Might try an automotive stethoscope to better isolate the clunk.  An actual automotive stethoscope (not just a long screwdriver) will reach the drive line with out having to get so close to the exhaust pipe and spinning shaft.

I have done wet flow testing, sonic testing, and always go back to individual runner testing before finalizing the averages.  IF and I say IF the individual runner is optimized first, then opening up the manifold for all eight runners to flow through the one port, the flow will be nearly identical in flow.  I have tested that on single plane intakes, dual plane intakes, 6V intakes, 8V intakes, and TW, TR, HR 4V, HR 8V, TP intakes, etc., and every time if the one port is properly blended in the plenum, shaped with taper, the individual flow will be the same as all eight open ports.  BTDT too many times to argue any more about it.  I have flow tested Wilson CNC'd $2500.00 intakes that folks were having problems with fuel distribution on, and found as much as 80 cfm difference between end ports and center ports.  I always try to get the end ports on single plane intakes to match the flow of the center ports, and on dual plane intakes I try to get those within 5% of each ports flow.  The RPM mentioned above has a difference of less than 9 cfm between ports in a dual plane manifold that flows 383.27 cfm.  If that is not respectable, than I surrender to anyone who can do better.  Signing off.  Joe-JDC

I don't think anyone is arguing with you.  It's just you're only addressing one piece of the issue.  I clumsily asked a similar question quite a while back and though I got a lot of useful feedback I didn't get to the heart of the matter in the way folks are discussing it right now.  Fuel distribution involves bringing a gas (air) and a liquid (gasoline) to the combustion chamber in equal, homogenous proportions. 

It helps that gasoline is so volatile but it's density is significantly different than air so complete atomization of the fuel and homogenous mixing with air is difficult to achieve in every runner across the rpm range. 

I found Jay's painstaking efforts on the SOHC dang interesting.  I'm more concerned about balancing for engine longevity than I am about performance but I think it's all tied together.

Sounds like you got an experienced builder willing to set you up.  It's worth spending time to research what you want.  I'd consider custom pistons and modern ring pack to get the bore size and compression you want.  Also consider a roller cam which allows you to use modern oil which I believe helps fuel economy.   Modern goodies help the FE in mpg.  My 482 gets about what the 352's used to get...around 12.5 mpg highway. 

The 360 often gets pooh-poohed and perhaps deservedly so in factory form.  It can be livened up like any other FE.  And if you're staying 360ish cubes and mid to low range rpms, consider a Edelbrock Performer 390 intake.  Much lighter (easier to install) than a cast iron and makes more power in lower rpm range and lower cube size than the Edelbrock RPM.   

I know Jay linked to the thread locking inserts and I like those for steel and iron.  I like the ones linked below for aluminum.  You'll have to go through the charts to choose the size and thread you need.  McMaster Carr tells you what drill and install tool to use.

If you live anywhere near Blair, I'd consider going there...since it's kinda important to do right the first time.


https://www.mcmaster.com/products/thread-repair-inserts/threaded-inserts-3~/18-8-stainless-steel-key-locking-inserts/https://www.mcmaster.com/products/thread-repair-inserts/threaded-inserts-3~/18-8-stainless-steel-key-locking-inserts/

Yes, I can remove the remainder of the steel insert but the aluminum threads in the head holding the insert are paritaly gone and the head needs welding to restore the missing threads. I've got pictures on my phone but I can't get it to link to my computer so I can't show you the damage.

Sounds like just the threads pulled out with no further peripheral damage.  I don't believe I'd want it restored to the way it was even if they did the work for free...especially if you're not planning to oil through that hole.  For your case, I'd at least investigate key locking inserts and/or find out why they weren't used in the first place.  Honestly may just be my lack of knowledge, but it's a mystery to me. 

Eaton Detroit springs are "boutique" springs for restorers, or desperate antique owners (a very expensive option).

Cutting coils are for desperate 'rodders, with no other options, shade tree mechanics, and low budget dirt track racers. Only cut coils as a last resort.

I tend to agree with you on the Eaton Detroit springs though boutique is not quite the word I’d choose.  I go there when I want springs to last 15 to 20 years.  The aftermarkets  (like moog, mevotech, or whatever NAPA has) I hope to get 5 or so years.   

Each source for springs have their place.

I’m happy with the coils and leafs I’ve got from Eaton Detroit Spring.  They don’t give them away but they’re good. 

Many cars have options to raise/lower an inch or two and some have options for “heavy duty”.

 

Anyone ever seen a cast aluminum block with Glyptal in the lifter valley?  My guess is that you wouldn't want to put it on an aluminum block because they squirm around so much with heat, but that also tells me that with the amount of aluminum blocks out there in extremely high performance/race applications, the paint just isn't necessary. 

Aluminum can be tricky.  I've done pull testing where a formula exceeded requirements on one panel and was complete fail on another panel from the same lot of panels.   I honestly have not been involved with aluminum enough to know why.  A fellow has to be real careful how the surface is prepared.  I just know it made we want to climb a tree and sit in it. 

By surface prep, I mean how the aluminum product is prepared by the manufacturer…not anything the typical person can do at home.