AV gas does not have any deicing additives; that is an old wives tale that refuses to die.  Many years ago, I called Phillips Petroleum and spoke to Clayton Reasor (don't know why I still remember his name after this long) about their racing fuels.  He told me all about the 5 or 6 variations they offered; lead levels, octane levels, etc.  I then asked him specifically if there were any deicing additives or anything else in their AV gas that would cause problems in an automotive engine.  He said no, and as long as you're not getting pre-ignition, it would be safe to run.  Something else to consider is the octane rating method.  Automotive fuels are rated using the average of the research and motor octane levels.  100LL uses the lower of the two.  If it were rated using (R+M)/2, it would be around 105 - 107.

As a side note at this point, I did some poking around and found a nice undamaged Performer RPM intake for sale in California for $180 shipped! Seems like a really good deal! I mean, new ones from Jeg's or Summit are currently $700 dollars. I'll buy it and use it for a future project, don't think I should let it get away.

Brian

Does it actually say "Edelbrock Performer RPM" on the manifold?  The knock-offs look VERY similar.  Is it close enough you can pick it up rather than ship? You know what they say, "If it sounds too good to be true..." Be careful!

Those flow rates look to be very close to a stock CJ head....

Quote from: galaxiex on September 24, 2024, 07:41:32 PM

All C6 from 1967 - up, have "manual 2nd" and will NOT shift to 3rd, if the shift lever is kept in "2".
Even from a dead stop, if the shifter is in "2" the trans is in 2nd gear.
Starts out in 2nd and stays in 2nd.

I believe this may be incorrect.
1966 was the fisrt year for the C6 and it had a single year different valve body and shift pattern, often refered to as the "green dot" transmission.
Park, Reverse, Neutral, 2 (2nd, 3rd only), Drive (1st, 2nd, 3rd) Low (1st only)

1967 saw a change in the valve body and shift pattern to what we pretty much know as the automatic standard of: Park, Reverse, Neutral, Drive (1st,2nd,3rd gears) 2 (2nd,3rd gears only) 1/low (1st gear only)

Some people refer to the 2 (2nd and 3rd gears only as the "Snow" gear)
There was no 2nd gear only selection for a C6.

Cleandan, I believe you are incorrect.  From the owner's manual for my 70 Mach 1, the SelectShift automatic, when placed in the "2" position, starts and remains in second gear.  The C6 in my first car, a 72 Galaxie, operated the same way. 

I believe you will want to put your car in third gear for the test; you want direct drive (1:1 transmission ratio).

Are they 2 1/2 inch?

I believe the thermostat is 2-1/2" OD and the hole in the housing is 2-3/8".

I used an engine pre-luber to circulate oil before firing the engine up.  It looks like a propane tank; put a quart of oil in it, add some compressed air, and hook it up to one of the oil pressure ports.  Open the valve to get the oil going, then spin the engine over by hand.  All of this is after making sure the fuel tank has good gas in it.

There are several youtube videos showing how to do this.  You'll need a vacuum source, such as a Mityvac hand pump.   https://www.youtube.com/watch?v=SZtDhOgdxno