Sooooooooooo , if I use the stock 1968 318 which I think came with the open chamber 675 heads ,..... can I switch to my 920 closed chamber heads with my erson ?
OK, You can go to 920 heads bump the compression up a bit. It is not compression that makes power. Compression is an adder. Flow is a multiplier. You can play the game of high compression then a big cam to bleed off pressure. I am not up for it. I am a strong street runner, not a racer, and I am cheap. I have a friend who raced Super Stock Class, back when you could not port heads. His friend raced Stock Class. Their cars were very fast. It gave you an idea of what stock parts in engines were capable of, if you had good machining and the right combination of parts. A 273 is a great engine with good compression for todays gas, if you put the right combination together. As you know they are quick revving and very efficient. The heads flow plenty for 273 cu in. Untouched 273/318 heads give you about 170 cfm intake and about 120 cfm exhaust. Untouched 360 heads give you about 190 cfm intake and 140 exhaust cfm, Untouched 340 heads give you between 200-220 cfm intake 145 cfm exhaust. Untouched Magnum heads flow about what 340 heads do with + 20 cfm on the exhaust, if I remember correctly. Magnum EQ heads are even better. The point is, you should decide what you are up for and how much money you are willing to spend. It is the combination, and I mean all of it, that gives you the quick revving monster you had for a while. You are talking about getting a second engine and swapping parts between the 2. I don't think you will be happy going that rout. It is cheaper to get the right cam for the 273 and use the Erson cam in the 318. But I'd go with at least 360 heads on the 318. Then new pistons. Deck the block. Then bore and hone with torque plates. Mill the heads .040 on the block side and .038 in the intake side. Add Stainless steel valves and beehive springs. Balance everything. Sell the 650 and get a 750 carb. Change out the bellhousing and flywheel so you will have a chance to hold the power you are making now, in a 66 Cuda? You see where I'm going. Oh, and I have done all this and more. The 64 was so fast you had to drive around town in 2nd gear or the next thing you knew you would be flying. And that was a 273. But it was truly great watching my mother drive it...