A guy once told me that when the 6.5 was made the heads were designed to make the engine run quieter but this took away some power. He said to build a good engine you should put 6.2 heads on a 6.5 block. What is the difference in the heads. Would this work?

that guy should have his toolbox locked up and the key thrown away.

6.2L heads have slightly larger exhaust valves, they were downsized as an attempt to solve the common cracking between the valves problem 6.2s had.

Maybe the guy meant that with the larger exhaust valves you would have a little better flow = more power. But I wouldn't suggest it if there is a common cracking problem. You would increase you risk for little noticable performance.


So I wonder if putting 6.5L heads on a N/A 6.2L would be a good idea to decrease that risk?http://www.dieselplace.com/forum/smileys/smiley24.gif

'82 only had the .100" larger exhaust valves.

Totally agree with grape......


The differences are -


6.2 up to '90 had injectors angled more to side of engine


'90 up angles revised for turbo installation, more vertical with shorter injectors


6.2\6.5 normally aspirated heads got specific pre-chambers


turbo heads got re-shaped pre-chambers for revised spray pattern


n\a injectors 'pop' at 1500psi


turbo injectors 'pop' at 1700psi


van and hummer heads got revised intake surface angles - not interchangeable with truck heads\manifolds


can use turbo heads, injectors with turbo inj pump DB2-4911 - Mo' Powah!


no other changes in camshaft, lifters, port sizing - nada


Almost fergot - 195hp 6.5 is a lot noisier than 135hp 6.2, so guess them 'quiet' heads didn't help much in the noise pollution depthttp://www.dieselplace.com/forum/smileys/smiley19.gif


Edited by: gmctd