I took my last set of D0OE heads to the dump for the reasons below.

There is a lot more to using these heads. First of all, they are most likely "worn out" and will probably need valve guides, new valves, springs, maybe retainers and locks. Add in 16 new seats for unleaded gas plus a set of rocker arms. Then a set of screw-in rocker studs. Then, if they have the infamous EGR bump in the exhaust runner, you (or someone) will need to spend a bunch of hours grinding it out. They will have to be tanked then milled for levelness. If you mill them more then just a few thousandths for clean up, then the intake will have to be milled as well. All this will be more then a set of after market heads - not cheap.

If you can find a set of low mileage GT40P heads, this is the cheap way out. If not, there are many reasonably priced OK to great aftermarket heads that are all better then the D0OE's.

289 (most are 52 to 55cc) heads may bring your compression ratio to well beyond what you really need for the street and today's gas, 10 to 1 or more