Engine/Transmission (1994 - 1998) All 12 valve heads the same??????

[ctdf]

Are all 12 valve heads the same, meaning all 89 to 98 model pickup, truck or whatever 12 valve head the same, if not what years are the same and what are the differences?



Found a head to replace the cracked head on my 96 cummins, but it is a 91 to 93 I would guess. Any info is helpful.

Thanks, Chris

 

[Lucas5477]

I think the newer 12v heads flow more air then the older ones. I don't know if they are all the same though.



Lucas

 

[Jim Fulmer]

Chris, here is an issue I just ran into, working on a truck with a cracked head and I found one locally... . brand new so I went for a look, it was an old 89 to early 91 head with the big 9mm holes for the injectors vice the 7mm on the newer heads, so what do I do, call the fine folks at PDR and ask about it and that was the info I got from them and I knew that it wasn't the best head, and prone to crack, so I ordered one from them, now what I got was a new head with Piers's specs on the deck to my door for a whopping $50. 00 more than the one locally.



Jim

 

[Missouri Mule]

I recall reading a service manual or thread that you could not use a non intercooler head on a intercooler head and vice versa.

 

[onestackdram]

You can not use the 1st gen heads on the second gen blocks, Yes they will line up and things may seem to be somewhat the same. But you will have issues with air flow, and not to mention, on some (Can't remember what years) but the inj. are on the wrong side.



Russell

 

[JGheen]

Can you port a 1st Gen head to flow equal to a 2nd Gen or even more than a 2nd Gen?? Not sure if you would want to, but just a thought.

ctdf - I would probably just bite the bullet and get a new head or see what Piers has for sale. If mine ever cracks or the head gasket goes I am just gonna buy a new one from Piers that is O-ringed ported and ready to go. Again, just a thought.

 

[Jim Fulmer]

on some (Can't remember what years) but the inj. are on the wrong side.



89/90 and early 91 had the 9mm injectors.



If mine ever cracks or the head gasket goes I am just gonna buy a new one from Piers that is O-ringed ported and ready to go.



If anyone is ordering a head from Piers, that person would have to be crazy not to get the O-ring job done for a mere $300. 00 more, shipping only to do it later would cost more.



Jim

 

[onestackdram]

Well, I would be guessing, as I am not a machinist, but I would make a GUESS that you could probably port one out and polish it, to be slightly better than the 2nd gen head stock. But that wouldn't answer all your issues. It would just be better to buy a KNOWN 2nd gen and be safe. They will cost you about the same give or take a little. And you get the assurance that you have the right parts. Now just for knowledge sake, ANY 2nd gen head will fit (12v to 12v). Technically ALL 5. 9 heads from 89 to 02 can be MADE to fit. But your talking alot of machine work, alot of custom making different pieces, and on top of all that things may never be quite right. It is ALWAYS safer to just stick with the proper head that you know goes to it, and modify from there.



Russell

 

[Vaughn MacKenzie]

Porting

There is a guy on NW Bombers who ported his own head, ATS manifold, etc. He has a '93 with DD3 injectors and a few other things. He has dynoed at 335hp/925 torque, not bad for a little VE-pump motor. There is definite gains to be realized with a quality port job.



Check out--> http://www.nwbombers.com/cgi-bin/forum/ikonboard.cgi?;act=ST;f=3;t=7097

 

[ctdf]

How much would a Piers stage 2 head reduce EGTs and does your trucks seem to run or dino better and how much does a 4 inch down pipe help EGTs Thanks, Chris

 

[onestackdram]

Well the 4" down pipe (coupled with and atleast an entire 4" system) should drop egt's anywhere from 50-100* But that is entirely up to your foot. A port job should do about the same maybe a little more, and with the proper exh. manifold matched to it even better. It's almost pointless (In MY Personal OPINION) to do a port job on the head with out having a manifold matched to it. The whole point is to get air in and OUT quickly, evenly, and with the least amount of resistance possible.



Russell