1957 365" engine upgrades? Who has done them?

Started by chelonian, September 10, 2022, 10:58:27 AM

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Folks, Has anyone been able to boost performance on their 365" engines? I was considering the Holley Sniper fuel injection upgrade. Also considering an electronic distributor upgrade so i can open the plug gap a tad. Maybe better plugs too. ANyone done any of these, or other things? Thanks all.


In 2013 I used FAST fuel injection. Also has pertronix.

 I accomplished a huge weight savings by going with modern alternator,  HVAC, power steering and braking systems.

Marriage of the transmission control rod at the carburetor was challenging.

Art Gardner CLC 23021

For these old Cadillacs, I have done a few things with good success:

Pertronix ignition module, wires, and coil.  This produces a hotter spark, allowing one to open the plugs from .036 to .040 or so.  More power, fewer misfires, smoother, easier starts.  Plus, no more points to maintain.

PowerGen alternator that looks like a generator and fits on the stock bracket.  More voltage, more consistently.  Better lighting and fewer misfires at idle.

Throttle body fuel injection to replace the carb.  Better throttle response, more power, lower exhaust fume levels, better economy.  Instant starting.  No more vapor lock ever.  Fairly straightforward.  Trickiest thing is to create a linkage connection on the throttle body in the same place, at the same radius, and the same angle as the TV rod connection on the stock carb.  If you do that, it will allow the Hydramatic to shift as if it had the stock carb.  Not super difficult, but does require that you pay close attention to what you are doing.

If you want to stick with carb, get Daytona Parts Company to restore your carb. Then install a robust Edelbrock pusher e-pump (about $200) back near the tank.  The one with a built-in adjustable pressure regulator.  Set the pressure to about 5.5-6.0 psi.  Remove the mechanical fuel pump (or just the rod under it!).  This will eliminate heat-related lean out, which is a source of much of our performance issues, including vapor lock.

If rebuilding the engine, have it "blue printed" and precision balanced, like they do for race car engines.  It will make the thing run much smoother and will produce a little more power.

On the single exhaust cars (49-51), I use a slightly larger exhaust pipe (2.25" dia. vs 2.0") for easier breathing and more power.
Art Gardner

1955 S60 Fleetwood sedan (now under resto)
1955 S62 Coupe (future show car? 2/3 done)
1949 S60 Fleetwood sedan (restored 30+ yrs ago)
1958 Eldo Seville (2/3 done)


They were selling cams for these, but I don't know the status of that.  ISKY supplied them, they were in some of the rebuild kits. They probably will grind you one if you ask them nice with a few US legal tneder.  I tried to locate one, but never did find one, ex kit, before we had to go down.  I had a new stock cam so we used that.   
Beyond that I opted to go with tripower, more for looks than HP.  We dynoed the rebuild and it ran pretty flat at 300 above 4500 without advance hooked up, so you can play with the too, if access to a distributor machine.
I guess you can go with aluminum pistons and stroke it to 390.  I'd not increase compression much, it's 10.5 stock.  If you went to turbo or boost, then need to back off of that.
I don't know if the old hydramatic is up to too much more HP, so you have to consider all the components not just the motor or you break stuff.


You can get performance cams for these engines on eBay still.
-----Dan Benedek
'57 Cadillac Sedan Deville 6239DX
'81 DMC DeLorean


I got myself a Cadillac but I can't afford the gasoline (AC/DC Down Payment Blues)

1961 Series 62 Convertible Coupe http://bit.ly/1RCYsVZ
1962 Coupe Deville