What a great collection you have there Pat!
MYSTERY MOTOR & Z-11
- Thread starter Blk61409
- Start date
Thank you Pat!!
wristpin
Well Known Member
It's always Amazing to see rare engines. It's Stunning to see engines with a true rare history. The engines in your care are beyond historical rarity...they are one of a kind, impossible to recreate, living history. Thank you for all you do to keep these treasures alive.
Blk61,what year was the aluminum 283?Did it use the 461 casting aluminum heads that were to be used on the 60 FI corvette?The MM exhaust system was a work of art in an era of exotic factory exhaust systems,the only ones that were comparable visually were the chrysler max wedge and 64 track hemi.Did the MM use dripper valve covers,and did it literally use the Z-11 crank or was it a larger main journal like the later Mk.IV?Also do you know the CFM rating of the holley they used?Was it the first of the big 800-850's?I know ford was having them make 780's by then and chrysler used a 800-850 on the 64 track hemi.Just trying to make the MM not so mysterious to me.
wrench thanks for the link very informative,thats got to be the biggest alt. pulley I've ever seen bigger than the moroso, the brackets look 409ish completely different from mk IV.They did a nice job on the deep sump pan,very similar to how ford did their FE deep sump cut the sump off one pan where it turns vertical and then welded it onto another pan that they had just cut the very bottom off leaves just one weld bead versus adding a section like the aftermarket does.The pushrod guides have to be the most expensive ever made,chevrolet was not f*ing around with this motor.Doesn't appear to be a transistor distributor ,dual point?The thermostat housing shown looks like a 90's vintage piece with the 9 digit casting number starting with 140 and the GM logo.
Here goes....the 283
HEADS cast 6-24-59
Casting number 3772895
BLOCK, cast 3-4-59
MYSTERY MOTOR
Dripper valve covers-Yes
However to accommodate keeping the droppers and use the more efficient roller rockers we made a set of spacers to raise up the covers.
HEADERS
I totally agree!!
Bill Howell the engineer assigned to the MM told me they got 75 HP more out of the engine by just using these designed headers.
They still had to design them around the car, steering shaft clearance, oil filter, frame etc.
Note the less than desirable bends in the lower pipes. These are NOS pipes also!!
CRANKSHAFT
Yes, it is the exact same crank as the Z-11, same casting number as my Z-11. The lower end of the block is exactly the same as the 409/Z-11. The pan interchanges.
HOLLEY CARB
I have forgotten!!
Wrench's article might have it. I'll look it up if not found.
I actually have 3 carbs, 2 complete and one for parts.
Actually, the first time Chevrolet used the dreaded (ford) carburetor on any engine.
Jody will love this!!
If anyone stumbles across any Mystery Motor parts let me know.
They really are only useful in two ways, one to put on an engine, two, as a wall hanger!!
Pat
That happens when you get older Phil
Sometimes i have mystery clothes that arrive in our closet, Lynette assures me that they have been there a long time and i just dont take notice
Oh damn i fit that category compared to a lot of young whipper snappers on here
Steve
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You were called old by some asshole 
Pat,excellent pics literally engine porn that 283 must rank right up there with hens teeth,do the heads appear to based on power packs or double humps port and chamber wise?The dripper valve covers make you wonder if they were the result of exceptional attention to detail or lessons learned the hard way(I'd guess the latter).I'm guessing from the gasket modification that they do not share the bolt pattern of the mk.IV.What are the part/list numbers on the holley?I'm surprised holley didn't recommend the center pivot float LeMans bowls,maybe they intrude on the distributor,they do make for a pretty long carb. especially when you have distributor on the wrong end of the engine.
You may be right Don,I know they were around for 64 on the track hemi and the 427 ford nascar motors they were even in hot rod articles.But I was thinking they came out in very late 62 or 63 on shelby cobra 289's,that is how they got their nicknames but I could be wrong that may have been a later change on cobras.
