budget 273 build

JJR said
Hello, my name is Jedidiah Rumbolz. I have a 1966 dodge dart gt with a 273 that is in need of a rebuild. I was wondering if any of you know a couple tricks to get a couple easy horses out of this engine. I am aware of a package called the D- Dart that dodge did in 1966 for racing in D/Stock. I believe it had a 273 with a .500 lift cam, 4speed, and a 8 3/4 with 4.88 gears. Will the heads on my engine flow at that lift? I only planned on taking this engine to 6000rpm. How much spring pressure can a stock valve train take?

I wouldn't build it to D Dart spec's.
Building a 273 is like any other engine CR/Cam/Headers/Porting/Intake&Carb

273/318 heads flow a little low for a 318 but are plenty for a 273 size engine though
probably not much in the .500 range. With reasonable cam and CR they flow enough for 300-325 HP. pocket porting and port matching is always helpful plus it help you make good power with a smaller cam which is one of the two things you dont want to over do on a 273 Carb being the other. Something like 9:1CR, comp xe262h, 1 5/8 headers and a dual plane with a 600 cfm carb.

Plus a ???HP 273 is gonna have less bottom end power than an equal hp 360 and gonna make it at an higher rpm so your gonna need to run a lot more gear for similar performance. minimum i'd go is 3:91 but 3:55 and up is good. and the so called 10.5:1 pistons are more likely gonna give you low 9 CR.

Also read the sticky on porting 318 heads