Sounds plausible to me. The last cylinder in the head (#7/#8) will typically run hotter than the rest. That's why, if you are running a single EGT, you put it on #7 to show the worst cylinder. Improved coolant flow to the back of the head will reduce that difference. There is definitely "flow" through the LT1 steam line. I run a coolant temp sensor in that line.

The nitrous guys get heavilly concerned with the issue, since a hot spot can be fatal. Same reason they frequently add a coolant return port between the two center exhaust ports on the SBC heads on very high HP applications... to get extra coolant flow in that area to reduce the concentration of heat due to the two exhaust runners being right next to each other.

 

Along with my single plane conversion, I will be replacing my steam line with -6 AN fittings and lines.



Nick

 

The threads are 1/4" NPT, but they are straight thread. Most NPT threads are tapered. You will either need to run an O-ring type fitting or re-thread your heads to tapered NPT. It shouldn't be a problem to run a tapered tap into the holes, the threads per inch is the same.