Some basics of Cleveland building (in no particular order)
by Dan Jones:

- Use single piece stainless steel valves with single groove keepers. Valve 
train failure is the number one failure mode for a Cleveland. The stock 
valves are two piece with loose fitting multi-groove keepers. If they don't 
slip out of the keeper, they'll pop the head off. 

- Keep the overbore to a minumum and don't exceed 0.030" without sonic checking.

- Don't use the rubber intake manifold gasket end seals. Buy or make your 
own from cork. I peen the block rails with a punch so the gasket won't 
squeeze out while you're torquing it down. This also works well on valve
cover gaskets. Use Permatex 300 or a contact cement. 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.

- If you retain the stock rocker arms, make sure you use the steel 4V sled 
fulcrums. The 2V fulcrums are aluminum and come apart under load. Also, 
there are two types of stock rocker arms (lugged and unlugged) and one of 
them (I forget which) has pushrod to rocker arm clearance problems with 
high lift cams. Given the high lift of the typical Cleveland performance 
cam, roller rocker arms are a good investment for increased valve guide 
life. You may have some clearance issues with roller rockers and the valve 
covers. If your valve covers are equipped with drip rails (as Boss/HO cast 
aluminum and some factory steel valve covers were), you will have to remove 
them or bend them out of the way. You may also have to clearance the rockers 
arms near the oil filler and PCV baffles. Use the real FoMoCo rubber valve 
cover grommets. The repos just don't seam to fit right. Fel-Pro makes a 
thick three layer (cork-metal-cork) valve cover gasket that can make the 
difference with clearance problems. Permatex the gaskets to the valve covers 
and run them dry on the head side if you plan on frequent removals. It is 
possible to run adjustable valvetrain, roller rockers and a stud girdle under 
a Boss aluminum valve cover. 

- Drive a second shear pin in the distributor gear or replace with a hardened
pin. If a little debris (see valve seals below) gets in the pump gears, it 
can shear or bend the pin. This retards the timing which leads to sluggish 
performance and overheating. 

- Don't use umbrella valve seals. Use PC-type teflon seals. The umbrella 
ones disinegrate over time and fall into the pan where the get sucked up
by the oil pump.

- The usual Ford oil filter has a bypass valve bult into the filter which 
can allow unfiltered oil to bypass the filter. The bypass can also fail, 
causing a loss of oil pressure. Consider using Purolator oil filter 
number L30119. It's a full size replacement for the FL-1A Ford/PH8A Fram 
filter. It has no bypass spring in the middle but it does have the rubber 
flapper for anti-drainback. The original application is for a 1978 Nissan 
510, 2.0L 4 cyl engine (L20B) which had the bypass valve in the engine 
block. This filter cross-references to a Fram PH2850, a Motorcraft FL-181,
and a Wix 51452. However, those filters have not been verified and may 
still have the bypass. It appears after 1978, Nissan went to a half height 
filter. Purolator part number L22167 fits that application and does not 
have the bypass spring but does have the rubber flapper for anti-drainback.

- The stock rods are good to 7000+ rpm with prep. At a minimum, use good (ARP) 
rod bolts. Beam polishing and shot-peening are also good but optional.
- Run a PCV valve

- Use a Cleveland specific thermostat. They have a shoulder which is sized 
to match the brass restrictor ring in the block (make sure it's there) which 
other thermostats do not have. Using a Windsor thermostat (which the parts 
counter monkeys will give you half the time) will lead to overheating because 
coolant will bypass the radiator. Don't run an excessively cool thermostat. 
It won't make a difference in steady state temperature but will slow warm-up 
time. I recommend the Robert Shaw 351C thermostat. It's quick acting and 
has bleed provisions.

- 4 bolt mains are a nice-to-have but not necessary.

- If the car is set up to handle, use a baffled, oversize, oil pan. A stock
Pantera with slicks can pull over 1.0 g's lateral and the oil in a stock
pan will climb the side of the pan starving the bearings for oil. I know
two Pantera engines that were ruined that way. 

- The MPG "Stinger" exhaust port plates may be worthwhile for 4V heads if the 
header doesn't turn down sharply at the port exit. The intakes port plates 
may be more of a sealing and port match hassle than they are worth. Roush 
and Marino Perna at Panteras East make intake port stuffers that go inside 
the intake port. A thin layer of epoxy is used to bond the stuffer to the 
pot and set screws are used to hold it in place.

- Quench heads (2V Aussie or early 4V) are the best for performance. They 
allow higher compression and make more power. Quench heads have a flat 
area opposite the spark plug and an open area around the plug. As the 
flat top piston rushes up toward the head, the area under the flat reduces 
quicker than the area under the open part of the head. The result is the 
mixture is forced at towards the plug. The resulting turbulence evens out 
temperature and more completely burns the mixture. More power, better fuel 
economy, and higher compression on the same octane. 

- For street applications, flat top pistons (TRW forged or KB hypereutectic)
are generally used with the quench chambers for a compression ratio in the 
10.5:1 range. Pay attention to the manufacturer's ring gap information you 
plan to use nitrous.

- Quench heads run best with less spark advance (32-34 degrees) than open 
chamber heads. The flame front has a longer distance to travel with open 
chamber heads so they require more total advance, maybe 4 degrees or more 
than a closed chamber head. A multi-strike ignition, like an MSD-6 series, 
will allow an open chamber head to make peak power with less total advance. 

