The BIG 360 rethink

Bruceynz

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Hi Guys,

After the serve bashing I got from my ideas to improve my car "Project Tire Fryer" and after buying some XXX302 heads/cam/carb and importing to NZ I have sold all that stuff in NZ now and starting again. So I do listen!

I looked the magnum head swap idea but that was going to cost a lot for me to change over approx $3000NZD once you take shipping, heads, rockers, push rods, head bolts. (Hughes has a kit for it that has all the parts to do it)

So lets start fresh I now have a 770 cfm holley street avenger carb, air gap intake, a set of 360 heads being pocket ported, port matched 2.02 valves fitted, 30 degree valve job, deshroud valves a little, some blending and shaved 40 - 45 thou to bring compression up, adjustable roller rockers, .028 thin head gasket along with a 2500 stall converter and a trans rebuild kit to handle 450hp with a stage 1 shift kit, not that I think I am going to make 450hp.

I see every 360 dyno flog they run a 750cfm carb or one of those big thermoquads. The airgap has got the big 360 ports where the performer has small 318 ports (performer seems to be not much better than the iron 4bbl intake)

The head porter guy says he should be able to get over 200+ cfm out of the heads upto about .450/.500 lift so that will be good.

Taking 40 - 45 thou off the heads should see me at 62/63cc won't know for sure until the heads have been CC'ed this should bring me into the low to mid 9s for comp.

The .028 heads gasket is better than the .039 - .048 felpros this will also help gain some compression.

I also now have a trans kick down cable setup to get rid of the linkages. Have a trans cooler to go in as well.

So once all this is done and don't shoot me down for using a 3.21:1 rear end ratio, gas has gone up here we are at $12.39NZD per gallon! So don't you guys in the USA ever complain about gas prices!

This is going to take me a while to get all this sorted, the trans parts are still on their way from USA and the heads are still at the shop getting worked on. Once the heads are done they will out flow stock X and J heads.

So this should be more inline with what your guys have told me in the past, lots of flow and good comp make good power!

Thanks
Bruce
 
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kkritsilas

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Bruce:

What cam are you going to put in?

THe rest of it sounds fine. There is nothing wrong with a 3.21 rear gear, it is a good comprimise between standing start acceleration, and not turning excessive RPM at cruisng speeds. Your head porter may be somewhat optimistic.
 

Bruceynz

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Cam is unknown might get a better idea when intake and heads off, its got rough idle and seems to come alive about 1800 rpm. Head porter did race car heads, he has squeezed out 5% more out of a head that was unable to flow anymore than it already did. He prefers alloy and only doing cast to help me out, time will tell. He is pretty confidant he can get 200cfm, who knows, stock x heads can flow over 200.

Cam pulls 11 - 12" of vacuum, it jumps between 11-12 at an even rate at the idle speed of the engine, this would suggest it has a cam with large overlap. I checked it at 850RPM
 
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kkritsilas

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Bruce:

LA heads in general are hard pressed to go over 200 CFM; not saying it is impossible, just really hard if the ports are not just hogged out to maximum size. If they are, you can get the CFM number, but it will slow intake velocity at lower rpm. If he gets the heads to flow 200 CFM, and they work well at street RPM, full credit to him.The EngineQuest heads are 230-240 CFM (standard Magnum heads are 210-220 CFM or so) out of the box, and can hit 250-270 CFM ported. There are many reasons that Chrysler Engineering came up with the W series heads for performance applications. The EngineQuest heads have a lot of things changed vs. the LA heads to get to their CFM ratings, and are sort of "improved" Magnum heads.

11"-12" vacuum is a little low for a street driven car. The 11-12" of vacuum indicates a lot of either overlap, intake duration, or lobe centers that are closer together than stock. This may be acceptable to you since you are running higher compression, you will only know after you put the engine back together. If not, try the stock cam if it is still available.
 

jasperjacko

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My 2 cents. If this is a cruiser with good mpg, skip the porting and big cam. If small cam, also skip the rpm intake and just use the performer. Remember, the engine should be built around the cam, and your intended purpose. Small cam with big ports is no good.
 

AJ/FormS

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Here in My Province, we are enjoying a current low gas price of $1.09/liter or 3.97/USg. This is down from about 4.66 last summer. Going with the high number, as I'm sure it will be back; To put that into perspective, I have to work just about exactly 1/4 hour for that US gallon. An hour's wages will buy me 14.6 liters@$1.28/liter.
How does that compare to where you live?
 
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Bruceynz

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I would say just a half an hour down here.

I have decided to change tack and go the other way now, you guys convinced me that was the better way. I sold the nice comp cams I had it was an idle to 4800rpm, got a buyer for my performer manifold and 600 carb I have gone with the stall converter and high flow heads, as for head flow I will have to leave that in his hands to sort out. I have gone dual plane intake rather than open. I have taken on your guys advice 100% and run with it. The only thing I haven't done is changed the rear end ratio.
 

Bruceynz

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I call gas liquid gold when I pay for it, I fill my 2004 Pontaic GTO up (Holden Calais in NZ) and takes $120 and its not dead empty.
 

