A forged 360 Mag piston that comes in around 8- 8.5:1?

[turbovan]

Did you happen to cut one of those apart and measure crown thickness?

Not my piston/pictures. I don’t believe I have pictures of mine which were not so dramatically disfigured, but still trashed.

 

[TT5.9mag]

Not my piston/pictures. I don’t believe I have pictures of mine which were not so dramatically disfigured, but still trashed.

I was surprised when I cut the stock mag pistons apart to measure them.

 

[Michael Harrington]

I plan to be able to run 93 octane which is pump gas here. Build will obviously be very mild. My goal: Gutsy punchy RELIABLE street only engine in my 95 2wd Dakota. No strip. Summer toy. Edelbrock 650 cfm carb (AVS Series) 727 with RMVB- appropriate stall, and eventually 3:55ish ring and pinion. 1st gen Magnum larger outlet exh manifolds with dual exhaust and inexpensive Walker Turbo mufflers.

 

[TT5.9mag]

I plan to be able to run 93 octane which is pump gas here. Build will obviously be very mild. My goal: Gutsy punchy RELIABLE street only engine in my 95 2wd Dakota. No strip. Summer toy. Edelbrock 650 cfm carb (AVS Series) 727 with RMVB- appropriate stall, and eventually 3:55ish ring and pinion. 1st gen Magnum larger outlet exh manifolds with dual exhaust and inexpensive Walker Turbo mufflers.

View attachment 1716440940

Cool. I think you’re putting together a nice little fun streeter. My advice is the same as above. Use the stock magnum piston and bottom end, put good hardware in it, rod bolts and main bolts. It’ll be more than sufficient for what you’re doing. If you want to do machine work and have to have a forged piston, do some math to set the compression ratio where you want it. Rarely does an off the shelf piston make the compression number they advertise. You can safely target 9.2-9.5 on 93 if you know how to set the timing up. In fact I wouldn’t want to build it at 8:1 it’ll be lazy off boost and that’s no fun in a street car.

 

[Michael Harrington]

Thanks TT5..9. If my core needs an overbore what cast or hypereutectic pistons are equivalent in quality and available for replacements?

 

[TT5.9mag]

Thanks TT5..9. If my core needs an overbore what cast or hypereutectic pistons are equivalent in quality and available for replacements?

I certainly wouldn’t consider aftermarket cast pistons, hypereutectic I might consider if that’s all I could find, but if you’re in there boring and replacing stuff you might as well use a forged piston. I use Mahle whenever I can. But I’ve also used DSS and Icon with no problems

DSS Racing K2-6353-4000 D.S.S. FX-Series Forged 2618 Alloy Piston and Ring Kits | Summit Racing

 

[Michael Harrington]

I like the price of the DSS piston set .

 

[TT5.9mag]

I like the price of the DSS piston set .

That’s a 360 piston with a 1.667 comp height. I used it as an example. If you use that in a shorter deck magnum you’ll have the piston out of the bore and lots of comp. You’ll have to look up mag pistons in 1.605 comp height.

 

[Michael Harrington]

That’s a 360 piston with a 1.667 comp height. I used it as an example. If you use that in a shorter deck magnum you’ll have the piston out of the bore and lots of comp. You’ll have to look up mag pistons in 1.605 comp height.

Got it

 

[TT5.9mag]

Got it

Call the manufacturer of whatever piston you choose. Most piston companies will make one or two changes to a shelf piston before they consider it a custom piston. Ask em if they can move the compression height around to where you want it. Be aware though at 1.605 the stock magnum pistons (that I’ve measured) come in at 050-055 below deck on stock magnum blocks.

 

[turbovan]

That can’t be right? 1.667 comp height is zero deck on a stock stroke magnum. That’s exactly what I’m running.
(3.58/2)+6.123+1.667
Magnum deck height is 9.58

 

[TT5.9mag]

That can’t be right? 1.667 comp height is zero deck on a stock stroke magnum. That’s exactly what I’m running.
(3.58/2)+6.123+1.667
Magnum deck height is 9.58

I think it’s right. Did I fubar some numbers?

