small block heads

[jacksdodges]

Ok here is my question. What is the difference between these two 360 heads. 4027596 and 4448308? All the difference like CC and which one is best? Will they work together???

 

[rmchrgr]

596 and 308 are fairly similar on the intake (both have 1.88 valves) but the 308 has a more efficient exhaust. 308 was the late '80s head that came on roller blocks so they have enlarged pushrod holes. There's also the little smog ports that you have to plug for performance applications.

The 308 used to be the most sought-after factory part by NHRA class racers who had to run factory iron heads. Pretty sure those guys can run aluminum heads now but back before the rules changed, the 308 was the hot ticket.

You could probably make them work from side to side but you might get some uneven stuff going on. Despite the fact that the 308 came on roller blocks, the valve gear is essentially the same on both heads, as are all the accessory bolt holes etc.

 

[txstang84]

308 intake ports have a smaller pushrod pinch because of the increased pushrod angle required by the taller roller lifters, they've been worked by members on this site to flow similar on the front side as X or J heads-or better. As mentioned above, the exhaust side is much more efficient than X or J castings.

IMO they shouldn't reside on the same engine mixed unless there's been extensive work to ensure the chambers and ports all match flow and size...

You'd do well to find another 308 head, or a refurbed pair.