221 final decisions...

XMFalcon221

Well-known member
Gday guys, sorry for another run of the mill "cam selection" forum question but I would really appreciate some advice on this one.

I am just about to start putting together a 221 for my XM Falcon now that my aluminium head has arrived. It will have a 5 speed manual trans and will only be an occasional driver.

Of course driveability is a factor but to be honest I am really after a beastly sound from the old girl to turn heads and get the V8 crowd thinking... The Falcon's paint is "farm fresh" which I love, people spend big dollars trying to get the same ratty look so I want an exhaust note to match its attitude.

I was all set to run a 274, 228 @ .050", 110° LSA solid cam from Schneider but it arrived damaged and when I degreed it it has actually been ground on a 107° LSA.

I also have a Clay Smith 278, 230 @ .050" (measured), 108° LSA solid cam but its measured lift of .475" is lower than advertised (.505" with 1.65 rockers)

Basically I cant decide between the Clay Smith 278 that I have or perhaps ordering the Clay Smith 292, 240 @.050", 110° LSA from Mike?

Other specs are:
221 from an XT Falcon +.040"
Aluminium Classic Inlines head, dual springs
Flat top Hypatec pistons, zero deck
Yella Terra 1.65 roller rockers
DUI recurved by Bill Ambler
Compression to suit final cam choice (will be approx. 8.5:1 dynamic)
Classic Inlines 4 barrel manifold, Edelbrock 500cfm carb, 98 octane fuel
Headers with dual 2.25 exhaust
Celica 5 speed, 3.5:1 diff, 1200kg approx. vehicle weight

I can put up with it being a pig in traffic as most of my driving is on open coastal roads but I don't want it to be a total mess...

Any advice appreciated :D
 
The 278 cam should be fine? It will be cranky but that's what your after. Whats the lift measured at the lobe?
As rocker geometry can affect the lift at the valve along with valve lash.
Hope this helps.
 
Thanks mate, yea I think the 278 will probably do nicely for what I'm after.

Average lobe lift as measured is .292", all lobes are within a couple of thou of each other. The dual springs are probably overkill for this much lift but at least float shouldn't be a problem..
 
Have you done any work to cylinder head? I crunched some numbers should turn to 6500 rpm
no problem providing bottom end is up to it.
 
Haven't touched the head as yet, it only arrived from the states a couple of days ago ($400 customs fee later..) I will probably just clean up the castings in the ports as there are a few rough spots.

There is also a hole about 2mm in diameter that goes from one of the pushrod holes through to a spark plug hole, looks like a casting hollow that has been exposed, fingers crossed there aren't any others that could cause bigger problems. I'll get this hole welded up when I send it off to have it decked for the final chamber size

Hopefully bottom end will be good to go, I'm using ARP rod bolts, main studs and head studs. I'll balance the rotating components by weight matching but I'm not sure if there is a machine shop down here in Tassie that can balance the crank
 
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