ORVette

I don't really know what to look for, but they seem OK to me. They have 1.94/1.50 valves, and I can't visually see any problems with them. The guy seemed pretty cool and said He'd stand behind them. Guess I'll take them out to the machine shop tommorrow and have them checked out. Thanks for the replies to my other post.
Troy

woodworkr

Those are the camel hump heads, same heads that were on the 350/350, 327/350, and the 350/370 LT-1. If they are going to the machine shop may as well have the valves machined to the 202/264 specs, and add the push rod guide plates as well.
Just my .02
JoeB

john's '81 mouse

Troy, heads look good, but can't tell much about condition from pictures.

Have machine shop remove what appears to be a broken off bolt in the accessory hole on the head on the left side of the picture you supplied. They should run a tap in every bolt hole to clean them out before and after heads are disassembled cleaned and hot tanked.

Depending on your intended usage and transmission and rear end combination, you may not gain much by going to expense of changing out from 1.94/1.5 valve size to the 2.02/1.6. If you're running an automatic with 3.08 gears, and you want low end torque, suggest you might be better off keeping the smaller valves, and just having a good three angle valve job done, with a small amount of pocket porting/clean-up done by machine shop.

Have shop check heads for cracks, and flat surface, and mill if necessary, also check valve guides for wear, and have them replaced if worn passed specs, not knulled(sp?). As I said before, if you plan to burn unleaded fuel, you'll probably want to install hardened exhaust seats, as I don't believe these heads came with them.

Also would have screw in rocker arm studs installed, but not necessary to install push rod guide plates, in my opinion, unless you plan to twist the motor pretty tight and do some serious racing. Also suggest you have 'positive' valve stem seals installed, rather than the OEM rubber umbrella seals.

Good luck, and let us know what all you had done to these heads, and what your total investment/cost ends up to be.

Easy Mike

They were also used on the base engine 327/300 for '68. My car has a pair.
:)

Easy Mike

Date codes look good too. E 26 0 and F 8 0 indicate May 26 and June 8, 1970. This pair probably came off the same engine. At first glance, there appears to be too much of a gap between May 26 and June 8, but the Memorial Day holiday pops up between the two dates and the Flint facility would have been closed for the holiday.
:)

Rowdy Rat

Troy,

Good purchase! Looks like head dates of May 26, 1970 and June 8, 1970... Good dates for a late 1970 application.

John's advice is excellent and something that any good machine shop will be doing whether you ask or not (regardless, make sure you mention it). Also make sure that the machine shop pressure tests the heads as it is cheap insurance before putting a lot of money into parts and machine work.

Also very good advice. If you go to the larger 2.02/1.60 valves, the combustion chamber absolutely MUST be cut back to unshroud the intake valve or you will receive no benefit from the larger valve. This is less trouble than it sounds... I'm relatively certain that there is a tool that cuts both the larger seat and the chamber (like the factory did) in one operation. I don't recommend head porting of any kind unless the shop has a flow bench and knows how to use it. Cylinder head porting by intuition doesn't cut it...

The 186 heads do not have induction hardened valve seats like the later heads do and hardened seat inserts are an option that you might want to consider (there are pros and cons to doing this). I wouldn't even mess around with checking 30+ year old guides... Replace them (also agreed the knurling operation that John mentioned should be avoided). The pressure test mentioned earlier will identify cracks that go into the water jackets.

I'd also agree with the advice on the rocker studs... Have the head machined for the screw in studs while you have them at the shop. The guide plates are nice if you already have them, but they are not a necessity (and require hardened pushrods as well). Positive seals... Well, I'd say overkill since the OEM seals work pretty well, but if you're going to do it then use the viton seals currently available rather than the teflon versions that are generally pushed as the "high performance" part.

I just sent a set of 186s identical to yours (small valve/press in studs) off to the machine shop to have much of the work discussed above done. I'll post the financial damage as well as the flow numbers (for those interested) when they are finished. If you aren't in a big hurry to get these heads done, you should be able to get a good idea as to what is involved and associated costs.

Regards,

ORVette

Oops! Itchy mouse finger!


[Modified by ORVette, 11:11 AM 11/29/2001]

ORVette

Wow! Thanks for all the advice and info guys! That thing that looks like a broken off bolt is just a bolt that was left in. I pulled it out this morning and started running a tap down the various bolt holes. So far, so good. I'm going to th machine shop today to pick up another set of heads, so I'll have him take a look at these and see about doing a full blown check up before I start scheming on how to drain a few more hundred$ from the Christmas fund.

PS-Good call on the Holiday falling between the cast dates. Never crossed my mind.