Looking to buy/build 500-600 fwhp 360

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That compression will work fine on 91, just need to pay attention to the machine work and try to get all the pistons at zero deck so there's decent squish. Also are you getting that 10.7:1 figure from a calculator that includes piston-deck clearance and head gasket bore/thickness or from the chart given by the stroker kit manufacturer? If it's the latter you should calculate the static compression yourself it might come out lower. I wouldn't be afraid to run 10.7:1 on pump gas though especially with aluminum heads.
Well, I bought the rotating assembly so I don't know if I can get zero deck. I'm getting the compression ratio off the Hughes engine web site. I might port the heads and run a bigger roller cam. I don't plan on running nitrous very much, and it's a 4 speed so I can lower the static compression ratio a bit and put in a healthy cam to build pressure. At least I think I can do that.
 
Well, I bought the rotating assembly so I don't know if I can get zero deck. I'm getting the compression ratio off the Hughes engine web site. I might port the heads and run a bigger roller cam. I don't plan on running nitrous very much, and it's a 4 speed so I can lower the static compression ratio a bit and put in a healthy cam to build pressure. At least I think I can do that.

Why lower the compression and use the cam that way?
 
The rotating assembly I bought is from Huges, Hughes 408 lastroker-FHRcast. I haven't selected a cam or carb/intake
 
Why lower the compression and use the cam that way?
I can use a bigger cam when the static compression ratio is 10.5 to 1, or so, I think? I can also mill the heads to build a little static compression back. The ported cc volume on the Edelbrocks will be 73 cc's. Looking for a pair of Trick Flow heads ideally.
 
So my summary of mediocre knowledge is as follows. High cam lobe separation angles good for nitrous, bad for building cylinder pressure.
 
Yes, having a larger chamber is preferable so you can maintain a tighter deck height and have good quench! Sounds like your on the right track.
 
So my summary of mediocre knowledge is as follows. High cam lobe separation angles good for nitrous, bad for building cylinder pressure.
Not necessarily a bad thing. The right cam can give you the best of both worlds. The NMCA stroker I mentioned had a 116 LSA cam and made 768 HP below 7000 rpm and ran 6.04 in the 1/8th in a 3200 lb Mustang all motor. It ran 5.40 on the juice. He actually drove it on the street some and the engine had good street manners. Just needed slicks....LOL
 
JE with a mirrored dish to match the chamber in the head. Top ring was .350 down from the top and the crown was about .400 thick.
 
Well, I bought the rotating assembly so I don't know if I can get zero deck. I'm getting the compression ratio off the Hughes engine web site. I might port the heads and run a bigger roller cam. I don't plan on running nitrous very much, and it's a 4 speed so I can lower the static compression ratio a bit and put in a healthy cam to build pressure. At least I think I can do that.

Attaining 'true' zero deck on the pistons would require measuring what the current block deck height is, the older LA engines were pretty bad about the decks being taller than spec but a Magnum block is going to be a lot closer to what it's supposed to be. The kit you got has a note at the bottom of the page, "calculated using a zero-deck engine with .030" overbore and .040"-thick head gaskets". When you go and install the pistons they may end up being .005-.010" below deck or more which will affect (lower) your actual static compression measurably.
 
Attaining 'true' zero deck on the pistons would require measuring what the current block deck height is, the older LA engines were pretty bad about the decks being taller than spec but a Magnum block is going to be a lot closer to what it's supposed to be. The kit you got has a note at the bottom of the page, "calculated using a zero-deck engine with .030" overbore and .040"-thick head gaskets". When you go and install the pistons they may end up being .005-.010" below deck or more which will affect (lower) your actual static compression measurably.
Surely there must be a way to check for deck height before assembly. I'll have to do that, because we might as well try for maximum compression on pump gas. I've kind of resigned myself to milling the cylinder heads to reduce the chamber volume. I don't think milling heads is very expensive. We can just mill the block to make sure we have zero deck height, but the kit does not show flat top pistons. So how do you get a zero deck height when the pop up piston is sticking up proud to the block?
 
Zero deck applies to the quench portion of the pistons, not the domes. And since you have domes, you'll need to stick a piston in a bore and cc it to confirm the dome volume to calculate your compression more accurately. You may also need to cut valve reliefs so you need to cc the domes once all the piston work is finished.
 
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Surely there must be a way to check for deck height before assembly. I'll have to do that, because we might as well try for maximum compression on pump gas. I've kind of resigned myself to milling the cylinder heads to reduce the chamber volume. I don't think milling heads is very expensive. We can just mill the block to make sure we have zero deck height, but the kit does not show flat top pistons. So how do you get a zero deck height when the pop up piston is sticking up proud to the block?

Unfortunately it's tricky to do without the crank and at least one piston and rod installed. Something to consider is the shape of the combustion chamber, quench distance and head material have more effect on detonation resistance than static compression ratio alone. You can have an engine with 9.5:1 compression with open-chamber iron heads and it'll ping on 91 octane but one with 10.5:1, decent quench and aluminum heads will be fine (NOT including the effect of valve timing on dynamic compression).

My understanding is the Icon 9978 pistons aren't "pop-up". It has a quench ring around the outer edge with a slight dish in the middle and some good-sized valve reliefs. The quench area is intended to be flush with the top of the block deck so no part of the piston protrudes out the top of the cylinder unless you intentionally mill the decks for it. That type of piston on a stock-stroke 360 would be in the mid-9s for static compression but the 4" stroker crank increases that quite a bit just from the longer stroke length.
 
