Aluminum heads

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slowdown

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So I pushed out a head gasket and am looking into some aluminum heads to replace the Rhys/Indy lax heads I have on it now. I’m going to put cometic mls head gaskets back on and am looking at the speed masters on jegs sight that say in stock. I’m looking at these ones PCE281.2148 because it says 68cc and my compression is a little higher than it should be with a supercharger. I have a 4” scat rotating assembly with the -23 dish pistons and a xe284 comp cam in it. I think it’s like 9.5 compression or maybe more a little more. I was hoping the 68cc would bring the compression down a little and with a better head gasket not push it out. I just had the old blue felpro in it but they lasted a few summers, I guess I may have been lucky. It’s not a race car I just take it on cruises and smoke the tires every now no again so I’m thinking these will be ok?.. What do you guys think.
 
I think that no matter what compression an engine has, adding pressure is almost always OK. Know your cylinder pressure! The draw back comes from two things. To much timing and/or not enough octane. Readjust your tune on the timing and it’s curve as well as the octane being used.
 
rumblefish360 said:
I think that no matter what compression an engine has, adding pressure is almost always OK. Know your cylinder pressure! The draw back comes from two things. To much timing and/or not enough octane. Readjust your tune on the timing and it’s curve as well as the octane being used.
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Thanks! I did have it tuned and dyno’d a summer or two ago I’m not even sure how long it’s been time flys. I have a coworker who runs a blower car offer to lock out my timing but I’ve heard good and bad so I just left it. I was just thinking while I had the heads off anyway it would be a good time to switch to aluminum heads. And I just the 68cc would be a better option than 62cc. But I’m not a engine builder by any means. I do use a water methanol snow kit and I use the highest octane at the pump. But I may have gotten bad gas, I did have my foot in it way longer than usual when it let lose. Thank you for your quick reply.
 
slowdown said:
So I pushed out a head gasket and am looking into some aluminum heads to replace the Rhys/Indy lax heads I have on it now. I’m going to put cometic mls head gaskets back on and am looking at the speed masters on jegs sight that say in stock. I’m looking at these ones PCE281.2148 because it says 68cc and my compression is a little higher than it should be with a supercharger. I have a 4” scat rotating assembly with the -23 dish pistons and a xe284 comp cam in it. I think it’s like 9.5 compression or maybe more a little more. I was hoping the 68cc would bring the compression down a little and with a better head gasket not push it out. I just had the old blue felpro in it but they lasted a few summers, I guess I may have been lucky. It’s not a race car I just take it on cruises and smoke the tires every now no again so I’m thinking these will be ok?.. What do you guys think.
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Since you are planning to run Cometic gaskets anyway, why not just order thicker gaskets to lower the compression? Cheaper that way if your combo usually runs well as it is.
You did not give all your build specs so I am assuming you are running the .040” or less compressed thickness right now.
 
Bobzilla said:
Since you are planning to run Cometic gaskets anyway, why not just order thicker gaskets to lower the compression? Cheaper that way if your combo usually runs well as it is.
You did not give all your build specs so I am assuming you are running the .040” or less compressed thickness right now.
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Yes sir you are correct it is .040. I had read a thicker head gasket didn’t lower compression as much as I would think. I’m not 100 percent as I only read it. And I thought a head gasket being thicker may make it easier to push out? Like I said I’m not a engine builder, I did build mine but may have gotten lucky with my results. The combination I think performs well I had just recently pushed the head gasket out and it made me think about switching to a aluminum head while I was that far. I was just kinda wondering about the 68cc helping me from the 62cc. I have been running this engine for several years but really only put maybe 100 miles a summer as I don’t have much time to take it out and actually drive it. I can change to a better head gasket and and check the tune again like RumbleFish said and maybe a higher cc head may help? I read aluminum heads can help with compression as well. That’s also the other reason I was thinking about swapping the iron heads to aluminum. Thank you.
 
slowdown said:
Yes sir you are correct it is .040. I had read a thicker head gasket didn’t lower compression as much as I would think. I’m not 100 percent as I only read it. And I thought a head gasket being thicker may make it easier to push out? Like I said I’m not a engine builder, I did build mine but may have gotten lucky with my results. The combination I think performs well I had just recently pushed the head gasket out and it made me think about switching to a aluminum head while I was that far. I was just kinda wondering about the 68cc helping me from the 62cc. I have been running this engine for several years but really only put maybe 100 miles a summer as I don’t have much time to take it out and actually drive it. I can change to a better head gasket and and check the tune again like RumbleFish said and maybe a higher cc head may help? I read aluminum heads can help with compression as well. That’s also the other reason I was thinking about swapping the iron heads to aluminum. Thank you.
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Yep, you just go on and switch to aluminum heads and sell those old crappy Indy heads to me. Trickflow 190's is what you want.
 