AJ/FormS

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At $1.28/liter, it costs me about $85.00 to fill the wife's Buick. That is about 4.5 hours wages.That is about 66 liters/18 galUS
Liquid GOLD is right!
I am semi-retired and work about 22/24 hours per week, so that represents about 20% of my weekly income.
My dear wife,who is turning 60 in March, also works about 24 hours per week, and at about the same wage; so that makes it about 10% of our combined weekly income.
 
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Bruceynz

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AJ/Forms - You had a lot of input into me scrapping my last idea, you went through all the math, piston pressures, rear end ratios, percentage of acceleration, ka booms and there you have it etc, so I am on the right track now, more comp, more flow, more carb cfm, high stall converter?
 

AJ/FormS

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Bruce, I need you to refresh my memory,lol
What are your targets, and what are you working with?

Headflow should rule combo.And everything else should be chosen to support the flow.I am A big fan of decent cylinder pressure, and tight quench.

You can put lipstick on a pig, but she's still a pig.You can't make a silk-purse out of a sow's ear.

Slow heads will make a Slow engine, no matter how much cam or compression you throw at it.
Fast heads will make a fast engine, even if you are just barely in the ballpark with cam and compression.
But there is no reason to select more head than you need for the application. You don't need mega power to cruise the hiway, 50 horsepower is more than enough....A daily driver might be happy with 150 to 200hp.... The average guy doesn't know what to do with 300hp.....More than 350 can get you into trouble.... More than 400HP, can get you into a LOT of trouble in a really SHORT time.... After 450 I have no experience, And I'm not at all unhappy about that.

I am a big fan of getting the right pistons to make the right chamber, to help the heads to what they were ported to do. I'm not a fan at all of cutting heads, but I understand that where you are, things seem to be very expensive, and 40/45 is not excessive.
 
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AJ/FormS

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Well here are the basics, correct me where I might be wrong.

This going to be a ROAD car, and a tire fryer. The speed limit is 60mph, and no drag-racing.
>The engine we are working on is a 360, with 2.02-LA heads, and a 340 type cam but with low vacuum, an AirGap. and 770Holley.You are targeting compression in the range of 9.2 to 9.6. And no tight quench.The heads are already at the headporters, and you believe they are gonna come in at about 200cfm.
>The tranny is an A998,(with ratios of 2.74-1.54-1.00), and
>The rear is an 8.25 with 3.21s

Q1 What about fuel mileage?
Q2 Are the pistons flat-tops or dished, and if dished have you cc'd them yet
Q3 Just how far down in the holes are the pistons? This will become very important shortly.
Q4 I assume headers and dual exhaust,right?
Q5 No suregrip yet.
Q6 You think the TC is a 2500
Q7 How heavy is the car
Q8 What altitude are you at

So far this is looking pretty good.Well except for the 3.21s, but I understand about those.
 
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Bruceynz

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Well here are the basics, correct me where I might be wrong. Replies in bold

This is a ROAD car, and a tire fryer. The speed limit is 60mph,100kmph (62mph) and no drag-racing. Maybe just at the traffic lights :) Might take it down to the drags just to get the piece of paper!
Q1
;What about fuel mileage? - Can't have both, small cam and heads was going to kill perfromance
The engine we are working on is a 360, with 2.02-LA heads Yes, and a 340 type cam cam pulls 11 - 12" vac at 850 rpm, bigger than 340 cam I think, when I have eveything apart I will know more.(600 carb has been jetted and tuned by V8 mechanic in my city), an AirGap Yes. and 770Holley Street Avenger not sure that makes any difference.You are targeting compression in the range of 9.2 to 9.6 yes to try and keep on pump gas in NZ. And no tight quench.sucks but need to have zero deck to get any benefit from quench You believe the heads are gonna come in at about 200cfm - I hope so but someone has said your pushing shit up hill with your fingers on that one, will have to leave it to the head porter to see what magic he can do.
Q2
are the pistons flat-tops or dished, and if dished have you cc'd them yet,and - Yet to be CCed, had camera down plug hole looked like flat tops and a fair bit down the bore. Cant't be sure until heads are off, I know a bit unknown.
Q3
Just how far down in the holes are the pistons? China I reckon This will become very important shortly.Agree they are down the hole.
Q4
I assume headers and dual exhaust,right? Still working on this, hope to have a big single due to gas tank offset, running summit headers.
The tranny is an A998,(with ratios of 2.74-1.54-1.00), and you have an 8.25 with 3.21s and I am or going to rebuild a non lock up 904 as stall converter is non lock up. Lock up seems to be more of a hassle than a help, just loose 10% fuel economy on the gold
Q5
no suregrip yet. Correct and would like a LSD, maybe a future upgrade.
Q6
You think the TC is a 2500 Bought one that is 2200 - 2500 rpm stall, with a few variables won't know until its in the car.
Q7
how heavy is the car I dunno approx 3500lbs I thought, never had it on scales
Q8
What altitude are you at Sea level or just above or below in some parts of my city! Scary eh! Christchurch is built on a swamp!


down the hole.jpg


 
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Bruceynz

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I did advance the timing we bit and when it is nice and hot it idles a bit better, but you still get the idea! I thought 11 - 12" of vac gave it away to being something substantial in there.
 

Bruceynz

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So since the thing appears to have a decent cam in it I was going to bring up everything else to match up with the cam, problem solved it would be deturd!
 
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