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I picked up a set of cnc ported 799 heads. Unfortunately there is no obvious marking to suggest who did the porting work. These have passed through several people and were claimed to be TSP Stage 1 but they are not marked as TSP says they would be. Valves appear to be stock gm, stock sizes.
Only non-factory markings I can find are: Letters MKN on one end of each head and PG515 on the casting number pad.
Maybe it's the pictures but it doesn't even look ported. Looks like someone just carved their initials in the head with a razor blade.
If you zoom in on the intake port picture you can see the perfectly parallel cuts from the cnc machine. All the ports are like this. I also compared them to a stock 243 head on hand - no doubt they are ported.
I got a response back from WCCH, not their work and no suggestions on whose work it may be.
I sent an email to AI, awaiting a response from them.
I did disassemble and start cleaning them up hoping to find some other markings. No luck with that but it appears there has been significant work to the combustion chambers. Is that normal for a stage 1 porting? ported 799 Stock 243
I got a response back from WCCH, not their work and no suggestions on whose work it may be.
I sent an email to AI, awaiting a response from them.
I did disassemble and start cleaning them up hoping to find some other markings. No luck with that but it appears there has been significant work to the combustion chambers. Is that normal for a stage 1 porting? ported 799 Stock 243
Would have been nice if they were WCCH, not too sure. I normally get 799/243 done by FED but they normally do not touch the chambers tho.
While not radical, I wouldn't call it Stage I. Usually chambers aren't done with Stage I, but who knows?
I was calling it a stage 1 porting because the valves are still stock and the guy I bought them from called them stage 1. It seems to me that larger valves are usually a notable difference between a stage1 and stage 2 porting.
I guess I'm going to have to measure the cc's now. I need to know what the compression ratio will be. Might as well do the runners too I guess.
I was calling it a stage 1 porting because the valves are still stock and the guy I bought them from called them stage 1. It seems to me that larger valves are usually a notable difference between a stage1 and stage 2 porting.
I guess I'm going to have to measure the cc's now. I need to know what the compression ratio will be. Might as well do the runners too I guess.
Yeah I wasn't arguing, just saying what my experience was. If what you have is a Stage I, it's a GOOD Stage I!
I have yet to contact Lloyd Elliot, I have measured the ports and combustion chambers though. Intake ports are 225cc, exhaust ports are 86cc and combustion chambers are 61.5cc. Since I can see that material has been removed from the combustion chambers these heads must have been milled to shrink the chambers.
Is the milling a negative? I have to crunch the numbers and see how the size of the combustion chambers changes my compression ratio but if that's ok is there any other disadvantages to the milling? PtV clearance perhaps?
Since 799/243 heads are normally 210 intake, 75 exhaust, and 65 chamber, these should be some nice heads!
If the chambers weren't opened much, they wouldn't be milled too much either.
Milling in itself isn't a minus. PTV would really only be a concern with a high duration, high overlap (low LSA) cam.
Did some number crunching on the CR. I'm building a sbe LS2. I was planning on running .041 thick head gaskets for better quench. Using .007 above deck I get 11.82 static and 9.04 dynamic with the BTR Stage 2 cam I was planning. Stock thickness gaskets net 11.49 & 8.79
Did some number crunching on the CR. I'm building a sbe LS2. I was planning on running .041 thick head gaskets for better quench. Using .007 above deck I get 11.82 static and 9.04 dynamic with the BTR Stage 2 cam I was planning. Stock thickness gaskets net 11.49 & 8.79
Is this too high a CR for pump gas?
You’d have to run 93...assuming...that 93 in Canada is the same as 93 in America. I’m at 12.42 static & 10.48 dynamic and run fine on 93 with a very efficient cylinder head/chamber design. 27 degrees of timing at full song as well, but tried 30 and no knock.
11-10-2019, 09:16 AM
Help to I.D. head porting 