What you really want to do is hold your horses for about 6 weeks and look on the Speedmaster website on Black Friday...
The last couple years people are getting fully loaded sets sent to their door for 700 bucks... For your intended use this is probably the best bang for your buck...
They work great for me on my stroker for the last 2 years...
 
j par said:
What you really want to do is hold your horses for about 6 weeks and look on the Speedmaster website on Black Friday...
The last couple years people are getting fully loaded sets sent to their door for 700 bucks... For your intended use this is probably the best bang for your buck...
They work great for me on my stroker for the last 2 years...
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The question is will there even BE a black Friday sale? Will they have anything in stock TO sell?
 
33IMP said:
The question is will there even BE a black Friday sale? Will they have anything in stock TO sell?
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Well that was the question last year at this time and they did...
You can always check their website or give them a call...
It would be my first choice..
 
I think the Jegs web site suggest that they are not in stock and that they ship from the manufacture and that speedmaster is probably out of stock too.
 
I have bought a lot of stuff from there website......probably close to 10 sets of heads....never had a problem...

If you order from summit or jegs.....It is usually drop shipped from Speedmasters warehouse.
 
Bodyperson said:
Ya I was just headed there. Limited though. Man I dislike that site. I would never buy through that site. Have other people?
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Prior to the dempanic, I bought a really great deal on BBC stuff from speedmaster from their black friday sale.
Delivery took almost four months and numerous pissed-off phone calls. They claimed they were out of stock due to unforseen demand, and it may be true. I think they just didn't want to sell at that price, and we're hoping I would cancel the order.
 
Bodyperson said:
Ya I was just headed there. Limited though. Man I dislike that site. I would never buy through that site. Have other people?
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Not a friendly website for sure. Cheap parts, cheap website.
 
I would need to know more.... but fwiw
1008 felpro-.039 thick
8553 felpro-.046-.048 thick
519sd felpro-.054 thick

"Regular blue felpro" the 8553?
Try the 519sd and keep the good heads you have. If you were close...I could dial all the chambers in=enlarge them. I think you can fix this without changing something as important as the heads
 
Changing to an aluminum head would be a good move but there are quite a few options and more opinions. Let's leave the shipping problems or possibilities of off the table. I also have ran the speedmaster heads with good success(normally aspirated) and you may look at the 190 CNC version I believe it also has a slightly larger combustion chamber that may be a good fit for you.
 
K.O. SWINGER said:
Changing to an aluminum head would be a good move but there are quite a few options and more opinions. Let's leave the shipping problems or possibilities of off the table. I also have ran the speedmaster heads with good success(normally aspirated) and you may look at the 190 CNC version I believe it also has a slightly larger combustion chamber that may be a good fit for you.
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I with the idea of the 190cnc.
I wouldn't swap rhs for stock seedblasters
 
Does Felpro still make an o-ringed head gasket? I used them on a blown big block chevy in the early 80's. Later, I o-ringed the block too, same head gasket.
 
Bodyperson said:
Ya I was just headed there. Limited though. Man I dislike that site. I would never buy through that site. Have other people?
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They remove customer reviews if they're negative. I reviewed heads that were advertised at 179cc intake port... they measured an actual 150cc!!!
They removed my review for stating a fact. That says enough right there.

Stay away.
 
If you look at the heads they offer, that PN has the chamber as cast, just like the unported heads. They have a different PN with cnc Chambers that are possibly 68cc. But I measured my set of PCE281.2148 and got 65cc on the nose. Intake Ports came in at 188cc.
 
Charlies heads are out in the Pacific, they won't be here for Black Friday so order your Trick Flows :usflag:today
 
TurboGLH said:
If you look at the heads they offer, that PN has the chamber as cast, just like the unported heads. They have a different PN with cnc Chambers that are possibly 68cc. But I measured my set of PCE281.2148 and got 65cc on the nose. Intake Ports came in at 188cc.
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Not as advertised. :elmer:
 
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