You'll need to get everything balanced to use the 410 crank along with the flywheel and harmonic dampener. Since you have to do that, have your machinest deck the block about .010-.020 and the heads milled. Then you can use .020 steel shim gaskets. Depending on the cam you get you can bring the DCR down to a manageable level to run 87 octane gas with 10.5 CR. If you can keep the squish down below .050 you'll have a nice running engine. If you don't go too radical a cam you can still have 13 inches manifold vacuum at idle that will run a 8" dual diaphragm power brake booster. Just my take.

Thx gents, all great info.

I think mine is fairly similar to yours Jim. I told the builder it was just for fun, and that I wanted a tire spinning street car. It's just a fun Ratrod type T-bird that I cut a hole in the floor for a 4 speed. I fell in love with the idea of a 390 with a longer stroke after reading a bunch of stuff on the interweb. They all say torque is what'll move a heavy car. The builder told me that it was basically a 66, 67 Merc 410. It was bored .030. Has c4ae heads with CJ exhaust valves (stainless steel) and comp springs. I didn't know anything about "shimming" so I asked the builder after I read it on the build specs. He said something like it makes all the valves perform the same (evenly) and will help stop valve float. He used a CJ cam. It idles OK at 650 rpm. The CR is 10.5 and runs fine on 91 octane. I had found an RPM Performer intake. I put a Edel 750 with the appropriate jets and metering rods for our altitude. I also have FPA headers, they are the only ones I could find for a 59 T-bird - they were pricey but really well made. He said it would probably be in the 375 to 400 hp range and torque would be in the 450 range. The car weighs 3800 without me. 

What does .050 quench and 7.5 DCR mean? Also, what is desktop dyno? I'm guessing that's software for estimation purposes?

My rearend is a 3.89 one wheel turner. Once I break in the motor and clutch I will see how the wheel spins and hopefully get a limited slip 3.50 to 3.70ish pumpkin. I want to be able to drive it 90 miles to Albuquerque sometimes. I might buy a used trailer and tow it. If I do I'll go with a lower rearend.

I had a hard time setting the timing and I'm still tuning it. The builder told me the timing should be about 10-12 and that it should never go over 38 total. I think I might start a whole new thread on that when I get some warmer outdoor temperatures and can work on it.

thx, Dave J

Dave J,
    You need to figure out first what you want your car to do. With a four speed transmission you have to make a choice. When I restored my 57 Fairlane the first thing I did was design it. I wanted drag racing fun AND touring economy and smoothness. That's why I went with a Tremec TKO 600 with a 3.50 Tru-Trac. I cruise at 65mph and 1850 rpm getting 16 mpg and I can't put big enough tires under my car to keep it from spinning when I get on it. My advice to you with a 4 speed is to make a choice. Since I enjoy driving my car and going on trips I'd choose a 3.25 rear gear ratio at the most. But, if you like cruising down the interstate with your engine turning 3000 rpm, go with a lower gear.
Quench: That's the distance between the top of the piston and the bottom of the head with the head gaskets installed. You can go down to .040 at a minimum and .050 at the most to achieve a more complete gas atomization that will enhance the combustion in the cylinder and lower your needed octane level per compression ratio used. In other words it will help minimize spark knock when using lower octane fuels with higher compression engines.
DCR: Dynamic Compression Ratio is the actual compression ratio the engine sees. You need to look this up on the internet to fully understand it but in summary it's the compression ratio with stroke measured after the valves are fully closed on the compression stroke.
On both my 406 and 410 the Quench and DCR were designed into the engine before the cam, pistons or head gaskets were chosen. That's why I can burn 87 octane with a 10.5 CR, .042 Quench , 7.6 DCR 406ci engine and a 9.5 CR, .050 Quench, 7.5 DCR 410 ci engine.
Timing: My 410 ci engine has an initial timing of 14 degrees and a total of 38 degrees. The 406 ci had to be set at 17 degrees initial with a total of 34 degrees. The 406 had to have an ignition system that retarded the timing 5 degrees to enable the use of a stock starter though. You can't start a FE engine at 17 degrees, not very well anyway. I hope this helps.
PS The 406 engine was initially designed to drag race. I built the engine before I got the car from New Mexico. The car ended up being too nice to cut up so I changed the ring and pinion in the 3.50 Tru-Trac I'd previously bought to a 2.75 gear ratio. I also had to change the cam in the engine and turn the vacuum screw back in the Jay Broader transmission so it wouldn't jerk your head off during slow speed shifts. I get 14 mpg with that engine and I cruise at 2150 rpm at 65mph. I had to make a choice with that car because I didn't have a transmission versatile enough for touring and drag racing. I can barely spin a wheel with that car (406).

