318 build with dyno session

Stock stroke or 4" stroker?

  • Stock stroke 318

    Votes: 48 88.9%

  • 4" stroker 318/390

    Votes: 9 16.7%
  • Total voters
    54
  • Poll closed .
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Me: I’m happy with my mild 318
Also me: I’m going to follow this thread so I can someday tear it down again and build my 318.
Looking forward to the results!
 
I’m thinking it’s a pretty safe bet that NC EB won’t be attempting to bore a 318 block .130” for this build.
 
Let me start by saying, I am definitely NOT a head porter, but the dilemma I'm pondering now, is that the speedmaster heads as cast, have the throat percentage to big for the 2.02 valve size for my liking, especially on a 322 cube engine. Theres not really a quick and easy way to fix that, so I'm gonna need to decide if I can live with that or come up with a alternative plan.
 
NC Engine Builder said:
Let me start by saying, I am definitely NOT a head porter, but the dilemma I'm pondering now, is that the speedmaster heads as cast, have the throat percentage to big for the 2.02 valve size for my liking, especially on a 322 cube engine. Theres not really a quick and easy way to fix that, so I'm gonna need to decide if I can live with that or come up with a alternative plan.
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Does that mean 2.055's or 360 cast heads?
 
318willrun said:
Does that mean 2.055's or 360 cast heads?
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I'm not sure yet, but definitely no on the 2.05 deal and cast heads dont seem like the answer either, I'm weighing options currently. I kind of want to keep this build simple, something the everyday guy can assemble himself, nothing exotic, no crazy head porting or anything like that.
 
NC Engine Builder said:
I'm not sure yet, but definitely no on the 2.05 deal and cast heads dont seem like the answer either, I'm weighing options currently. I kind of want to keep this build simple, something the everyday guy can assemble himself, nothing exotic, no crazy head porting or anything like that.
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Most everyday guy is gonna probably run it with stock size valves ported or not.
 
NC Engine Builder said:
I'm not sure yet, but definitely no on the 2.05 deal and cast heads dont seem like the answer either, I'm weighing options currently. I kind of want to keep this build simple, something the everyday guy can assemble himself, nothing exotic, no crazy head porting or anything like that.
Click to expand...
I had high hopes of building a simple 318 with my 80's roller block and some Speedmaster heads. I have a steel 273 crank and the stock 318 cast crank. Or should I just put in a stroker crank and call it a day. :BangHead: :BangHead: :rofl:
 
toolmanmike said:
I had high hopes of building a simple 318 with my 80's roller block and some Speedmaster heads. I have a steel 273 crank and the stock 318 cast crank. Or should I just put in a stroker crank and call it a day. :BangHead: :BangHead: :rofl:
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Depends what the goal is, to me the reason to build a 350 - 450+ hp 318 is cause you want rpm, If your gonna stroke it, a 390 ish engine obviously can be bad ***, but I'd dig up a 360 block for a 408 why give up 18 cid if stroking $$$ for cid.
 
PRH said:
I’m sure the majority of those heads are run in basically “ootb” form.
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I did that just to see on a stock 360. SM heads only went about 2 tenths quicker than stock 360 heads. And probably half a tenth was in weight. Again, my cam wasn't able to take advantage of the heads. I even used the stock stamped rocker arms.
 
318willrun said:
I did that just to see on a stock 360. SM heads only went about 2 tenths quicker than stock 360 heads. And probably half a tenth was in weight. Again, my cam wasn't able to take advantage of the heads. I even used the stock stamped rocker arms.
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What was the mph difference?
 
273 said:
Depends what the goal is, to me the reason to build a 350 - 450+ hp 318 is cause you want rpm, If your gonna stroke it, a 390 ish engine obviously can be bad ***, but I'd dig up a 360 block for a 408 why give up 18 cid if stroking $$$ for cid.
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I already have a roller block collecting dust. Either would be easy to build and get 400 horse. It's a underdog thing. Like putting it together with .030 flat tops and calling it a day. A decent fairly mild cam and 400 horse at the crank. Nothing wrong with that. No need for maximum horsepower.
 
Nick dyno'd a 390 through manifolds and got 406 hp and 440 lb/ft. That's more than enough for a street cruiser.
 
NC Engine Builder said:
We just made the same torque with much better power with a stock stroke 340 a few weeks ago
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Those 340's are magical. Bore to stroke combo? They work best with big valve heads. Just think about what happened in 72 with the small valve heads, cam, and the like.
 
NC Engine Builder said:
I'm not sure yet, but definitely no on the 2.05 deal and cast heads dont seem like the answer either, I'm weighing options currently. I kind of want to keep this build simple, something the everyday guy can assemble himself, nothing exotic, no crazy head porting or anything like that.
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NC Engine Builder said:
I'm probably just gonna pretend like I didn't measure the throat and carry on!
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Exactly! Best move possible. 99% of the people out there are going to use the head in it’s OOTB condition (hopefully after inspection and cleaning) and just bolt them in and go calling it good.

To me, this is an honest comparing against whatever else was used before hand.

It’s to much B.S. to “Fix” the head to fit the build. Nearly no one else will do it.
 
To add;
99% of people dont know how to measure, or will ever need to measure throat percentage of valve size or what that even means and how it affects the engine. Forget it, bolt em on and move forward.
 
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