- With an open plenum intake and some cam, I like the multi-strike ignitions 
like the MSD-6AL (the -AL version comes with built-in rev limiter). They 
improve cold start and low rpm performance. You can use any distributor to 
trigger. 

- Use a quality double row true roller timing chain set (Cloyes, SVO, or similar). 
Degree in the cam and mark true TDC on the balancer. Stay away from gimmick 
dampers (TCI Rattler, Fluidamper, etc.). Stick with a stock or quality rubber 
elastomer type balancer (SVO/ATI, ROMAC). Paint a stripe on for a positive 
indication of balancer slip.

- If you need new cam bearings, cut grooves on an old Cleveland cam to use as a 
scraper or have a machine shop hone to fit. Cleveland cam bearings were honed 
in the block by the factory and new ones are usually too tight.

- For high rpm work with a solid lifter cam, consider the standard oiling mods 
(galley restrictors and/or sleeved lifter bushings). For under 6500 rpm 
with a hydraulic cam, stock displacement oil pump with a higher pressure 
relief spring (or shimmed) is okay. High volume pumps increase output at 
lower rpm where it's not needed, unnecessarily loading the cam and distributor 
gears and wasting power. Use the SVO or FPP heavy duty oil pump driveshaft.
MPG Head Service (a.k.a. Cam Research) makes a windage tray to fit the stock 
pan. The 351M/400 can type pickup can be used to replace the 351C pickup. 
Make sure the pickup and the hole in the mating surface align.

- Check the cam and distributor gears for proper contact pattern. You may have 
to adjust the position of the gear on the distributor. Also, it's worthwhile 
to pull the distributor after a few hundred miles to check the wear pattern. 
There have been a rash of cam gear problems that may be due to improperly 
machined cam cores.

- Treat 2V and 4V engines as completely different when it comes to picking 
components like cams, heads, and intakes. The primary difference between 
2V and 4V heads lie in the ports. 

- 4V heads have very large ports. The intake, though overly large for most 
applications, is shaped decently enough. The exhaust is compromised to 
clear the shock towers of early Mustangs and Cougars. The 4V exhaust 
port has a hump then a sharp drop with an exaggerated area change. The 
port exit area is very large but much of it is wasted and the flow 
velocity low. The resulting poor intake to exhaust flow ratio requires 
a cam with additional duration (typically 10 degrees or more) and lift on 
the exhaust side for best results. 4V heads work best with a dual pattern 
cam. Something on the order of 10 to 20 degrees additional exhaust duration 
and/or 0.010" to 0.020" additional exhaust lift. 4V heads also like a lot 
of lift and keep flowing more air past 0.600" valve lift. The 4V exhaust 
port is sized for a 1 7/8" primary diameter header.

- The best horsepower intake for the 4V heads is the Holley Strip Dominator. 
It's a single plane and gives up some low end torque but it's still 
smooth and tractable. The Strip Dominator is currently out of production 
but can be found at swap meets and on the 'net for $325 to $350. A close 
second is the Blue Thunder high rise dual plane. It gives up a bit of top 
end but has a better low end and cold weather start up. These go for 
around $325 new and are available from the usual Pantera vendors. Both of 
those intakes are quite tall. If hood clearance is an issue, then you're 
best choices are a stock Ford intake or an Edelbrock Performer 4V (a.k.a. 
F-351 4V). The Ford 4V intake were produced in iron or aluminum in square 
or spreadbore (Motorcraft, not Qjet or Thermoquad) versions. The Offy Dual 
Port is probably the best fuel economy, towing, intake for the 4V heads.

- The 2V is a whole different cylinder head, not just a 4V with smaller 
ports. The oval ports are smaller, though still decently sized. The 
intake ports are biased to the side to get a straighter shot at the valve. 
The exhaust port is raised (relative to a 4V), has a moderate area change, 
and a nice shortside radius. Though much smaller in cross-sectional exit 
area (though not necessarily a smaller minimum area), the 2V exhaust port 
flows as much as a 4V, with substantially higher velocities. The 2V exhaust 
port is sized for a 1 3/4" primary diameter header which is more than 
adequate for 400+ hp. You can use 1 7/8" diameter 4V headers on a 2V port 
but you'll loose some of the scavenging effectiveness. Since the heads have 
a good intake to exhaust flow ratio, they don't require an exaggerated dual 
pattern cam like the 4V and work well with a single (or slightly dual) 
pattern cam. Unported 2V heads tend to build flow early (have good low lift
flow) and level off after 0.530" lift or so. 

- No high rise dual plane intakes exst for the 2V heads. However, the single 
plane Weiand Xcelerator 2V (p/n 7516) is a good high performance intake that 
works smoothly at low rpm. The Weiand's intake has ports that are larger 
than those of the head. It's essentially pre-ported and requires the heads 
be match ported to the intake. For a heavier vehicle, you might want to 
try the Edelbrock Performer 2V (a.k.a F-351 2V). It's a low rise dual 
plane with that ports match the size of the head ports. Holley made a Street 
Dominator (p/n 300-12) open plenum single plane intake for the 2V heads but 
it was an economy type manifold it ports smaller than the 2V head and a small 
plenum. An Offenhauser Dual Port would probably be better for fuel economy 
and low end.

Dan Jones