340 valves in 318 heads???

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'teen machine

'teen machine

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Hello, I have a '75 318 and I like almost everybody else am looking to get a bit more snort out of it. Would 2.02 and 1.60 (340) valves fit in my 318 heads? I realize I'd have to grind the seats, but would i have to change the seats or are there any clearance issues to worry about?
Thanks very much!
:burnout:
 
You can go with larger valves but I would use the 188s on the intake side
 
Yes it can be done, but unless your 318 is pushing a lot of horsepower then I wouldnt do it (because it will make the 318 even worse). If your trying to get the 318 to have some power, do a cam change and bump up the compression. That will wake that 318 up.
 
dodgetkboy78 said:
What are you trying to accomplish with your 318 heads?
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Well I have a BURNT exhaust valve and I wanted to up the performance a bit without tearing the engine down.
Seeing as it's a stock cammed 318 2" intake valves might be a bit much. I guess I'll just go with headers, mild porting, and intake and carb.
 
'teen machine said:
Well I have a BURNT exhaust valve and I wanted to up the performance a bit without tearing the engine down.
Seeing as it's a stock cammed 318 2" intake valves might be a bit much. I guess I'll just go with headers, mild porting, and intake and carb.
Click to expand...

good plan
 
No no!!!

SINCE you have a burned EX valve, go ahead and put the larger 1.60 EX valves in your heads, leave the intakes stock. It will make a bit of a difference. :)
 
Or use the heads you have that are just fine with a vlave job with 1.60 EX valves because you have them and that is easy.
 
After all the head work. Seats, Guides, Valves, Springs, and Probably shims Blending the bowls . Add up what you'll have into them in $$. You'll still have small port 318 2bbl heads. For a little more cash you can buy a new set of 360 or aftermarket Alluminum heads. Then you'll see a power increase . Just more bang for the buck. Eddy heads are a real reasonable buy right now.
 
With some porting 'mainly removing the roof kink' the 318 small valve exh will flow with 340/360 stock ex ports.

The ported 318 intake will flow what a stock 360 1.88 valve head does but with the small valve.

stock flow is like 165int/120ex cfm peak, but with simple porting [318 heads are easy] you can have the flow of a 1.88/1.60 j head=200int/145ex cfm

I recommend you keep the stock valve sizing unless you need new valves anyways, in that case maybe think about the future holds for this engine or plans for a bigger engine.

maybe just valve job/hardend seat these heads and call it good.
 
I remember someting about not going any larger than a 1.94" intake on the 318 due to the cyl wall shrouding the valve. I have put 1.88/1.60 valves into the the 318 heads with a 340 repo cam and a single plane holley small runner intake 600 cfm eddy carb. runs really good........
 
dodgetkboy78 said:
No no!!!

SINCE you have a burned EX valve, go ahead and put the larger 1.60 EX valves in your heads, leave the intakes stock. It will make a bit of a difference. :)
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dodgetkboy78 said:
Or use the heads you have that are just fine with a vlave job with 1.60 EX valves because you have them and that is easy.
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dodgetkboy78 said:
On a mild 318? There's nothing wrong with small port heads on a mild 318.
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Yes yes yes yes! To all the above!



David Flowers said:
I remember someting about not going any larger than a 1.94" intake on the 318 due to the cyl wall shrouding the valve. I have put 1.88/1.60 valves into the the 318 heads with a 340 repo cam and a single plane holley small runner intake 600 cfm eddy carb. runs really good........
Click to expand...

The 1.94 is a Magnum valve and not needed in a "LA" head at this stage of the game. While valve shrouding can be an issue, it is an issue of little concern at this stage of the game and even if he pumps up the volume a good bit. IMO, if your not racing the vehicle, no worries about it.

I hate to point to a crap engine and say, they don't seem to worry about it. While there making a good bit of HP more than we are, but, the Chevy engine has alot of shrouding and there current LS engines are making wacked power.

OH, nice set up on your teen though. I know that is a well like set up. What Holley? Streey Dominator?
 
I just bought a set of 2.02/1.60 stainless valves for my 318 heads. I will have the heads ported obviously... A valve unshroud is necessary?
 
Im not sure on the exact holley intake, but it has small narrow ports like the 318 heads and will wake up a 318 in the 5000 to 6500 rpm range. now if you tried a m1 intake it would kill the power throughout the rpm band. ill try and find out what intake the holley is, i dont think its a dominator though and right now its on my buddies 360 so is only a mile away to get the #'s off of.

bottom line is that the 1.88/1.60 valves work out great on a 318 and i doubt any one will argue that, and its an easy job to do. If one wants to start an argument about what is best, thats another story.
 
David Flowers said:
Why is it when i say 1.94" valve you automatically think chevy.
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Why is it dumb people reply indirectly to me (Since I'm the only one who mentions anything after that post) and starts in with me (Like A dumb ***) thinking they know WTF there talking about.

YES, that would be you Mr. Flowers. Go back and read my post and you'll not only notice that ethier you read wrong, inserted words that were not there or just AS/U/ME'd that the word Chevy was in there.

Also notice I never made a mention to a Chevy vale in being cut down but the word "MAGNUM" as in MoPar MAGNUM is used.

I mentioned Chevy in there description of not being worried about valve shrouding in there engines.

Thanks for playing.....
 
boy rumblefish360 you are a sensitive dude, yes i did read that wrong but if you had as may beers as i did you would have too LOL. And you call me dumb? you dont even know me, what I do, or have done. But like i said bottom line is that no one will argue that 1.88/1.60 is a bad thing to do on the 318 heads he has now. Arent magnum heads running a 8mm valve stem 1.92" valve? I have been out of the car scene for about 10 years now and have some catching up to do but I am far from dumb. And i fixed my previous post for you so you can now remove that stick from your butt.
 
OK....so can I put late '70s 360 exhaust valves in my 318 heads without having to put different keepers or retainers in? Also would I have to grind the seats much to put .1" bigger valves in?
 
it's a circle, so you'd only cut half of the desired finish size, just like cylinder.

Yes, go ahead and have them stick the 1.60 exhaust valves in there.
 
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