Stock Head Question

[Simon@London]

882 and 624 are the weak, crack prone "lightweight" castings IIRC. Almost any other casting is better than those two.

I thought I had the pre 71 882 heads on this 70 build. But my build shop guy got into it yesterday and found the 920 castings in it. ( 1971-75 ) Found a great page here >

http://www.chevytalk.org/fusionbb/showtopic.php?tid/180000/

on doing head work on these old smog heads. Tom Parson's piece is very detailed for any guys thinking of doing this . I used PDQ67's head casting page and only found one listing for 920 heads. Our plan is to port them, adding 1.60 exhaust valves, roller tips rockers, 6 qt oil pan and Z28 Oil pump.
( plus energizer Crane Cam )

That will make enough power for what I want. With no frame connectors these T-Tops have big body twist and I have already noticed it when turning sharp at corners in a hurry. ( feels weird )

Any members on here that have previously used 920 heads at one time could you give some feedback.

 

[pdq67]

Everybody knows how to tell crank-prone heads, right?

They are the "scalloped" ones on the sparkplug side down by the head-bolts.

And I figure darn good heavy heads are the ones off the early 400 engines that have 1.94"/1.60" valves installed in them.

I would just pin the studs and do a Louis/Slotting Tool p/r slot length increase, a good bowl-blend and dingle-berry port casting flash clean-up too.

And as you are at it, cc them.

I ran 350 engine .020" thick MrG. steel shims on my 406 b/c I mocked it up, reached up inside and scribed lines where they overhung, then very carefully removed the overhang and also drilled steam holes in them fine. I did re-torque them three times over as many day's DD driving her.

I forget if I used CopperCote or aluminum Spray paint??

pdq67

 

[Simon@London]

Everybody knows how to tell crank-prone heads, right?

They are the "scalloped" ones on the sparkplug side down by the head-bolts.

And I figure darn good heavy heads are the ones off the early 400 engines that have 1.94"/1.60" valves installed in them.

I would just pin the studs and do a Louis/Slotting Tool p/r slot length increase, a good bowl-blend and dingle-berry port casting flash clean-up too.

And as you are at it, cc them.

I ran 350 engine .020" thick MrG. steel shims on my 406 b/c I mocked it up, reached up inside and scribed lines where they overhung, then very carefully removed the overhang and also drilled steam holes in them fine. I did re-torque them three times over as many day's DD driving her.

I forget if I used CopperCote or aluminum Spray paint??

pdq67

Apparently these are not those lighter heads with only one scallop a third the way along. But did have the wrong intake gaskets and some minor leaking in a few spots. He is doing what you suggested here already and tonight I am going to have a peek at it.