[DeTomaso] c & m blocks

[JDeRyke at aol.com]

In a message dated 8/9/10 12:21:04 PM, Thomas.Tornblom at hax.se writes:

> Aren't the engine mounts different?
> Most 400 blocks, and I guess the 351M, require a different bellhousing, 
> same as the big blocks.
> 
Absolutely correct, Thomas. I had one around for a few weeks out of a 
motorhome, with a split cylinder (separated an intake valve going up a hill; 
stock are the infamous 2 piece valves). The engine mounts in the 'M's are 
"unique"- different from all small, mediium and big blocks. The bellhousing has a 
big-block pattern except for the rare 400M with a dual bellhousing bolt 
pattern (I've only seen photos from Dan Jones' collection). The blocks are 1" 
taller on each side than a 351C, and use very long con-rods as a result. The 
higher block pushes the heads and headers up so the left one hits the Pantera 
fuel tank and both hit the rear springs so custom headers are needed. There 
are other detail differences, too. But the biggest obstacle is the cracking 
often found in the lifter galley in seasoned blocks: it will be a 
horizontal crack above the lifer bores, about 4"-6" long thru into the water jackets 
and unrepairable; the result of an entirely new core shift during casting. 
This was finally corrected in the mid-'70s but beware of early blocks. And 
none were thick-wall cylinders either so they still need sonic testing for 
cylinder core shift.   
A buildup can certainly be done- several have been in motorhead magazines 
recently but you will replace everything in & on the engine: as-stock 400 
cubic inches that put out 175 bhp w/2V-type open chamber heads, junk valves, 2 
bbl iron intake, unbaffled oil pans and no specific speed parts available 
(some 351C parts swap in). Found in low-revving station wagons, vans, 
motorhomes and the cheaper heavy trucks. FWIW they simply are not worth the effort 
when 460s are cheaper, stronger, easier to build to higher performance and 
easier to find a good one. 400Ms are cheap to buy 'cause no one wants them. 
Think of an ox rather than a racehorse....My 2¢- J DeRyke