The aftermarket aluminum heads w/2.02’s will fit the 318’s standard bore. What’s the problem?
Speedmaster heads for SBM
- Thread starter moparmat2000
- Start date
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Dan the man
Well-Known Member
Sure they will fit. But the 2.02" intake valve's and the bigger ports will hurt low end torque. It's been proven that smaller valve's along with good port work will give excellent results. A 318 will have to be spun at a higher rpm's in order to get the full benefit of the larger valve's and ports. I wish that a cylinder head company would offer a cylinder head especially for the 273 / 318, one that has 155 - 165 cc intake runners and 1.880" intake valve's and 1.600" exhaust valve's. Edelbrock has a cylinder head just for the small bore small block Chevy. A cylinder head that has good port velocity. The AFR165 heads for the sbf has 165cc intake runners and they have good port velocity. I believe that if they were to offer a cylinder like that that it would sell well as I've read on here countless times about guy's looking for good heads for their sbm. Sorry about high jacking this thread but I wanted to say what I thought and I'm probably wrong and some may disagree with me and I'm fine with that. Sometimes you have to create a demand.
IMO, you’re over thinking it. But that’s OK.
I’d like to see the tests of a head to big for a 318 and a 2.02 valve. Also, as you said you have to spin it higher to get the full benefit of the head. That would apply to every head and cam set up on every engine and it applies to 99.99% of everyone with a car. The point .01 percent it doesn’t apply to are those that drag race and I’ll make the claim many racers do not take full advantage of the heads port ether.
I’d like to see the tests of a head to big for a 318 and a 2.02 valve. Also, as you said you have to spin it higher to get the full benefit of the head. That would apply to every head and cam set up on every engine and it applies to 99.99% of everyone with a car. The point .01 percent it doesn’t apply to are those that drag race and I’ll make the claim many racers do not take full advantage of the heads port ether.
Rat Bastid
Dunamis Metron
100% untrue horseshit. You are repeating why you’ve heard, not what you know.
You do know about rules of thumb don’t you? There are many of them and they are used for quick and dirty calculations that don’t require a bunch of math.
Let me give you one.
For in-line wedge heads, you want the intake valve to be 50-52% of bore diameter. That means with a 3.910 bore, you SHOULD be using (at a minimum) a 1.955 and a maximum of 2.0332 valve diameter.
You can do the math and figure out that most factory junk doesn’t follow that rule. and I’ve seen guys argue that same worn out velocity bullshit that always comes up. and it’s WRONG.
The reason the OEM’s don’t follow that rule isn’t because a smaller valve/port has more velocity (if you have ever ported heads and intakes and worked with a flow bench you could test this for yourself) but like everything else, the valve size decision is based on money. Scrilla. Cabbage. Whatever you want to call it. The decision is mostly financially driven.
Just like why the small block Chrysler has a what? 1.68ish valve spring installed height. Because a shorter spring costs less MONEY. Which means you can what? You use a shorter valve. And a shorter valve costs LESS MONEY.
I hate to break it to you but most of the decisions on the architecture and geometry of these engines is financially and NOT performance driven.
In high school I build a 318 for a guy from another school. It went together with a Strip Dominator, Hooker 5204 headers, a DC 284/.484 cam and 360 heads. Yes, I gave up compression to get port and valve size.
The guy made far more than the cost of the engines going out and taking money from big block guys and dullards.
Could we have used 2.02 heads? Yes? Why didn’t we? COST. We were in high school. We didn’t want to blow our wad on these things. We had girlfriends (expensive), we had beer to buy and other things to do. So we saved the money.
So the small valve, small port LIE needs to go away.
Again, if you had a flow bench you could test all this. You’d learn right quick that porting heads and intakes is nothing more than velocity management. You can have too much velocity and I see it quite often.
Dan the man
Well-Known Member
What I do know is that I have friends who's cars that had cylinder heads from a 360 and 2.02 intake valve's ran better when they went with 1.880" intake valve's. And you don't neccesarily have to spin a engine higher rpm's with a cam and cylinder head change unless the cam is pretty radical. Most guys I know their cars run great and don't spin them over 5500 -6000 rpm's
Rat Bastid
Dunamis Metron
I’ve heard that bullshit too. Never had it happen to me. You can keep pretending you know what you are talking about, but you don’t.
B3422w5
Well-Known Member
Dan, are you the guy down that way with the white Demon?
I e never gone slower with a 2.02 and even more so against a 1.88.
I PM’d Dan and wrote a few messages to him. I figured a few videos from Richard Hold we would clear a few things up as well as create more questions. I specifically sent him to the Fire section where Richard runs through displacement sizes of 320, 331, (IIRC) 347 & (IIRC) 393 with near stock cams to small street cams to pretty healthy cams that can be a real bruiser on the street for sure
During all of the testing, he runs through many heads from many companies in various size cc runners and such. It’s very informative and can be eye opening if not overwhelming to a new guy, so slow digestion of this should be done. Just a few videos at a time to view and think about.
It’s funny because nothing is in stone. The variations are darn nearly infinite. Certainly head spinning.
When I watch these videos, I try and play a little guessing game in my head as quick as I can before he shows the results of the run. While I have to state I’m not the most accurate by far, I’m not really surprised (being in the ball park of the combo) but often certainly do pick something up.
I told Dan to watch a few at a time and think about it.
I suggest the same for everyone else no matter how seasoned you think or actual are.
The take away from everything Richard does on the heads should help anyone in their next head choice. For me, even before I seen Richard’s channel or the vine masters is, well, Freiburger says exactly what I say, “Get the best cylinder head you can afford!”
For me, it was the TF-190’s on my wife’s 11-1 360cid with a hydraulic roller cam. I’ll end this with lift the valve as high and as much as the head flows good and maybe a tad more since it’ll see that value twice. It’s not always needed but you’re taking the max advantage you can on the head this way and why not?
mygasser
Well-Known Member
i'm slow to the party here but i agree you're wrong.
junkyardhero
Well-Known Member
are you kidding? dan doesn't even have a car!
mygasser
Well-Known Member
far too fussy from what he's said so far. there's not many champagne cars on beer budget money about these days though so......
Way too many people think just throwing a 2.02 valve in a 1.88 head is going to make more horsepower. If anything they ruined the head if they didn’t size the throat properly.
Rat Bastid
Dunamis Metron
I wasn’t going to go there because I couldn’t say it as nice as you did and I didn’t want to piss anyone else off this week.
Just ridiculous.
Facts spoken there! ^^^^^^^
I was pretty nice there wasn’t I. And the spelling was pretty good for having two cats laying on me and my bifocals 8 feet away. Lol
You guys must not look very hard. Blocks have been available for years. Back on small block stuff. Sorry.
More facts!!! ^^^^^^
So, in this situation, Dan is right?
How do you figure
He said they swapped out 1.88 heads for 2.02 heads and it ran better.
Maybe he just didn’t know how to prep the 2.02 heads properly. That’s my guess. He does lots of reading and assuming kinda like you are.
I was assuming but that could have been the condition he was speaking of. I should have said "could" be right
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B3422w5
Well-Known Member
Everything is relative.
A head guy I know has a 1.94 intake valve(327) 10 to 1 Nova at 3200-3300 pounds running 9.80’s wheels up with the factory iron heads on it in S/S.
He swears on small hole, torque and velocity in everything he does.
And to say he is well respected is an understatement.
A head guy I know has a 1.94 intake valve(327) 10 to 1 Nova at 3200-3300 pounds running 9.80’s wheels up with the factory iron heads on it in S/S.
He swears on small hole, torque and velocity in everything he does.
And to say he is well respected is an understatement.
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