 

[TT5.9mag]

That can’t be right? 1.667 comp height is zero deck on a stock stroke magnum. That’s exactly what I’m running.
(3.58/2)+6.123+1.667
Magnum deck height is 9.58

It’s correct. The only discrepancy Ive found is the compression height listed as 1.612 on multiple pages. Either way when using an LA piston (1.667) in a mag block it will be proud of the deck a bit. .008-.011 with nominal numbers.

 

[MiradaMegaCab]

Lowest off the shelf I've seen is the Carillo Bullet pistons P/N: BMR-4200-030.

BMR4200-030 CP Pistons, Bullet SB Chrysler, 4.030 Bore, 9.0:1

1.645CH
9:1CR @62cc head chamber

OP, how many CC’s are your heads?

 

[TT5.9mag]

BMR4200-030 CP Pistons, Bullet SB Chrysler, 4.030 Bore, 9.0:1

1.645CH
9:1CR @62cc head chamber

OP, how many CC’s are your heads?

That’s a great piston. Wonder what their opinion would be for mild boosted (5-15psi) applications.

 

[DNasty777]

The CNC motorsports link says only for NA applications, but I don’t recall seeing any notes like that in the Carrillo catalog. Might be worth a call.

 

[MiradaMegaCab]

A 142 blower on a 360 will be lucky to maintain 5PSI of boost.

 

[Michael Harrington]

BMR4200-030 CP Pistons, Bullet SB Chrysler, 4.030 Bore, 9.0:1

1.645CH
9:1CR @62cc head chamber

OP, how many CC’s are your heads?

Im looking at running ported stock Magnum heads

 

[MiradaMegaCab]

Hmm, why not just bolt the blower onto a stock Magnum engine?

 

[Michael Harrington]

Hmm, why not just bolt the blower onto a stock Magnum engine?

I could do that but I actually want to spend some money on a nicely done 360 engine. At 56 with my kids grown and gone and now some disposable income I'd like to do what I've not been able to afford to do in the past, and I want to do it right. I'm not afraid to spend some $$. Plus the 318 mag currently in may Dakota has 235,000 miles on it. The core 360 Mag I obtained is out of my brothers Ram and has 300,000 miles on it! It still ran good but consumed oil. Got it for free.

 

[TT5.9mag]

I could do that but I actually want to spend some money on a nicely done 360 engine. At 56 with my kids grown and gone and now some disposable income I'd like to do what I've not been able to afford to do in the past, and I want to do it right. I'm not afraid to spend some $$. Plus the 318 mag currently in may Dakota has 235,000 miles on it. The core 360 Mag I obtained is out of my brothers Ram and has 300,000 miles on it! It still ran good but consumed oil. Got it for free.

I know you’re doing a mild build, but for not very much more money you could get a complete stroker rotating assembly from scat, balanced and ready to basically set bearing clearance, and drop in. Put your ported magnum heads on it for now and have plenty of room for improvement later if you choose. It’ll be a torque monster. The blower and heads become a big limitation at that point though. Down the rabbit hole we go.

 

[Michael Harrington]

I know you’re doing a mild build, but for not very much more money you could get a complete stroker rotating assembly from scat, balanced and ready to basically set bearing clearance, and drop in. Put your ported magnum heads on it for now and have plenty of room for improvement later if you choose. It’ll be a torque monster. The blower and heads become a big limitation at that point though. Down the rabbit hole we go.

I have already bought the intake from Australia, a 142 Weiand from a member here AND had that Weiand rebuilt with the lobes machined and Teflon strips installed . I want a fun responsive engine without a big camshaft. Plus I think small Roots superchargers are neat. I know BIG power is not made with tiny blowers and I'm fine with that.

 

[TT5.9mag]

I have already bought the intake from Australia, a 142 Weiand from a member here AND had that Weiand rebuilt with the lobes machined and Teflon strips installed . I want a fun responsive engine without a big camshaft. Plus I think small Roots superchargers are neat. I know BIG power is not made with tiny blowers and I'm fine with that.

You know what’s neater than small roots blowers?

Giant roots blowers.

 

[MiradaMegaCab]

 

[Michael Harrington]

While a Big Blower is not in the cards the manifold I just got from MaX Wedge looks like it will accommodate a slightly larger unit like a 174. Another company in Australia makes a plate to install a 177 on a manifold designed for the 142/144. But honestly I truly will be happy with 400 HP. A non temperamental easy reliable 5700-6000RPM max type 400hp.