Update, I have purchased a set of Icon flat top forged pistons. The original pistons had a zero deck quench area but were slightly dished. I did not want to mill the heads 060 to get 10.1 compression. Now i'm on the other end of where I want to be. The compression ratio will be about 10.9. I can mix a little race gas (ugh). I don't know if putting a little thicker head gasket will get me to 10.5 How about porting a little more to get both better flow, and increase chamber volume? The other thing I thought about is using the box I am going to install to retard timing while on nitrous and use it to retard timing when I am running pump gas. Or, can I get away with 10.9 at 3200 feet on 91 octane? I need an anti knock sensor...
 
Update, I have purchased a set of Icon flat top forged pistons. The original pistons had a zero deck quench area but were slightly dished. I did not want to mill the heads 060 to get 10.1 compression. Now i'm on the other end of where I want to be. The compression ratio will be about 10.9. I can mix a little race gas (ugh). I don't know if putting a little thicker head gasket will get me to 10.5 How about porting a little more to get both better flow, and increase chamber volume? The other thing I thought about is using the box I am going to install to retard timing while on nitrous and use it to retard timing when I am running pump gas. Or, can I get away with 10.9 at 3200 feet on 91 octane? I need an anti knock sensor...

I think it'll be doable but you'll just have to pay close attention to quench distance and little things like smoothing down any sharp edges in the combustion chambers and piston heads as well as run a cam with the right valve events to bleed off some cylinder pressure in the lower RPMs. I would run whatever thickness of head gasket gives the optimum piston-to-head clearance and not for reducing static compression.

I ran a 360 at 10.5:1 on 91 pump gas for years, it was "borderline" but in hindsight I could have done a few things to make it better. First off the cam I was running was way too small and made way too much cylinder pressure, it could have used quite a bit more overlap and a later Intake Valve Closing point. I also found out recently that the timing light I've been using for the past 8+ years reads about 4 degrees lower than actual so when I was setting my ignition timing it was always advanced 4 degrees more than I thought, for that reason I never retarded the timing as much as I thought I did and it pinged a lot. And lastly I was using factory iron Magnum heads; aluminum heads likely would have eliminated all the pinging issues with how it was on the edge but not over.

My current 360 is 9:1 static compression and has ported Edelbrock heads and a custom-grind hyd roller cam from Racer Brown (not huge, around 223 degrees duration at .050"). I had it run on a chassis dyno and found optimum ignition advance at 40 degrees total and it runs on low-octane regular gas all day long, never once heard it ping even on the hottest days.

One thing to note however I am at 5000' above sea level so about 2000' higher than you, not a big difference but still something. Hopefully all of that was helpful and not confusing lol.
 
Surely there must be a way to check for deck height before assembly. I'll have to do that, because we might as well try for maximum compression on pump gas. I've kind of resigned myself to milling the cylinder heads to reduce the chamber volume. I don't think milling heads is very expensive. We can just mill the block to make sure we have zero deck height, but the kit does not show flat top pistons. So how do you get a zero deck height when the pop up piston is sticking up proud to the block?
To measure deck height use a 12" digital caliper. Measure from the top of the main bearing bore to the deck. Subtract 1/2 of the diameter of the main bore and you have your deck height.
 
subtract or add half the diameter of the main bore. if you have an upper bearing shell in the bore can you just use 1/2*3.58 or 3.31" ??
 
subtract or add half the diameter of the main bore. if you have an upper bearing shell in the bore can you just use 1/2*3.58 or 3.31" ??


You use 1/2 the diameter of the housing bore. No bearings. But you have to know the exact diameter as there is a small tolerance.
 
I've been thinking about how much to worry about the compression on premium pump gas. I have a 350 chevy iron headed stock engine in a truck with 10.25 compression. Actually, it is bored 040 over so it is slightly higher. It was a 300 hp engine out of a corvette. I never ping and have run the engine for years without issues. I have heard aluminum heads are good for about 1 point in compression so I should be good up to 11.25?
 
I've been thinking about how much to worry about the compression on premium pump gas. I have a 350 chevy iron headed stock engine in a truck with 10.25 compression. Actually, it is bored 040 over so it is slightly higher. It was a 300 hp engine out of a corvette. I never ping and have run the engine for years without issues. I have heard aluminum heads are good for about 1 point in compression so I should be good up to 11.25?
how premium is the premium ? my car would ping on 91 octane 11.2 ran fine on 93 octane with alu heads you might dot on 91 if the tune is spot on
 
how premium is the premium ? my car would ping on 91 octane 11.2 ran fine on 93 octane with alu heads you might dot on 91 if the tune is spot on
It's 91 octane but I'm at 3200 feet. I'm going to be running an MSD ignition which will allow me to easily retard the timing on a hot day, etc.
 
Do BluePrint crate engines come with any porting on their cylinder heads? I could not get trick flow heads, so I just ported some Edelbrock cylinder heads. The carb came today, an 850 Holley. I guess I'll get 4 mpg, oh well.
 
Do BluePrint crate engines come with any porting on their cylinder heads? I could not get trick flow heads, so I just ported some Edelbrock cylinder heads. The carb came today, an 850 Holley. I guess I'll get 4 mpg, oh well.
you should get 10 miles per gallon , but it will be fun
 
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