ENGINE REBUILD

Canary
I'm not at all clear as to what you are trying to determine. There are some extremely knowledgeable people on the web site, but I think you have to be a lot more specific as to what you are shooting for to get any valid assistance. What do you want the car to do when its finished?

Bore, stroke, decked, cam specs, type of pistons, compression ratio, ignition, distributor,magnafluxed, sonic tested for bore shift, etc, etc.

Good Luck

OLD AND SLOW
JUST TRYING TO GET A LITTLE INPUT ON WHAT OTHER PANTERA OWNERS ARE USING
STARTED WITH A PRETTY MUCH STOCK PANTERA WITH COOLING UPDATES THAT WAS USING THE 800 DOUBLE PUMPER SREADBORE AND STRANGE OFFY INTAKE WITH A DIVIDER IN THE INTAKE PORT
CHANGED TO CLOSED CHAMBER HEADS WITH STOCK PISTONS AND BORE AND AM IN THE PROCESS OF INSTALLING THE .614/631 CAM. HAD THE VALVES CHANGED TO SINGLE GROOVE WITH THE MATCHING SPRINGS SPARK IS PROVIDED FROM A TWO WIRE MSD DISTR. AND BLASTER 2 COIL
HAVE SEEN SEVERAL TECH ARTICLES ON WHICH INTAKES TO USE BUT HAVE BEEN UNABLE TO FIND "THE RIGHT ONE" JUST WANT THE ENGINE TO REV A LITTLE HIGHER MAYBE A 6500 SHIFT
APPRECIATE ANY SUGGESTIONS THAT YOU CAN GIVE IN ANY AREA. JOHN

Thats a pretty healthy cam for a street engine; don't expect much gas mileage! I'd be careful using a Holley spreadbore carb, as many were emissions-calibrated Rochester replacements from the early '80s. In my experience, one cannot get the mixture rich enough in these units to support the cam you're describing, so the engine may run dangerously lean & not make much power. I recommend a dyno run, with a knowlegable carb guy to set this combo up properly.

JACK
HOLLEY CARB IS A LIST 6213 800 CFM DOUBLE PUMPER WAS ON CAR WHEN I PURCHASED
DYNO SESSIONS SOUNDS LIKE A GOOD IDEA
HAVE YOU EVER HEARD OF ANYBODY RUNNING
AN OFFENHAUSER SPREADBORE INTAKE WITH A
DIVIDER IN THE INTAKE WITH THE PRIMARIES
FEEDING THE TOP OF THE PORT AND THEN THE SECONDARIES FEEDING THE BOTTOM? INTAKE AND CARB SETUP WORKED VERY WELL WITH A 500 LIFT CAM

JACK
WOULD YOU RUN A TORKER INTAKE OR WEILAND
XCELERATOR INTAKE? SHOULD I REPLACE THE 6213
WITH A 4780 800 DOUBLE PUMPER OR TRY A 4781
850 DOUBLE PUMPER? HAVE BEEN LOOKING FOR A STRIP DOMINATOR INTAKE BUT SO FAR NO LUCK.
THANKS

If the Offy intake is an open-plenum, the partial divider thing is a trick to get a little more mixture into the manifold runners. Be careful- pulsations in the plenum are strong at higher engine speeds. I had such a divider crack, falling into an intake runner & jam against the valve guide. No engine damage- I was just lucky, I guess. My opinion- an 800 2-pumper is too much carb for anything but drag racing or top-end runs. The spreadbore sounds OK if its set up properly but I'd suggest if you find it too difficult to dial in, to try a 700 cfm conventional Holley, Demon or the like. Some guys are successfully running the Edelbrock/Carter carb which is a tunable spreadbore, but their cams are less serious than yours.

The Offy intake you are describing is the Dual Port. The dual port design
has the runners split into top and bottom sections, with the plenum split
fore-and-aft (rather than the usual side-to-side). It's essentially two
single plane intakes, stacked on top of each other. The primaries feed
the longer path lower runners and the secondaries feed the shorter path
upper runners. When cruising, the manifold operates on the smaller area,
longer path, runners. This provides high velocity flow for good fuel
economy and throttle response. Under high demand, the secondaries open
and provide additional flow through the larger top runner portion. It's
an interesting approach but the packaging required to fit within a carb
intake envelope does compromise the design somewhat. By reputation, it's
a good fuel economy, low end response intake but it is not a high power
or high RPM design. It is a terrible match with your .614"/.631" solid
lifter cam. That sort of cam requires a Holley Strip Dominator single
plane or at least a Blue Thunder high rise dual plane.

>Would you run a torker intake or weiand xcelerator intake?

I don't care for either of those intakes on the 4V heads, though I do
like the 2V Weiand Xcelerator for 2V heads. The Holley Strip Dominator
is the best intake for the sort of cam you're running.

>should i replace the 6213 with a 4780 800 double pumper or try a
>4781 850 double pumper

You might look at the tuner type carbs which flow more CFM for a
given bore size. Holley has the HP Series based on 750 carbs that
flow closer to 830 CFM. Demon makes similar carbs and their are
a number of tuners that do similar things to standard Holleys.

With a single plane intake, you'll want a carb with annular booster
venturis as they work better with low vacuum signals.

If you want to be differnt, the Predator variable venturi carb (make
sure you get the street version with idle circuit) works very well.
A friend runs one on a 377 cube stroke Cleveland and the Predator
mounted on a Holley Strip Dominator was better across the RPM band
(even down low) than a spreadbore Holley on a heavily ported Offy
Dual Port intake. The only problem is the Predator is a very tall
carb.

>Have been looking for a strip dominator intake but so far no luck.

Keep looking. They pop up on Ebay from time to time. Holley was
supposed to reintroduce it and have the tooling but Holley is in
serious financial trouble so the future is unclear.

Dan Jones

APPRECIATE ALL THE INPUT WILL KEEP YOU POSTED ON WHICH INTAKE AND CARB. COMBO WORKS WITH MY CAM. HAVE A NEW BIGGS 780 VAC. SEC.DYNOED FOR A 650 HP ENGINE MAY TRY IF THE SPREADBORE DOES NOT WORK. WILL KEEP LOOKING FOR A STRIP DOM. INTAKE IF YOU HAPPEN TO SEE ONE EMAIL ME CANARYPANTERA@AOL.COM