Anyone know what these cylinder heads are?

[Eric J.]

I picked up a set of cylinder heads thinking they were 186 LT1 heads, but they are not. Does anyone know what they are?

There is no part number cast in the head. Only 3.23 and 180 cast

head1sm.jpg
head2.jpg
head3.jpg
head4.jpg

Thanks Eric

[Joe L.]

Re: Anyone know what these cylinder heads are?

I picked up a set of cylinder heads thinking they were 186 LT1 heads, but they are not. Does anyone know what they are?

There is no part number cast in the head. Only 3.23 and 180 cast

[ATTACH=CONFIG]58836[/ATTACH]
[ATTACH=CONFIG]58837[/ATTACH]
[ATTACH=CONFIG]58838[/ATTACH]
[ATTACH=CONFIG]58839[/ATTACH]

Thanks Eric

Eric------


I have never seen a set of GM heads that didn't have a casting number on them somewhere. In any event, these are DEFINITELY NOT GM '186' heads. Based on the end configuration, I'd say they are much later heads

Obviously, Competition Cams guideplates, if not other parts, have been installed on these heads. These guideplates are not even configured like the GM guideplates.

[Eric J.]

Re: Anyone know what these cylinder heads are?

Joe, thank you. I know now they are not 186s I just find it odd there are no part numbers anywhere. I assume they are some aftermarket manufacture. The mystery continues....

[Joe L.]

Re: Anyone know what these cylinder heads are?

Joe, thank you. I know now they are not 186s I just find it odd there are no part numbers anywhere. I assume they are some aftermarket manufacture. The mystery continues....

Eric-----


They could be aftermarket. However, the end configuration is more-or-less like later GM heads and the date code configuration is very "GM-ish". But, I've never seen any GM heads without a casting number. Even aftermarket heads usually have some sort of manufacturer's ID.

[Terry D.]

Re: Anyone know what these cylinder heads are?

It looks like the 3;23 is a plate, did you try to take it off to if anything is under it?

[Mike F.]

Head450.jpg

[Eric J.]

Re: Anyone know what these cylinder heads are?

It looks like the 3;23 is a plate, did you try to take it off to if anything is under it?

Terry that's cast in the head. Both heads used the same casting as the screw heads are clocked the same.

[Eric J.]

Re: Anyone know what these cylinder heads are?

Possibly C/n 376450; 350 1987-’94 76 cc 1.94" x 1.5" valves?

[ATTACH=CONFIG]58872[/ATTACH]

Mike the rocker stud "bosses" are different on my heads.

[Eric J.]

Re: Anyone know what these cylinder heads are?

There are a couple of differences.

heads5.jpg

[Eric J.]

Re: Anyone know what these cylinder heads are?

Here are a couple more pictures.

head6.jpg
head7.jpg

They have the accessory tapped holes so they are after GM introduced the "Long Nose" water pump 1970? and there are temp sender holes in both.

[Jack H.]

Re: Anyone know what these cylinder heads are?

They remind me of very plentiful (and not necessarily desirable) late 70's/80's era "882" heads. They were produced for many years and had some differences thru the production run IIRC. Full cast number I think is 333882. I've never seen those without casting numbers. Interesting.

[Mike F.]

Re: Anyone know what these cylinder heads are?

I know grasping at straws, but how about Mercruiser/Marine heads? http://bpi.ebasicpower.com/c/MER6N/C...for+Mercruiser

Similar casting marks at least.

FMH.jpg
engine.jpg

[Philip A.]

Re: Anyone know what these cylinder heads are?

They certainly do not look like typical GM manufactured heads based on the underside of the runners, markings and lack of markings (GM). It is possible they are aftermarket. If they were for sale I think they would be advertised as rare GM experimental corvette heads with no identification markings

[Eric J.]

Re: Anyone know what these cylinder heads are?

They certainly do not look like typical GM manufactured heads based on the underside of the runners, markings and lack of markings (GM). It is possible they are aftermarket. If they were for sale I think they would be advertised as rare GM experimental corvette heads with no identification markings

I bet I could hook someone on eBay with that in the description lol.

[Eric J.]

Re: Anyone know what these cylinder heads are?

I put a set of calipers on the valve openings this evening 2.02/1.60