SK = "sketch"
XE = "experimental engineering"
ASK = on documents it usually meant "assemble sketch ######" on actual parts it may have meant "advanced sketch ( prototype)"
XH= UNKNOWN
RX= possibly research prototype


-XE 93532 "david pearson block " 9.2 deck 351 WINDSOR 4 bolt mains on center 3 caps # cast in 100 % certainty source "blizzards attic "
-XE 121643 427 cammer block , painted # , 100% certainty
-XE 143079 - tunnel port 302 rocker shaft stand , etched ,100% certainty
-XE 143081 - tunnel port 302 rocker shaft spacer , etched , 100% certainty.
-XE 146476 gilmer pulley for boss 429 oil pump ( dry sump front half of pan) # is unverified
-XE 146762 boss 429 oil pan front section which contains a sump pump , # has not been verified
-XE 148003 boss 429 dual gear oil pump housing # is unverified
-XE 148826 boss 429 dual gear oil pump lid ,steel, # is unverified
-XE 192540 "australian " cleveland block , cast in , heavy webs 100% certainty.
various sources this is one of the most famous and well known of perhaps all xe part numbers
-XE 193476 spreadbore 4 barrel intake to fit 400 ford "police interceptor " package 2v port sizes # cast in 100% certainty.
-XE 193477 egr valve ,stamped in ink 100% certainty ,sub assembly of part above.
-XE 193478 EGR valve for 400 4v intake cast in 100% certainty
-XE ??424?? shaft rocker tunnel port 302 head , cast in , 0% certainty on the whole #
-SK 24520 427 cammer piston , stamped in ink , 100% certainty
-SK-31635 427 ford head , cast in , 100% certainty
source: NHRA
-SK-35369 427 ford head , cast in , 100% certainty
-SK 37080 tunnel port FE head as was used on lemans winning GT40's 100% certainty on number which was cast in source dove performance
-SK 41742 aluminum 3 2 bbl intake manifold to suit 429 ford number cast in 100% certainty
-SK 42157 68 tunnel port FE can am block which was used on RX 402 can am project 100% certainty ,source dove performance
-SK 42478 494 can am block , # is cast in block , not certain of the last number it could also be a 3 instead of an 8
-SK 42617 aluminum cleveland "can-am" block siamese bores , steel main caps , cast october 1968
-SK 46368 S.A. XH 10117 single plane ,dominator flange , D port , aluminum intake for boss 429 , cast by buddy bar ,100% certainty on # which is cast in.
-SK 48991 : cleveland rods made on doae forging machine ,specially heat treated , or shotpeened , or both , could also be a different material than 1041H .has 7/16 bolts like trans am boss 302 rods with the same fastener , which is splined. fastener requires an allen "super tork" socket mac tools sells a socket which is very close but not identical. the super tork has been out of production for some time.
-ASK-6866 steel main caps for ASK-6878 block , dowelled ,100% certainty on #
source : personal collection (joe)
-ASK-6867 steel main caps for ASK-6878 block similar to ones used on SK42617 aluminum can-am block, cast in 100% certainty
-ASK-6878 siamese bore cleveland block ,cast iron,heavier main webs than common cleveland blocks but not solid like the xe-192540 , additional water passage tapped and plugged on drivers side , screw in core plugs ,uses dry deck heads , steel main bearing caps on 1-4 not 5, 100% certainty on # also hand stamped ASK6877ASSY and ASK6878$4 ,meaning it was the fourth such prototype, cast august 1968
-ASK-7499 iron, siamese bore cleveland block webbing like typical cleveland block ,dowelled 4 bolt main caps. 100% certainty on # had unfinished 2.5 diameter main journals
-XH10089 : forged steel cleveland crank 100% certainty on # dan jones personal collection.
-XH 10117 S.A. SK 46368 boss 429 ,single plane ,D port aluminum intake , dominator flange, cast by buddy bar, 100% certainty on # which is cast in.

I didn't find any other shafts in the 424xx range, so XE42437 is likely correct. From a private collection which has asked that only limited samples be posted:





Shoe.

i have a tunnel port head that has a sk36228 stamped on it. there are no casting numbers. i was directed here by an fe sight. what is this? i know that it is an fe head, but is this anything special?

you'll get more questions than answers about these one off sk/xe part numbers ! we're no experts here .
What you have is a later development than any of the 427 heads we have listed thus far .

Tell us what you can about these heads , specifically how they differ from other tunnel port heads (as far as you can tell) sometimes their is only ONE REMAINING EXAMPLE of an sk/ask/xe part and no existing records in anybodies collection of ford logbooks that pertain too the parts themselves .

So tell us what you can and we'll go from there ! Sadly we may not go very far....

you want to know what is different? as far as i can tell it is cast much thinner than my c7-k head.i sonic checked the deck and its much thinner and has not been milled as much. the ports are either cast better or someone ported them. the knot that is just on the top of the exhaust valve is gone. the short turn on the intake is rounded then my c7.what i wanted to know is : any ideas on the head and why were sk heads made? if you want any info email me directly.

ford spent a ton of money in research and development making parts that were intended to be an improvement of existing designs, or complete redesigns, or completely new
altogether !