compression ratio on pump gas

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How do guys think a XE262 cam would do with this same combo LA/magnum any good??? Maybe more octane friendly!!!
 
I am at sea level and have no problems at all with a Comp Cams XE268H in there. The smaller the cam the more chance you are going to run into problems. The bigger cam, (although there is not that much difference between a 262 and 268 ), helps in this type of build.

Jack
 
AdamR said:
Luckily your here to save the day !
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And luckily you're here to be a total smartass and contribute absolutely zero. Really, how was that helpful? That's all I'm trying to do is be helpful. Not trying to save anything. Maybe after this, I'll just save me a place on the couch and screw this place. Butthole.
 
People need to start thinking about Dynamic compression--Static is only a small part of the equation. J.Rob
 
StrokerScamp said:
And luckily you're here to be a total smartass and contribute absolutely zero. Really, how was that helpful? That's all I'm trying to do is be helpful. Not trying to save anything. Maybe after this, I'll just save me a place on the couch and screw this place. Butthole.
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It was no less helpful then your remark were you pretty much said no one on the site knows what they are talking about but you.
 
AdamR said:
It was no less helpful then your remark were you pretty much said no one on the site knows what they are talking about but you.
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No, actually there is more than one with the same train of thought on this thread. I'm glad that I'm keeping you entertained though. Since you're so obsessed with me, maybe your next tat could be of me.
 
As Jack said I too am running 10.58:1 with zero decked KB107's in a 360 with magnum heads and an XE268H cam. The cranking pressure in my engine is 195 to 205 psi. I have almost 50k miles on the engine running 89 octane with no issues. I have tried 87 but high loads at low rpm do cause some detonation so I stick to 89.

The efficient port and chamber design of the magnum heads do not require as much timing. I have found I get the best performance with 33 degrees of total timing. The XE268H cam likes a lot of initial timing and I am running 17. I have springs in the distributor that have the timing all in at 1500 rpm.

I also run vacuum advance and have it adjusted to add 17 degrees at 14" Hg which happens at cruise in the 40 mph range.

All in all I think my 360 is dialed in pretty well for a street car, I get 16.5-18 mpg around town and 21-22 mpg at 70 mph on the hiway. I have an A833OD with 3.55 gears in a 68 Barracuda.
 
RAMM said:
People need to start thinking about Dynamic compression--Static is only a small part of the equation. J.Rob
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This was the gist of my PM to him last night. There's more than one way to skin this cat so it doesnt surprise me whenever this question gets asked. We all have our opinions on "what's best". The issue comes when there is indecisiveness because of all the ideas... not the ideas themselves.

My solution was a quench dished ICON piston, tight quench, and a bigger cam all put together with the eye on dynmic ratio. But been my approach for years now...lol.
 
I have been wondering where you have been DGC.
 
I have been wondering where you have been DGC. I could not remember your exact combo.
Glad you. Chimed in.
 
Side note is id like to know which production mag head dave is using.

But all in all when it comes to sb production mopar heads, they all have small port volumes and lots of air speed....and the carb still mixes it.

Id like to see the fps measured between J's, 318's and mag heads, just for fun.
 
dgc333 said:
As Jack said I too am running 10.58:1 with zero decked KB107's in a 360 with magnum heads and an XE268H cam. The cranking pressure in my engine is 195 to 205 psi. I have almost 50k miles on the engine running 89 octane with no issues. I have tried 87 but high loads at low rpm do cause some detonation so I stick to 89.

The efficient port and chamber design of the magnum heads do not require as much timing. I have found I get the best performance with 33 degrees of total timing. The XE268H cam likes a lot of initial timing and I am running 17. I have springs in the distributor that have the timing all in at 1500 rpm.

I also run vacuum advance and have it adjusted to add 17 degrees at 14" Hg which happens at cruise in the 40 mph range.

All in all I think my 360 is dialed in pretty well for a street car, I get 16.5-18 mpg around town and 21-22 mpg at 70 mph on the hiway. I have an A833OD with 3.55 gears in a 68 Barracuda.
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Good to see you again Dave, glad you chimed in.

Although our engines are very close in design, I have found mine likes 16 degrees initial and 34 total. All in at 2500 rpm. I run a MSD dizzy with no vac and 6AL.

I wonder if the difference is the heads I have are 2.02 intakes and have had a lot of porting done to them.

Jack
 
Scamper: Talk to an engine builder in your area. He/She can better explain what you'll need to run pump gas. Sometimes this board over explains things.
 
Hey Jack thanks for the info. I also am at sea level and i can still take the XE262 out if it will help,But where dose that leave the valve guide to retainer at or do i need machining done to the head. With the XE262 and 1.6 rockers lift is already at just over 500". I was told to keep it close to that to be safe. Can the stock Magnum head take XE268 with no machining. What do you think????
 
1wild&crazyguy said:
:happy1:
Pretty much
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Thats why I posted mine will be around 8.7-8.9 with magnum heads. I think I talked to dgc333 about his dynamic and I think it was 8.6-8.7. But with everything I have read all over the internet says 8.8-8.9 is 93, but idk. Im just going off what my engine guy aka Brian said! And he seems to be making stuff work correctly, so I believe him, but if it doesnt work, then I will mix gas or just lower timing. Not that big of a problem for me, but for others it might be!
 
I would like to thank everyone for their advice! I have decided to play it safe and go with a forged stroker kit and 9.7 comp with the r/t heads. The engine builder feels I can run on pump gas with no problems with this combination and we will be using the xe268h cam since I have aircare to worry about in my city.only bad part of the deal is 1 month before I will be able to put it in my car.
 
Now that i know XE262 is coming out. Make way for the XE268......THANKS Jack!!!
 
built a .060" 360 awhile back, ran the KB190 quench dome pistons with 915 heads, compression was around 10.3, cam was the XE284H, Alt was 3700ft, ran great on premuim, I now have a 406 sbc with 10.4x compression & iron eagles, Alt. is 1600ft., small cam & it runs great on 91 octane.
 
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