250 Camshafts, Gears Sets, and Retarded Timing

[blakphi]

All,

I have a question about camshafts and timing chain sets. Are all the 250 factory camshafts the same specs? If not where can I find the specs?

I also wanted to know if the timing gears on the 250 are similar the ones on the 302, in the way the gears were changed to retard the timing in 1973? In 1973 Ford changed the timing gears to retard the timing for either emissions and/or economy. On a 302 the camshaft is more or less the same from 70 up, so if you want a 73+ engine to perform better you can use the 70 gear set on the 73+.

Thanks in advance,

 

[CZLN6]

Howdy Blake:

The best we could find from various sources is that the ealyy 250 cams show 256 degrees of duration, lift @ .368". They appear to be advanced 4 degrees.

Later are also 256 degrees duration, but show .372" lift and appear to be retarded a bunch.

It is clear that the cam timing gear after '72 accounts for a bunch of the retard.

If you're changing timing sets and want the early timing take a look at NAPA numbers S414- cam gear, B415- crank gear, and 9-363 for the chain.

200 stuff and 250 stuff do not interchange. AZmike has a double row chain set for 200 but not for the 250- Yet!!!

That's what we know- for now.

Adio, David

 

[addo]

There is a JP set we can't get info about:

JP 5608 to suit Canadian Block 250cui six cylinder.

It may be in fact that it's a gear set for the 240/300.

From memory, the biggest hurdle to Az supplying aftermarket chain/gearsets was the requirement for a fully new crank pulley which had batching requirements (and thus appreciable initial cost).

Regards, Adam.

 

[blakphi]

Thanks for the responses, we will see how this works out, I am installing the 70 timing set and a 78 head, heading to the machine shop right now. My goal is to reduce the 0-60 time in the Mustang from 15 seconds to about 10. To get there I am replacing the 200 with a 250, replacing the c4 with an aod and changing the rear gears to 3.55s.