After determining a rusted no#7 intake valve causing 80% leak down. I pulled the heads this past weekend and decided to clean them up and box-em. I found a another matching set of C8AE-H castings from a head porter friend as I'm wanting to keep this motor appearing accurate but would like to make a little more power. So he found a set of custom Ferrea 26* 2.095 intakes locally cheap. Installed, cut the seat to 45* and cut the bowl then blended. Now were setting at a 90% choke (better than the 93.2% in stock config with the 2.030's) and these are the numbers so far @28".

.100   74
.200   167
.300   217
.400   222
.500   246
.550   256

Haven't tackled the exhaust yet. But I see major issues with 3 of the 4 ports having heat risers exiting to the intake and killing exhaust port speed. Talked with Alex at Alex's Parts today and he commented that some old timers had poured aluminum in to seal up the heat riser exits and then blended the ports. I was interested in finding out if anyone has performed this mod and how it worked out?

  Hello I'm Gordon from Va.Beach Virginia,
I bought a 69 S code Mach I a month ago ("my first muscle car") and have been going through a lot of small issues and correcting them as I see them.
      In the pursuit of making my 69 390 run optimal I ran across cylinder no#7 miss-firing at idle only and @ higher rpms it does not. It had lack of power and intermittently an uneven power issue when I first drove it home. I had found the dizzy was coated with aluminum chips inside due to lack of oil making it to the bushing causing the mech advance to drop down and flycut into the housing. After correcting this and replacing a bad vacuum advance with an adjustable unit to boot, the engine ran much better. But no#7 still has a miss @ idle.
        I put my vacuum gauge on it and it read out a very steady 20"and this engine burns no oil upon start up or under accel.

1- Checked for avail kv @ idle and had 25k on no#7 plug wire. (FYI for a test I did hook up 12volts directly to my Pertonix module and got an additional 3k over just using the resistance wire supply)
2- Pulled the plug and it looked fine also compared it to a good cylinder. Note: no oil was on the plug either
3- Performed a compression test and it read out 136psi. I checked #5 and it had 172psi.
4- Performed a running compression test. Result was 62psi (to low)
5- Performed a leak down. Hot engine. Result was 2%@100psi
6- Pulled the valve cover and observed the rockers while the engine ran. Looked good to me comparatively to the other cylinders.

The resulting outcome of leak down test is baffling. I would have expected at least 15-20%. I am leaning to the belief this cylinder either has a bent rod that wasn't caught in a previous repair or has a wrong piston installed. I tried finding compression readings with possible wrong pistons installed online but found nothing. I thought about using a bore scope visually look in the cylinder to see if the piston sits lower than another but I think it's a fruitless endeavor. Any ideas before I pull the head and do a visual?