Maybe fiddle with the PCV choice to pull a bit more crankcase vacuum?

  I installed  a new PCV valve today. It came in a kit that was marketed by C.R.A.P. I ordered the kit so I could install a PCV valve on my 63 with the 406 and aluminum intake. They advertise the PCV valve as that of the original specs of a 427 Ford engine. It's a nice kit and I bought another PCV valve just like the one that came in the kit, it only cost me three bucks. I took the old PCV valve out of the 57 with the 410 that was leaking and it barely rattled. The new one rattles big time. The new valve is a Fram FV184 and I can't find the specs on it but it's made for a chevy V8 up to 454. I need to find a place on the web that gives the specs for these PCV valves. I hope this helps with the oil leak because it went all summer without leaking and just started this last 1000 miles or so.
12/04/2013 
   I found out by searching the internet that the FV184 PCV valve has a spring in it that takes 117 grams of pressure to compress the internal spring .300", while the FV191 PCV valve has a spring that takes 95 grams of pressure to compress its' spring .300".

Both my cars (406 and 410) have cams in them that give me 13-15 inches manifold pressure at idle. I compared both PCV valves while monitoring a vacuum gauge. Both PCV valves gave me @14" MP at idle and 20' MP at @1500-2000 rpm. The only difference was the PCV valve with the light spring (FV191) was completely closed at idle and the PCV valve with the heavier spring (FV184) rattled constantly, indicating it was closing/opening at a very fast rate. I used the FV184 in both engines. 

In a word....don't. Those products IMHO are fine for a old leaky engine in a grocery getter. Live with it, I say.

How come I had an idea that would be the answer. Done, If Brad Penn 10W30 doesn't fix it, it won't get fixed.

I looked up the Tremec Website and they now suggest Dextron III/Mercon. I had plenty of that so I went out to the hanger, drained the Amsoil out and installed the Dextron III/Mercon ATF. I'll see what happens. As a side note, I don't think I lost very much fluid. It just looks like a lot on the floor.
 If that doesn't do it I'll probably pull it this winter and check the front end. I plan on taking it easy on the car the rest of the year anyway. Jim  PS  The corvette website had good information. Thanks guys.

Guys,
   Have any of you with a Tremec TKO used a elbow and small filter for the top oil fill plug on a Tremec. The reason I'm asking is that on my application with the 57 Fairlane my transmission vent is right up against the transmission tunnel of my car. I've noticed oil seeping from between the bell housing and transmission like a seal is leaking around the output shaft and I just wondered after turning 5000 rpm on the race track if I may be building up pressure inside the transmission and forcing oil out. This Amsoil transmission fluid I'm using produces a quieter transmission but I wondered about heat and pressure. I've never seen this oil drip before when using GM Syncromesh transmission fluid. If it is a vent problem I thought a elbow and filter may cure my problem. ANYONE BEEN THERE BEFORE. Thanks, Jim  PS. Transmission has about 50K miles on it now.

Jay and Machoneman,
   I use 87 Octane gas from the cheapest place I can get it. When I designed the engine I purposely chose compression, quench and cam to get a low DCR. I'd like to try racing gas anyway. I'll run the tank lower next time before I take it racing and try buying some racing gas. Thanks for the possible explanation. Jim
PS. I do use a 1/4" hard rubber carb spacer made for the 750 Holley.

Well, I like to beat my car to death trying to figure out how to drive it Friday. I ended up using 28lbs of air in the rear. Leaving the line with it revved to 2000rpm and shifting at 5000 rpm. By shifting at 5000 I wasn't spending time squealing the tires in second and third. It just went. 14.3 ET @ 98 mph. Everyone was complaining because of the humidity. So, without the humidity I figure I've got a 14.1-14.2 car with street tires. I'm happy. Jim
 PS. The temp was 90 something Friday and I ran 5 times ( about 30 minutes apart ) The first run I pulled all the way through the quarter, Second run the same. Third run it fell on it's nose once, Forth run it fell on it's nose about two times, Fifth time it stumbled all the way through forth gear. Came back Saturday and didn't even run during time trials. Threw a dial-in on it, took it down cold for eliminations and it ran great. I bogged coming off line but it pulled great.  Let it cool down two hours for my second round of eliminations and it went through really strong again. In fact it was so great that I broke out by .3 seconds. And I had dialed in my best time on Friday.