The 200 to 250 head swap clarifications

[Anonymous]

Okay. now that I have the science behind the head swap, I need to know what to tell the machinist. I know that it depends on what I want to do. But What do I need to upgrade for it to be worth my time (ie new valves lifters springs, etc). I would like to direct mount a 2bbl, that i should be okay on. I know i need to mill the head. I hear I should get a 3 angle valve job. I am looking for some insight on this. Pardon my lack of info, I'm young. What is a 3 (or 4 for that matter) angle valve job?
Do I need new valves? If so what will work for a non- drag racing application? What head hardware will I need to purchase and should all of it be available at the parts store? Thank you very much.

Steve

 

[pedal2themetal45]

HI
this is what I got from czln6 this should help ya..
Tim

<<Howdy Back Tim;

After '69 the 200 and 250 heads are the same.

The after '75 heads will all have hardened seats, and a 1.75" carb hole for the larger T-bore carbs. After '77 Both 200 and 250 heads will have 1.75" intake valves and 1.5" exhaust earlier 200/250 will have 1.69" intakes.

All of these heads will have 62 cc chambers and will need to be milled to attain your compression goal. Remember to mill to compensate for the thicker Composite head gasket too.

Whatever head you do you would be wise to do a valve job, especially for economy. Be sure to specify a three angle valve job, back cut the intake valves and mill to achieve CR. Cleaning up and smoothing the chambers will help with minimizing hot spot pre-ignition for a leaner air/fuel mixture.

Be sure to check deck height and piston dish and add that into the formula for figuring CR.

For economy, you should at least go with a 9:1 CR. Higher if your elevations is above 3,500 ft.

Adios, David >>>

 

[Anonymous]

Thanks a bunch Tim (and david indirectly).
I appreciate your help. What exactly is a 3 angle valve job though? Can I keep all the old rockers and springs and such? I have to step my way through this resto mod and i am wondering what kind of money I will be spending.

Thanks again,
Steve

 

[pedal2themetal45]

HI
I don't know about the rockers and springs I beleve you can click on the sticky that David started (the last one) and then click on PM him in the post. Then ask him I'm sure he'll be glad to help
tim

 

[Anonymous]

Thank you sir.

Steve