the 351 CJ and increase its performance.

- what makes the Cobra Jet 351 different from a regular Cleveland?

-How good are the stock heads?

-What should be done to the stock heads? It looks like one of the biggest mods is to put in screw in studs. This would allow valve adjustment and larger cam correct?

-Again a little premature but I will be looking for a good lumpy idle. What cams come to mind that would give me that and what would I have to do to make them work in the motor? My car is a 4 speed with the stock 323 gear but I do plan on changing to a taller gear. Solid lifter cams have always then my preference. I might think about roller this time depending on the overall cost to rebuild the motor.

What books or videos do you guys recommend?

For any of you old school guys that still remember Super Shops and Erson cams. My first Mach 1 was a 351 2 barrel. Not having a clue that I could not put a high flow 3 cam in the motor without changing to studs and adjustable rockers that did not end well. It sounded great during the first part of the break-in period. After it got warm it sheard off the spark plug in one of the cylinders and dropped two valves, cracked cylinder and piston.

At 16 I didn't know any better and trusted a guy that worked for a NASCAR team. He never said anything about valve to piston clearance. Needless to say I figured that out real quick. The guy just wanted the $300 that I was paying him. This lead to me having to sell my first Mach 1. I have built several big block Chevrolet on my own sense but just now returning to Fords and want to make sure I know what I'm doing this time.

Thanks!!

Wade

 

[barnett468]

.

wow, ok, a cobra jet may have 4 bolt mains and will have 4 barrel heads . . thats the main difference

you do not need screw on studs . . if you have 2v heads, yoou have aluminum bases below the rocker arms that should be changed to the 4v steel ones for performance cams.

if you have more than around .550 lift, you need different rockers because the stock ones will bind . yellow terra makes several levels of rockers.

if you want a decent rumble with some crackle, you need compression and at least a comp xe274h cam and loud mufflers like flowmaster single baffle series 10.

if you use this cam, you must have at least 3.50 gears and a 2000 rpm stall to make it accelerate at a decent rate.

if you want a smaller cam that still has a little rumble, you can use the comp xe268h with 3.43 gears and a 2000 rpm stall.

 

[73pony]

I think he has a 4 speed so that would open up his cam selection a little more.

 

[c9zx]

CJ is what ford called the 351C 4V in very late 1971, 1972, and some say early 1973 model years. The CJ heads are open chamber and the CJ cam is different than the 1971 351c 4V. The CJs used a 4300D carb and the 1971 4V used the 4300A. Valve sizes are the same for 1971, 1972, and some say very early 1973. Smaller valve sizes for 1973 and 1974.

There is a lot of potential with any 351C, especially any 4V.

Chuck