1973 400 wake up

As was stated earlier, 73 was a low compression smog motor. I couldn't (& still can't) afford aluminum heads for my '73 400 Newport, but if I did, my choice would be either 440Source or Edelbrock RPM heads. I went with flat top pistons and shaved heads. I made sure to have the intake manifold shaved at the same time as the heads to ensure the ports lined up right. I also opted for a 383 Magnum cam clone, true dual exhaust and glass packs for that muscle car rumble. My compression is around 10.5:1.

For additional kick at launch, I went with a 10" convertor, a 2.77 1st gear (as opposed to the stock 2.54 1st gear), a 6 row trans cooler and a deep 2+qt trans oil pan (to ensure longevity from the slushbox).

I also installed an Eddy 4bbl & upgraded the ignition to an MSD Street Fire box. I like how it has an adjustable rev limiter. It's a dial, not a "pill" limiter. Mine is set to 5K due to the stock valve springs, don't want to float a valve and blow the motor. It does fire up easier cold and it runs and idles a little smoother. If I was younger and still drag racing, an MSD 7AL would be the ticket, but for every day street driving, this is all you need. Before and after was night and day, it "tamed" the rough cam and gave me back low end power without sacrificing that rumble sound.

When I 1st got it (stock 2bbl), a Prius would embarrass me at red lights. Now, not so much. 4.10 gears would really wake it up, but since I live way out in the sticks (10 miles to the nearest town/gas station) at 8MPG with the stock 3.23 gears is bad enough. Unless I upgrade it with overdrive, shorter gears really isn't a viable option unless my pockets get deeper. For a big heavy car, it's respectable in the way it moves and sounds. It still won't light up the tires (unless the streets are wet), those 275/60R15 Cooper tires have too much grip with the posi I installed, but she doesn't waste any time getting moving from a dead stop.

That's my experience anyway. I built a 400 Magnum package that Ma Mopar neglected to offer.
Interesting. For me, I will stay with the engine and trans as built, since retirement funds are limited, but want to know what you think of the 3.54.....OK, or would you like more. I do not have, nor will I likely pay for suregrip, and just want to change the gear. Obviously no high stall either, but think maybe 3.54, or 3.73.
Adjust the timming ahead about 5 degrees while you are at it and will be good to go unless you get spark knock then back it off some
Adjust the timming ahead about 5 degrees while you are at it and will be good to go unless you get spark knock then back it off some
Advance the timing to what the engine wants, a low compression 400 will want plenty of initial timing(some want 20deg). Then you will recurve the distributor using the initial you found engine happy with and a total of 36deg.