Hello everyone,
I rescued a 1965 Imperial from a barn in Western Illinois last Summer and it has turned into quite the fun project. We drug it home, installed a battery, fogged the cylinders, and the old girl fired right up. It is a rust free car with 105K miles on the odometer and is equipped with a 413 cu and 513 casting closed chamber heads. I would love nothing more than to leave the 413 in the car and just drive it around but there are just too many leaks due to aging seals. Ultimately, it will have to come out for repair. My concern is that the motor will need to be bored and from what I have gathered... that can be quite the deal with a 413. The car was extremely well maintained during it's use until it hit the barn and I have 20+ years of receipts... but nothing documents any signs of head or engine work. The long block is still relatively clean despite leaks, doesn't have any sludge, and for some reason the heads are bare metal while the rest of it is painted a turqoise color. My first suspicion would be that valve seal work was done. If i am to go through the effort to yank a motor I would prefer put it back in with some added power to turn a few heads. It doesn't have to scream but max HP/Torque in the 3500-4500 RPM range would be best. Here are some options i am tossing around so please feel free to chime in with suggestions....
1. Pull 413 as is, rebuild it with a Cam/intake/carb
2. Buddy has a 440 shortblock for $300 that is in good shape, can be polished and re-assembled, and comes with a set of 975 heads. Add mild cam/intake/carb.
3. Put the 516 heads on the 440 with mild cam/intake/carb.

Thanks!
Andy

Is it worth punching out the exhaust valves on the 516 heads at this low of an RPM?

 

 

The 516 heads will take the stock 440 valves but the ports are smaller than the 915 or later heads. Since all 413 heads were closed chamber I wouldn't put open chamber heads on it. 413 pistons choices are limited also.

The 440 and 413 have the same 3.75" stroke so I'm thinking they should both have the same low end grunt.

 

My 2 cents..... After having a 1964 New Yorker with a 413... I would rebuild the 413 add a cam and a 4 barrel intake. and bump up the compression. Dont go to big on the cam. These things where "Stump Pullers" is stock trim... Great running engine... But if your budget will not let you do the up grades or a rebuild... Stuff in the 440 as it is and rebuild the 413 later....
I know my hauled azz in the New Yorker.... Keep us posted on what you do... Great cars to drive and a smooth ride... Wish I had mine back.....

 

I have always thought of the 413 as a somewhat magical engine -- and almost a unicorn today! I'm with Hog, rebuild it and cam it and run that monster if you can.

 

Very nice looking!

 

I think I would stay with the 413, not knowing what compression ratio the 440 has it could be below 8.0 to 1. The 413 compression ratio will make up the CID deference of the 440. A cam with less than 220 duration @ .050 lift a decent aluminum two plane intake and 750 vacuum secondary carb. Convert to electronic distributor and dual exhaust.
Use the 516 heads but put the 440 valves in the with a clean up of the bowls and runners. If you use the 440 block use the heads of the 413 to increase compression.

 

Thanks for the replies guys. I like the idea of using the 516 heads and punching out the exhaust valves. Are there any differences in the 440 and 413 block deck heights and can I get back to the 10:1 compression ratio by using the closed chamber heads on the 440 block?

 

The 413 and 440 are both raised blocks so there deck height is the same. I would try to achieve between 9-9.5 to 1cr. using 440 valves it the 516 heads withstood work under the valves to unshroud the valves will also help. If you can find a set or hp exhaust manifolds then a 2.5 exhaust system with a cross over or x pipe. A rear axle gear of 3.25 or 3.55 will help it get moving and still have a nice hyway manners.