heads are different

[SickNasty]

was putting my motor together and noticed the heads are different. one has a support on the coolant passage and one does not. believe one may be a turbo head and another n/a?? is this ok to run? are the combustion chambers the same size?

View attachment 193886View attachment 193886

 

[charlief1]

Pics didn't load. What are the casting numbers of the heads?

 

[SickNasty]

ill try to post pics again. casting numbers were the same. there was another number stamped separate from the casting number that was different.

 

[SickNasty]

just sucks bc its already been ported and had valve job. I cant believe I didn't notice this until now.

 

[charlief1]

My guess is that the last 3 digits of the casting number were 293, right? The early 293 casting didn't have the bridged passage and was the basis for the Stage I heads. Shouldn't be an issue but the 1 without the bridge may blow the head gasket a little easier.

 

[SickNasty]

yes I believe it is 293. the one with the bridged passage has a lot more meat on it in certain areas so head gaskets would be my concern as well.

 

[charlief1]

All the heads from 79 up are basically the same. All of them are high port with minor differences. All will seal on all the blocks from 77.5 up.

 

[SickNasty]

awesome. well ill give it a try. thanks for the help and good news

 

[750H.P.V6]

It should work fine as long as the combustion chamber volume is the same on both heads.

Neal

 

[Ttype6]

The intake and exhaust ports and combustion chamber shape and volume are the same. The older head is thinner decked and more flexible and will blow a gasket before the newer/bridged one will. If this is true,the newer/bridged one should weigh more than the older one.

 

[750H.P.V6]

What I was implying about the combustion chamber volume is that if one head had been surfaced more than the other it's possible that there would be a difference in volume. I ran 6293's on my old stock block, I'm fairly sure the deck surface is the same thickness. The bridged water passage on the end of the 8445 casting doesn't really add much in regard to head gasket sealing.

Neal