Whats the difference in XXX and YYY on the block?

#7
These marking came into use with the 80's-90's 5.0 liter versions. XXX signifies a roller cam equiped HO (high output) motor (or Cobra)such as used in Mustangs, Lincolns, V8 Explorers ect. The XXX blocks used a roller cam with a lifter retaining tray and X shaped lifter lock downs. The XXX blocks are for more heavy duty applications too. I believe that the Y markings were used on non-roller cam motors such as used in police interceptor Crown Vics, Marquises, Town Cars ect. Variations of these markings probably help to keep track of different cam, block, and EFI intake design combonations. For example, truck 5.0's after about 94 had roller cams, but were still different from Mustang, Cobra and Explorer type HO 5.0's.

I found that somewhere...(im really not that smart)
 
#9
5.0 con-vert said:
These marking came into use with the 80's-90's 5.0 liter versions. XXX signifies a roller cam equiped HO (high output) motor (or Cobra)such as used in Mustangs, Lincolns, V8 Explorers ect. The XXX blocks used a roller cam with a lifter retaining tray and X shaped lifter lock downs. The XXX blocks are for more heavy duty applications too. I believe that the Y markings were used on non-roller cam motors such as used in police interceptor Crown Vics, Marquises, Town Cars ect. Variations of these markings probably help to keep track of different cam, block, and EFI intake design combonations. For example, truck 5.0's after about 94 had roller cams, but were still different from Mustang, Cobra and Explorer type HO 5.0's.

I found that somewhere...(im really not that smart)
Click to expand...

Then why are my '79 and '84 flat tappet blocks XXX blocks? This has been covered many times and the general consensus is, it doesn't mean jack. You can pop off the intake on just about anything and it's 6 one eway or a half dozen the other whether it has a xxx or a yyy cast in it.
 
#10
95GTAODE said:
Then why are my '79 and '84 flat tappet blocks XXX blocks? This has been covered many times and the general consensus is, it doesn't mean jack. You can pop off the intake on just about anything and it's 6 one eway or a half dozen the other whether it has a xxx or a yyy cast in it.
Click to expand...

I agree...like I said, I just found that online somewhere. It's probably nothing more than the casting line it came off of or somethin meaningless like that...but everyone loves a good :bs: story!
 
#11
the xxx doesnt mean mexican? thats wut i was thinking idk there has to be a difference in them for instance i notice that towards the back of my block in the lifter vally one of the holes for the lifters was cut a little lower so the dog bone sits alittle lower on that one than the rest... still tightended down snug but more of a space... idk i hope mines stronger than normal that would be a plus!
 
#14
Well, my old block out of my 1990 roller motor had YYY in the lifter valley, the one I have now which is flat tappet has XXX written on the lifter valley.

Oh yeah, I have the porno block, porno interior.... will this make the tires stick a little better?
 
#16
not sure but if it helps the motor that came out of my 91 GT had XXX- the one I put back in was out of a 91 lincoln had YYY, so i think XXX means orig. HO factory block but there is no difference betwen the two.
 
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