[DeTomaso] Questions on 4v heads

Sean Korb spkorb at gmail.com
Sun Oct 24 22:44:59 EDT 2010


I have to side with Jack on this.  I want to emphasize that if you are
using stock valves (or 40 year old valves and springs) please stop and
consider having your heads done.  The job isn't too involved and if
you care about your engine block, don't put it on a dyno again until
after you're done.

My engine is about like yours, #1382 with quench heads, Performer
manifold but 750CFM carburetor and exhaust that last had baffles in
the Nixon administration.  I pulled about 250HP on the dyno so not too
far off, but I bent two pushrods.  That's just a breath away from
pushing a piston out the side of my block.  In fact, when I did the
head swap (another set of 4V quench heads) I saw distinct impressions
of the valves where they had sat on the pistons briefly.

Right now, I'm only puttering to and from shows, and what I have is
more than enough, but I do have a spare engine with some speed parts
ready to go in when I settle on a cam/distributor solution (kind of
waiting for a zero maintenance roller cam to fall in my lap).
Suspension bushings come first, though.

I think it's most important to figure out what you want to do with the
car before you commit to a build.  If you want to go 180MPH, there's
some options, but you probably won;t have a good time with that motor
on the street in stop and go 20MPH traffic if you want to parade a
bit.  If you want dyno bragging rights you can be more extreme but
maybe lose durability and reliability.  What if you want to blow away
that pesky Diablo?  Then you need to select boost or cubes or both.

>From the numbers, it looks like Mike Drew has found a pretty good
balance with a well engineered parts matched stroker.  I hope it is
just as reliable as a stock-ish motor but I bet his gas mileage sucks.
 Of course, gas mileage is probably not on the priority list for
Pantera owners ;)

sean

-- 
Sean Korb spkorb at spkorb.org http://www.spkorb.org
'65,'68 Mustangs,'68 Cougar,'78 R100/7,'60 Metro,'59 A35,'71 Pantera #1382
"The more you drive, the less intelligent you get" --Miller
"Computers are useless.  They can only give you answers." -P. Picasso



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