1969 273 upgrade advice

1. Find a set of 920 heads. Run stainless valves. You'll have to cut a set of 1.88s down to 1.84. The exhaust should be find. No need for hardened seats. The 272 2bl advertised at 8.8 to 1 CR. If the block hasn't been decked youmay be able to bump the CR up a bit by shaving a bit on the heads and running a thinner head gasket. You'll have to do the math.

2. The 340 grind works real well. Another grind is the Isky E3. As far as I know it's not being offered anymore however the specs of the cam are. The E3 was a solid cam so if you don't want the maintenance issue of adjusting valves go with a good hydraulic cam.

3. In my opinion the Edelbrock LD4B by far is the best intake for the 273. It's based on the Edelbrock LD340 only with smaller runners and ports. The LD4B was. Stock replacement intake offered by Edelbrock. It was also offered as an over the counter speed part with a MOPAR part number. As far as a Carb, either Holley 1850 or a Carter AVS. Real good carb which works well is the Carter Competition Series 9636. Not made anymore but plenty of them out there. Rated at 625cfm it works real well with a 273. Carters are real easy to tune.

4. Small displacement like the 273 requires some gear. A good compromise are either 3.23s or 3.55s. I wouldn't go more than 3.55s unless you are spending a lot of time at the track.


5. Of course a rear end change is probably in order. I had a 67 Dart GT with a 273 that had these Mods and with 3.23s I could get 18MPG with freeway driving.