>Want to get a bit more power out of my Cleveland. At DVSFII, I had
>the car on the chassis dyno. The engine is a 40 over, balanced and
>blueprinted, keith black pistons about 9.3 to 1, performer 4V intake,
>arizona exhaust pipes,
Your cam specs are 214/224 @ 0.050" lift, 0.510"/0.536" lift, 112 LSA.
That's a fairly mild cam, equivalent in specs to the old Ford Motorsport
351C hydraulic flat tappet grind, though several others make a similar
cam. It's best suited to give a wide torque band with open chamber 4V
heads.
>On the dyno the car was running very lean. I believe that is was because
>the intake manifold gaskets where sucking air and
oil from the lifter
>valley. It was very obvious when I changed the gaskets.
The rubber intake manifold gasket end seals can be also be troublesome,
especially if the heads and/or intake have been milled. Many builders
toss the rubber seals and just lay down a bead of RTV. I don't like
this as I've seen too many engines with RTV bits clogging up pushrod
holes and
oil pick ups. I prefer to buy or make my own from cork. I
peen the block rails with a punch so the gasket won't squeeze out while
it's being torqued down. This also works well on valve cover and
oil pan
gaskets. Use Permatex 300 or a contact cement to hold the gaskets in
place. Don't use RTV, except in the corners of the end rails and even
there I prefer using the red-brown Permatex. Retain the turkey pan
unless the carb heat ports are blocked. The pan protects the oil from
splashing on the hot exhaust crossover port.
>The car made 323HP and 354 torque to the rear wheels through a toploader
>and jag rear. Torque curve was very broad and peaked at about 3500.
About what you'd expect for the cam and intake you have.
>HP peakes at about 5300 where it remained the same until 6100. By 6500
>it was down almost 50HP. This is where I think I can get more. I think
>the car is under carburated with a 600CFM vacuum secondary Holley.
>Looking for suggestions and experience on a larger carb for this package.
The peak is about where I'd expect it so the best you can hope for is
to make it hang one a bit longer. I'd suggest a Blue Thunder intake
and at least a 700DP to a 780CFM vacuum secondary carb.
>Also, I was wondering how much HP I would actually see by going to
>roller rockers.
Very little. There's some friction reduction but the usual horsepower
increase attributed to roller rockers are due to an increase in rocker
ratio but you're already at 1.73:1, not 1.5 (SBC) or 1.6 (SBF).
The best reason to run roller rockers is to prolong valve guide life.
A windage tray might free up a few horsepower for not too much money.
>They seem to be strong believers in the Australian 2v heads for the
>street.
I run them on one of my 351C's. They have their place but for a
Cobra I'd jump right to 4V heads, preferably with closed chambers.
2V heads flow about 210 CFM with a decent valve job. 4V's flow
closer to 290 CFM. With a bit of cleanup 300+ CFM is typical.
It takes quite a bit of portsing to get an Aussie 2V into the 250
to 260 CFM range.
>I, myself built a 400m with 4v quenced heads with spacer plates
>and an Edelbrock torquer and 750 Holley combo.
Those can be quite strong. I've got a couple of 400's stored away
myself, one with the rare small block bellhousing bolt pattern.
A Holley Strip Dominator will make a bunch more power than the Torker
on that engine if has a decent cam and compression.
>393 is the max they build clevelands.
Don't tell that to my 408C stroker (4" stroke, 4.030" bore, 6" rods).
Cleveland deck height is 9.2", so the math works out to:
piston pin height = deck height - (rod length + crank stroke/2)
= 9.2 - (6.0 + 4.0/2)
= 1.2 inches
331 and 347 cubic inch strokers are popular for 5.0L Ford V8's these days.
5.0L V8's have a deck height of 8.2", so plugging the pertinent values
into the formula yields:
deck height - (rod length + stroke/2) = pin height
8.2 - (5.4 + 3.4/2 ) = 1.100 inches
8.2 - (5.4 + 3.25/2 ) = 1.175 inches
so you can see the 1.2" pin height of my 408C stroker is better than the
popular 5.0L stroker kits.
>I believe I would recommend an Edelbrock Torker and a 650 Holley DP.
The Torker might gain a bit of power upstairs but there are better
intakes. The best dual plane is the Blue Thunder high rise and the
best single plane is the Strip Dominator. Given the mild cam and
compression, I'd opt for the Blue Thunder, for a stouter engine the
Strip Dominator.
>If you are going to build a 427 Cleveland, you are going to have to
>use an aftermarket block or a 400 block because cleveland block doesn't
>have enough deck height.
It can be done and I've laid hands on a 430 cube 351C but it was
a drag only motor (small journal rods, narrow ring pack) and isn't
recommended for the street. For the street, a 408C is a good
compromise.
>But try the 600 you have first on the Torker- it might surprise you.
>Performer is restrictive.
The Torker is considered a dog in Pantera and drag circles. The
Performer is okay for a heavy vehicle and automatic. 600 CFM is
too small. The stock 4300D carbs were 715 CFM. I run a 735 CFM
Holley on my Pantera and still pull down 20+ MPG on the highway.
>Compression ratio is also a little low for 4v heads also. These
>Clevelands like compression!
Yes. The best approach is flat top pistons and closed chamber
heads for a stock stroke engine.
>Try talking with the pantera crowd, they run that motor.
Yes we do :-)
Dan Jones
1974 DeTomaso Pantera L