cam patterns

[250coupe]

witch kind of cam is better fo a 250 inline six dual or single pattern

 

[CZLN6]

Howdy Back:

IT really depends on the total package and intended uses.

In general, all most always, (how's that for hedging?) a dual pattern cam, with more exhaust duration will help our engines because of the smaller exhaust valve and the tipped over exhaust port design. It will likely be most noticeable in upper RPM ranges.

Adios, David

 

[rbohm]

8) if you are using the stock log head, even in modified form, a dual pattern cam will be best for overall performance and economy. it will actually work best right in the range where you need it most as a daily driver. if you are going to use the 250 2v head, either of the argentine heads, the crossflow head, of mikes new aluminum head, then go with the single pattern cam, especially if you are modifying the above listed heads, for best overall performance. single pattern cams are best when the intake and exhaust flow is properly balanced, like you would find in the new aluminum head. a dual pattern cam is best when the flows are way out of balance like you find in the log head.

 

[250coupe]

i plan to have bigger exhaust and intake valves put in my 72 loghead would i realy need to put bigger exhaust valves in it, the lift for the exhaust is higher than the intake with the dual pattern cam isnt it?

 

[CZLN6]

Howdy Back:

Upgrading to 1.75" intake valves and 1.5" exhaust valves is a good idea on a 250 regardless of cam pattern.

The critical question remains- what is your intended use for this engine?

Adios, David

 

[rbohm]

8) i agree with david regarding valve size. in fact upgrading to a 1.75in/1.50ex on a 200 is also a good idea. regardless though, using a dual pattern cam with a log head is the best way to go even with the larger valves.

 

[250coupe]

Howdy Back:

Upgrading to 1.75" intake valves and 1.5" exhaust valves is a good idea on a 250 regardless of cam pattern.

The critical question remains- what is your intended use for this engine?

Adios, David

dailey driver with some mild performance, not looking for 200hp