318 with 360-587 1.88 heads

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68GTconvert

68GTconvert

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Well money is getting really tight and I have a fresh 30 over 318 with 360-587 1.88 heads. It has a smallish 450 lift RV cam in it. The heads are fresh with a port match job for the RPM intake. I think they may be milled a bit. I am not sure about the compression. I know this is not alot of info but I am thinking a quick cheap running 318 with a bit of power. I think the pistons are speed pro. I have all the parts to make a complete motor and I know this 318 is a good runner.

What do you think HP wise I could get out of it with a small cam upgrade maybe a 484 cam or what cam would you recommend? and a Eddy RPM intake and PRW rockers with Dougs headers and I have a 750 speed demon carb.

I am thinking about selling my 402 stroker with RHS heads to fund Mortage and bills and build this 318 for a temp motor. I know I am going to regret it but I may have to do what I have to do.

Advise? Sell the wife? Sell The dog? Sell my Dirt bike? I have to keep the kid.
 

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Stick a mild cam in there to keep cylinder pressure up. Go with thinnest head gaskets you can find.
 
I feel for ya' as i'm in the same boat right now. Those pistons in the pics look like a stock replacement type piston, probably a 1.74 CH. Depending on how much the heads have been milled your comp ratio will be in the 8 to 8.5 range. That's why i choose a reasonable intake duration at .050. Should still be a pretty strong runner with the other bolt on's your using.

I looked up Speed-Pro pistons and they are 1.76 CH. but i'll still stay with the same comp. ratio guess.
 
OldmanRick said:
I feel for ya' as i'm in the same boat right now. Those pistons in the pics look like a stock replacement type piston, probably a 1.74 CH. Depending on how much the heads have been milled your comp ratio will be in the 8 to 8.5 range. That's why i choose a reasonable intake duration at .050. Should still be a pretty strong runner with the other bolt on's your using.

I looked up Speed-Pro pistons and they are 1.76 CH. but i'll still stay with the same comp. ratio guess.
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Damn. I was hoping for a bit more compression. That kind of changes the ballgame. Should I just pick up some better pistons? Or does that make it cost ineffective? Feel like it will be a dog at 8to1.
 
68GTconvert said:
Damn. I was hoping for a bit more compression. That kind of changes the ballgame. Should I just pick up some better pistons? Or does that make it cost ineffective? Feel like it will be a dog at 8to1.
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I'll run some numbers and get back to you. Higher comp. height pistons aren't real cheap. I'll try and see what will be the most cost effective for a budget build, not knowing the exact chamber cc on the heads.
 
Your last link didn't work for me. But here's what i got with the other info.

Using 72cc stock heads with a .028 gasket, the original Sealed Power pistons and .080 below deck it comes out at 7.7 to 1.

With the KB's and the same calc. it's 8.82 to 1.

Now with a 68cc it's 9.20 to 1.

And 65cc it's 9.51 to 1.

There's more calculations, but the head chamber cc will really determine where it's at.
 
Just to add, if i use the original 7.7 to 1 numbers with a 65 cc chamber it still only comes out to 8.2 to 1.

With all this confusing mess:D if you want the comp. up and the ability to use a bigger cam, the KB pistons are probably the best way to go.
 
I'm doing a similar build. I've got 360 heads on a 318 block, 340 cam, 600 cfm carb, torker 340 and headers. going to put a od 4 speed behind it with 3.23s out back. Compression will suck but I am thinking I will just get a supercharger down the road to take advantage of the low compression.

Nice 22r valve cover! I've got a 22re myself, too darn slow though.
 
Since the heads are off of it, rotate that sucker over to TDC and measure how far down the pistons are in the holes. I'd check one on each side just to see if it's close, 318's aren't known for always being square.

You can have the heads cc'd, or do it yourself, it's actually not all that hard. All you need is the clear plastic "cd" at the bottom of a blank cd package, or a flat piece of plastic and a graduated beaker or syringe. I use a heavy weight oil, easier to deal with and less bubbles than water or thinner liquids. Just meaure out a given amount, fill the chamber and see what youve got left over. You can also use clay to pack the chamber, and then throw that in a graduated beaker filled with water to see the displacement. Usually those methods are accurate to a cc or two, better than the 65-72 cc range the heads usually run in.

That will let you really calculate the compression and see where you're at, it'll make a big difference picking a cam.

I would think you'd be better off finding a set of magnum heads, they're closed chamber and usually in the 60-62cc range. Much better on a 318 than LA 360 heads because they keep the compression up, and they even have bigger valves. They're getting a lot easier to find in the wrecking yards and are usually pretty cheap. Just have them magnafluxed to check for cracks before you run them.
 
484,out of the question.Personal grinds,by experience.3.55 gear,or under.31915 Crower Baja Beast.in a simalar 360,rev past 6000.Doesn't fall of 4.10s up,Crower 31916.1.88/1.60 valves,bowl work.Simply hang on.Those are personal references,anything comprable will work.
 
72bluNblu said:
Since the heads are off of it, rotate that sucker over to TDC and measure how far down the pistons are in the holes.

Could I use my 63cc RHS heads?
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Measure how far below deck the pistons are. If they are at .080 like i ran the numbers, even with the 63cc would still only be 8.4 to 1.
 
Are you 1.92 stock,or 2.02? 1.92,,no problem.Airflow,trumps compression.Pay ,way attention to overlap.
 
68GTconvert said:
202. stupid ? Do I measure how far in the hole by inches.
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Funny as it sounds, another member here laid two pennies on the piston and came right to the deck. I measured two myself and came up with .080. Not exact i'm sure, but pretty darn close...lol.
 
Abodybomber said:
Are you 1.92 stock,or 2.02? 1.92,,no problem.Airflow,trumps compression.Pay ,way attention to overlap.
Click to expand...

They are 202 RHS heads from IMM. I have never built my own motor just bolted on heads and accessories. So I am limited on what I can do.

Whats involved in a small solid cam?
 
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