360 LA Build Suggestions

I have a 73 360 in my 69 Dart that I plan on upgrading. It was redone about 10 years ago and has roughly 10k miles on it. It was .030 over with all stock bottom end, cast crank internally balanced, stock rods and flat tops about .110 in the hole. Cylinder walls still have cross hatches and no ridge at the top. I do have a set of 915 J heads w/2.02's that I plan on installing. It will be strickly street driven and may see some time at the track. My goal is @400hp on pump gas. It is a 4 speed w/3.55's.

Would like some suggestions on the build and may be open to a 408 stroker.

Thanks in advance.

for sure stroke it. 4" cranks adequate for moderate performance are reasonable these days. No one I have ever spoken/dealt with that has went this route has ever regretted it (& they say they would never go back to 360 cubes). EQ mag heads.

First question: what's the budget? Second question: are you willing to redo the short block?

At .110 in the hole with open chamber heads the compression will be extremely low. As mentioned, stroke it if it fits in your budget. I would forget about the 915 heads. Open chamber really kills it and without any additional work 2.02 valves will gain you almost nothing.

A good set of heads and a cam change will get you close to your HP goal, but a stroker motor will give a broad flat torque curve. For a 100% street machine, torque is King.

You can build a 400-450 hp 360 with the stock crank and stroke for 3500.00 in parts. No need to get crazy and stroke it. In my opinion it's not worth the hassle. You won't get any more power out of it for what you want.
Stock bore block
KB 10.5 to 1 pistons
273 rods and no you don't have to balance anything
your heads
Purple shaft 508
adjustable rockers
windage tray
single plane edlebrock intake
750double pumper holley, you will need to put bigger jets and squirter in it
preformance dist
I've built 4 or 5 of these that are still running today after several years of use and abuse. The first one I built made 434hp at the crank, didn't balance anything and no shakes. It regularly seen 7400 rpm shifts and is still a beast on the street. ran 12.40's on street tires, 904 and stock convertor and 3.91's

JMO,

Do some port work to the heads so you don't have to go stupid big duration on the camshaft. Having a 4 speed makes things easier with bigger duration cams as you don't have the issues with in/out of gear as with an auto car.

No need to stroke the engine if you are looking at 400hp. 400hp is not that hard to hit a 360, getting air IN is the issue and heads are the restriction.

4" crank will allow you to keep your 3:55's and still have nice power and torque for street driving.

408 Requires minor notching to the bottom of each cylinder wall for rod bolt clearance. Do it yourself, or pay a machine shop to do it.

408 = New shorter pistons for the longer stroke.

408 = New balance job. External is cheaper than internal.

For the money, you are probably better off getting a set of Edelbrock aluminum heads . . .

Edelbrock heads out of the box would be better than the iron heads, but a dished piston at, or slightly lower than, deck height would be best for quench.

One of the best engines I ever had was the Mopar Peformance 360 crate engine that was rated at 300hp/375tq. I wish they could still offer that engine. Smooth idle cam, roller setup, and obviously underrated in both hp and torque, according to seat of the pants and dyno tests in magazines. The assembly quality was questionable but what a great engine! I'm sure those specs are still available online. I'd love to build one again. 360 block, magnum heads, M1 intake (I might consider trading the intake for a air gap).

I had two of those and they made great torque yet smoooooth idle, which made great sleepers in my old boxy Diplomat Police cars. In my Dippys, with 3.23 gears, sure-grip rears, 235/70/15's and weighing in at 3850 pounds, it would roast the tires all day long if I wanted to, and pulled hard past 100mph when I wasn't comfortable pushing the car anymore.

You're missing only two things from achieving your goal: Flow and compression.

You have already spent $$ on the block, crank and rods, replace the pistons with some that are same or less weight than you have now so balancing is easy if the weights are different. compression height should put piston at or near zero deck.

Purchase those pistons AFTER you buy a new set of smallblock Sidewinder heads. Get the pistons so you have roughly 10.5:1 compression.

Everything else remains the same.

R.

Thanks for all of the input guyz. I'd like to keep the budget under 2k if possible. Heading to the machine shop this week for them to check out the bottom end. Based on that, I'll decide on what direction I'll go w/the heads. Zero deck or just below is the goal but I still will need a cam. I currently have a Weiand Action Plus w/a 670 Holley Avenger and TTI 1 5/8 headers. I'll probably need to step up on the intake. Any suggestions?

If you can get .040" quench & maintain an acceptable SCR for your choice of octane I definitely would. More power/more ping resistance/less advance needed.

400 hp @ 360 cubes?
Copy the 360/380 create engine.
Which dynos over 400hp.

Performer RPM on the intake manifold.

Yes, that was a good one too, along with the one I mentioned if you want something smoother idling, more affordable, and more sleeper-ish and stock sounding.

You can get real close with a cam as small as a comp xe268H or Voodoo 268 as long as the heads flow well in the lift range.

If you have some time to run a grinder, there are a bunch of articles, how to, on getting J heads in shape to flow 240+ at .500 lift. That's enough air from the heads to make 400 hp without going crazy on a cam, losing drivability.

An Air gap, RPM performer or LD340 would be good for an intake. Opening up the port window on the Action Plus would be a good start with a grinder. I'd look for the ede intakes. Sell the action + for funds.

Quench with a zero deck flat top piston and J heads? Good luck with that!

my two main concerns would be:

a flat top piston very near zero deck.

a newer closed combustion chamber like the edelbrock/sidewinder/promaxx heads...
http://www.jegs.com/i/ProMaxx-Performance/723/9360/10002/-1

Yes, I agree. I would choose a similar Comp cam and use the RPM. If I had the cash, I’d also use the rpm heads with some minor work done to it as well.