DeTomaso Mailing List: May 99, Message #111

Hi Dan and company:
All I can say is "GREAT"! You, I and the rest of us cat-heads realize a good
engine when we have one. Of course, that will make the rest of the MM
readers *think* that the Cleveland is a bunch of trash, bypassing this
treasure on the way to making junkyard pulls. That will preserve the
remaining supplies of 351C's available for us Clev-ophiles for many more
years to come. Cal #????

> -----Original Message-----
> From:	Daniel Jones [SMTP:djones2@mdc.com]
> Sent:	Wednesday, May 05, 1999 12:12 PM
> To:	Multiple recipients of list
> Subject:	351C versus 351W
> 
> Anyone see the 351C versus 351W article in the May issue of Mustang 
> Monthly?  It held some promise but they managed to muck it up by not
> knowing how to build a Cleveland.  While the 351W engine tested is a 
> reasonable selection of parts (essentially an Edelbrock Performer RPM 
> package with a bigger hydraulic roller cam), the Cleveland engine is 
> not.  They saddled the 351C with a low rise Edelbrock Performer intake 
> manifold but allowed the 351W to use a high rise Performer RPM.  A 
> Weiand Xcelerator would have been a much better comparison.  They chose 
> Aussie closed chamber 2V heads but use dished pistons (from what I can 
> gather from the pictures - no compression ratio is given), ruining 
> the quench effect which is the whole reason for using the Aussie heads.  
> Then they cam it all wrong.  The hydraulic roller cam specs out at 246/256
> 
> degrees duration @ 0.050" lift, 0.560"/0.585" lift and an LSA of 108 
> degrees.  That's way more cam than the intake and compression can 
> support.  Furthermore, the big lift is wasted on the 2V Aussie heads, 
> which start leveling off after 0.500" or so.  The cam also has a wide 
> dual pattern meant to crutch up a 4V head's poor intake-to-exhaust 
> flow ratio.  With an excellent exhaust port, 2V heads have a good flow 
> ratio and don't need a wide dual pattern.  Given that they chose to 
> install 4V valves, the heavy hydraulic roller lifters will probably 
> limit rpm to 6200 rpm or so.  I also question whether or not the 4V 
> valves do anything for flow without extensive porting.  No dimensions
> are given but they state the the headers are different.  No information
> is given on carb calibration or ignition curve but they do state an 
> Edelbrock 700 cfm carb was used.  I assume they meant 750 cfm, since 
> Edelbrock doesn't make a 700 cfm version.  They also only made one 
> pull per engine.  No tuning whatsoever but they claim they will make
> more runs in a later issue.
> 
> Even with all the mismatch, the Cleveland was able to make within 6 hp 
> of the Windsor if the numbers are to be believed.  However, if you look 
> at numbers printed:
> 
>              351C     351W
>    RPM      HP  TQ   HP  TQ
>    4500     348 410  373 409 
>    5000     380 389  390 369
>    5500     384 357  386 320
>    6000     376 319  366 266
> 
> they show the Cleveland making more torque at every point above 4000
> rpm but making less power.  Last time I checked that was impossible
> since horsepower is a direct function of torque and rpm.  Damn magazines.
> 
> FWIW, the relationship between torque and horsepowe can be expressed as:
> 
>    HP = (TQ*2.0*PI*RPM)/33000.0
> or
>    TQ = (33000.0*HP)/(2.0*PI*RPM)
>  
> where:
>  
>    TQ  = torque in ft-lbs
>    HP  = power in horsepower
>    RPM = engine speed in revolutions per minute
>    PI  = the mathematical constant PI (approximately 3.141592654)
>    Note: 33000 = conversion factor (550 ft-lbs/sec * 60 sec/min)
> 
> They also instruct the reader to use a "copious line of of RTV" instead 
> of the rubber end seals.  While I don't like the rubber seals either,
> loading it up with RTV is bad too.  When you torque down the manifold,
> the RTV has to go someplace, most likely into the oil supply so it can
> stop up the lifters or pickup.  Cork gaskets, a peened surface, and some 
> contact cement or gasket sealer is the way to go. 
> 
> I question their selection of parts as well.  The Windsor was totally
> aftermarket - SVO crank and block, custom pistons and rods, etc.  All
> for a motor that peaks at 5000 rpm.  There's a bunch of other stuff 
> wrong with the article but the above will do for starters. 
> 
> Dan Jones