GM Head Questions
 

I'm hoping someone on here can help me answer some questions. I have a set of aluminum cylinder heads I bought many years ago, finally went to use them and the pistons don't have enough clearance with the chambers. I initially thought that they must be closed chamber instead of open chamber, but the info I've found so far indicates that they are open chamber.

The castings are #3946074, date codes 11 14 73 & 7-10-74. I'm wondering if they have been surfaced significantly. Are there any standard measuring points to check for how much heads have been surfaced?

Would it work to use thick copper head gaskets to get the clearance I need?

I also noticed that they have more of a "D" shaped exhaust port. Is this typical for this vintage of castings? The photos of the "D" shaped ports I could find online also showed a ridge in the port floor, but mine do not have that.

These have the holes for 2 extra head studs, apparently for aluminum blocks, but have been plugged with pipe plugs.

Photos below:
http://i238.photobucket.com/albums/f...h/IMGP6150.jpg

http://i238.photobucket.com/albums/f...h/IMGP6153.jpg

http://i238.photobucket.com/albums/f...h/IMGP6154.jpg

http://i238.photobucket.com/albums/f...h/IMGP6162.jpg

http://i238.photobucket.com/albums/f...h/IMGP6164.jpg

http://i238.photobucket.com/albums/f...h/IMGP6158.jpg

Regards,

Re: GM Head Questions
 

they appear from pics to be angle milled quite a bit by looking at the accessory bolt holes. intake valve is a bit out of chamber looking too.

Re: GM Head Questions
 

Thanks, I was wondering of those two end bolt holes are normally the same distance from the deck surface.

The intake valves do protrude about 0.030" past the deck surface.

Re: GM Head Questions
 

that head is for a 69-71 Chevy 396/454 ---- 219 In /188 Ex ---118 CC chamber--- L-88/ZL-1/LS-6 with Rectangular intake port

Re: GM Head Questions
 

Assuming the two accessory bolt holes were originally the same distance from the deck, it looks like they have had an angle cut equal to 0.86° (the holes are 6.72" apart, and the exhaust side one is 0.101" closer to the deck surface). Is this a typical angle cut?

Thanks,

Re: GM Head Questions
 

Re: GM Head Questions
 

Dont waste your time on old tech.........use the new heads like Ed said