the latest adventure.

[66StangGuy]

i am wrighting this because i am trying to help out anyone who changes the heads on their mustang.

so here it began. at work fixing a mt street tire for a blown 5.0. when the guy says hey is that your car. and he points at my mustang. long story short he tells me that he has heads for my car he is trying to sell. so i got them for 350. they are world castings winsor sr's 200cc intake runners 2.02 intake 1.60 exhaust. they came with screw in studs and erson cams 1.6 roller rockers. so on a day off i tear it apart and install the heads. adjust the rockers and off i went. took it down the street and just bairly taped the pedal and my ride scared the livin stuff out of me. she went sideways and just threw the rpms to 5500 in a flash. my old heads must have really ben restrivtive. the only thing holding my motor back now was cam and the intake ports on my performer are a little small compared to the heads. anyway driving my car to work. about 3 blocks from work at a red light i hear the rockers starting to tap. then suddenly the car starts to shake and the motor sound like it dropped a cylinder. so i pull over and check it out. i had my tools with me still since i was still adjusting the rockers. so i pull the valve cover off the pasenger side and find that 2 rockers had completely come off. first and third cylinder. so i was trying to put them back on when i noticed the pushrod for the first cylinder was not seating right. the pushrod was not bent. so with no other tools or ideas i had my baby towed by AAA to my work (Pepboys) later found out that because the rocker came off the cam pushed the lifter out of the block and was just sitting up top. so pulled the intake and fixed it. it just slipped back in. put it all back together and put locktite on the adjusters for the rockers. now she runs great. now i just have to find the sweet spot in the timing. and jet the carb.


here are a few questions that are pondering me.

the heads i took off my car are 69 302's stamped with B in the center. (for sale by the way)

are they boss 302's? from what i know a boss 302 is a 302 block with 351 heads. right??

the valves were white and my plugs look new.
am i running lean?
i always thought i was running rich.

also noticed on my pistons that right were the spark plug sits above the piston there is a little discoloration. what would cause this? bad timing curve or what?

thanks for reading this long thing and i hope that anyone who puts on new heads remembers to use locktite on the rocker adjusters. dont do what i did. thanks for any replys to my questions.

[69fastback]

The boss heads have canted valves. They where not 351 heads. If they have canted valves then they are boss heads. 351 clevelands came out with canted valves in 1970. A boss 302 is also a 4 bolt main block regular 302 blocks aren't. A boss also has a stronger crank.

As for your other questions i can't answer i am not very good at tunning a car. I do know that if your car is running really rich you can smell gas on the spark plugs.

[Rev]

You will have to do a full throttle run for 1/8-1/4 mile and then shnt off the ignition and coast to a stop in neutral (with new or good plugs). Then pull the plugs for a reading, I make a template out of cardboard with a hole numbered for each cylinder, so as to keep up with the individual cylinders.

Now with the plugs in the template, note the color of the INSULATOR. Not the ground strap or any other part of the plug. Tan is ideal, Gray is still OK. Dark brown is somewhat rich, and black is way to rich. Light white is too lean.

These guidelines only pertain to wide open throttle. Part throttle settings are another determimination.

Rev

[rbohm]

the heads i took off my car are 69 302's stamped with B in the center. (for sale by the way)

are they boss 302's? from what i know a boss 302 is a 302 block with 351 heads. right??
-------------------------

your stock heads are likely not boss heads. as was stated the boss heads have canted valves and very large ports.

the 351c 4v heads and the boss 302 heads are very similar. in fact the basic design is the same, just a couple of changes in the routing of the cooling system passages.
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the valves were white and my plugs look new.
am i running lean?
i always thought i was running rich.

also noticed on my pistons that right were the spark plug sits above the piston there is a little discoloration. what would cause this? bad timing curve or what?
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remember the valves and the area direclty below the plug are the hottest spots in the combustion chamber. what you are seeing is actually burnt carbon deposits. it is normal. plugs should be light tan to a medium brown in color for normal operation. i hate to sound contradictory, but white insulators can be either a rich or lean mix. usually if lean they will have a light discoloration to them. if rich, and the mix will realllly rich, they will be pure white as the fuel is washing the deposits off the plug. if the engine is that rich, you will have drivability problems, like hard starting, flooding, no power etc. so it sounds like you are running lean.
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[66StangGuy]

thanks for your reply.
i doubted that the heads i had were boss but i had to ask. what else would this b code mean? i know the intake side ports are faily large but the exhaust are quite small. What do you mean exactly by canted valves? as far as the lean condition. today i ordered #66 jets for my holley. ill see if it picks up a little now that i have some fuel to burn. thanks again for your reply.

[rbohm]

ok if you look at the valves, and they are all in a line, you have a windsor type head. the b is likely a version number for the mold. now if you look at the head and the intake valves are in one line and the exhaust valves in another, then you have a cleveland type head. if the intake mounting surface has passages in it for coolant flow at the ends on the head, then you have a boss 302 head.

[66StangGuy]

the heads have ports for coolant in the front and back. and i think they are windsor type. whats the value on this.

[rbohm]

in good shape about $100-150 bucks. they are not worth a great deal, but you might get more on ebay if you write the ad right.

[gofastmercury]

Have you looked into why the lifter would pop out? I would guess you floated a valve. Maybe it would be a good idea to get new springs as cheap insurance. Also are you running guide plates? You need to.

[66StangGuy]

the lifter came out because i have erson cams roller rockers and the locks on them SUCK. so the lifter fell off and because there is nothing holding the pushrod down when the cam lobe came around it just poped it out of place. and yes im running guide plates. next paycheck im going to order comp cams roller tip rockers and already bouht new pushrods. order my special header spark plugs and ordered my new jets for my holley. so everything is in the mail and as soon as it all gets here im going to put it on....think are starting to come together now.

[Rev]

That happened to me also when I put in Comp Cams Magnum roller tip rockers some years ago. I used Pioneer poly-locks to hold the adjustment. After adjusting the lash for the hydraulic cam, I just tightened down the allen screw with an allen wrench. I had been cautioned by my machine shop guru not to "munch down" really hard on the adjusting nuts with a socket wrench or risk twisting off the "coke bottle" studs that I had at the time.

To make a long story shorter, the locking allen screws came loose allowing the push rods to come out. This all happened while blowing the doors off an early Camaro on the highway. These Camaro guys had a good laugh as they finally caught up and passed as my engine sputtered.

Moral is, after adjusting those poly locks, come back with a socket wrench give a modest torque to the poly-lock adjusting nuts, no matter what the brand, in order to set them tight.

Rev

[gofastmercury]

Funny how no one tells you the little details. I had to learn the hard way with poly locks too. You can't just tighten the set screw, you need to give the whole thing a turn as you hold the screw, checking the lash as you go. It should never back out then.