041 Heads VS. 186s on a 302

[L78 steve]

How often do the 041 heads show up on the 302 .Does anyone have these on their 69s and if so is there a date range that they were used ?

[JohnZ]

How often do the 041 heads show up on the 302 .

They don't, from the factory - '69 302's only used the 186 heads. L-48's used the 041 heads.

[L78 steve]

So the popular publication is incorrect is stating that they were used ?

[JohnZ]

So the popular publication is incorrect is stating that they were used ?

I'll defer to Jerry's knowlege and expertise, but I've never seen a '69 Z/28 with 041 heads.

[L78 steve]

It's the Colvin book that has the 041 as an alternate casting .But if you have never seen them on a 302 that's good enough for me .I have someone that has a set for sale and he is sure they came off a 302 .They are the correct dates for me,Oh well .

[Jrschev]

That's interesting. If the 186 heads are 302 only (if I understand correctly) I have a set in my garage that are dated January 1970. (A 21 0) & (A 22 0) Where would these have been used. I'm not convinced that 186 heads were not used on other small block engines such as L48 and perhpas the LT-1.  Why would these be cast in 1970. Again, my favorite expression with Chevrolets of this vintage: The only thing that was consistent is inconsistencey.

[Hot Rod Todd]

I have a set of 186 heads that came factory on a 1970 Impala 300 horse 350. These are 1.94 valves. I am sure that any factory 186 for a Z/28 would be 2.02 intake valves only. They used the same casting just machined them for the bigger valves when used in a Z/28. Same goes for the 291 castings for the 1968 models.

[Jrschev]

That makes sense. I'm going to check the valve diameter to see exactly what they are. I'm sure that is the explanation for it. I forgot they used that combo (350/300) in the big cars. My dad had a 69 Caprice back in the day with that engine. That car was a big deal because it had air conditioning!

[JohnZ]

186 heads were also used on the 1970 Z/28, but they were machined for screw-in studs and pushrod guide plates; Z/28 applications used 2.02/1.60 valves.

[L78 steve]

The 041 heads I looked at have the 2.02/1.60s and screw in studs with guide plates C 5 9 date .Corvette ?

[69Z28-RS]

I don't believe any '69 Chevrolets were delivered with guide plates and screw in studs, so that additional machine work must have been done later, as the larger valves also would have been done later as well.

[redge]

I have 041 on my L-48 but in the book «chevrolet by the numbers» they said some 041 heads were use on 302

[JohnZ]

The 041 heads I looked at have the 2.02/1.60s and screw in studs with guide plates C 5 9 date .Corvette ?

Nope - the only '69 Corvette that used 041 heads was the base 350/300hp, and it used 1.94/1.5 valves, press-in studs, and no guide plates.

[Jerry@CHP]

Steve,

Have never seen 041's on a Z28.  Have only seen them on the L48 engines.  These heads turn up a lot on the L48 with the 388 engine block casting.

Jerry

[L78 steve]

I guess I will have to keep looking for a nice set of 186s .Every set I come across has been ruined by angle milling .