360cu Engine Upgrades
- Thread starter Trivium91
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yeah $650, i believe he is going to pick the the springs as im just going to get the cam from him. I've also heard of beehive springs, new technology?>
Ah turns out my heads have already been machined...dont know all the details but something with the valve guides and the intakes cannot be ported to 2.02. So now im stuck using stock heads since i decided not to spring for aluminum heads on this build. I talked to edelbrock and they said their 7177 Cam will work fine with stock heads, they even have a single spring designed to work with their cam which is actually higher lift than the XE274. That being said their cam requires adjustable rockers, can i use the stock shaft and just get the rollers themselves? or is it not strong enough?
M_Body_Coupe
Well-Known Member
Couple of comments here:
So I'm not sure if you are oversimplifying this here, or whether the machinist himself has not given you the info. But, if it the machinist is NOT explaining precisely the reasons for not being able to go to 2.02" diameter intake, my only recommendation would be: FIND A NEW MACHINIST!
Here is the thing, originially (applicable to older small blocks) the valve stem size was 3/8". Eventually it become harder and harder to find a resonably priced 3/8" stem valve, which means that oftentimes (especially the performance side of this work) you will end up going to the smaller 11/32" stem, or heck, even thinner. The obvious benefit there is the lighter valvetrain, and as metallurgy improved over the years the thin valves can actually take a pretty good beating too!
To put a 11/32" valve in your head you need the machinist to install a bronze valve guide liner/insert (they are actually different things, but for the purpose of this conversation consider them to be the same) where the extra thickness of the insert will allow you to go to a smaller stem size valve.
Now, as to why the machinist could not explain this to you is beyond me...which is why my recommendation in CAPS above.
Two comments here:
1) you are NOT stuck with the stock heads, you can get them re-worked by another machine shop, unless of course the previous work has messed up the castings so badly they can not be fixed, which I would find extremely hard to believe
2) the roller rockers should be fine on the stock diameter shaft, and unless you are running a massive spring the chances are that the stock thickness will be just fine, if anything I would actually worry more about having the right shaft with the correct oiling provisions to feed the non-stamped steel rocker arms (this is why the bananna grove shafts were so popular and effective)
So I'm not sure if you are oversimplifying this here, or whether the machinist himself has not given you the info. But, if it the machinist is NOT explaining precisely the reasons for not being able to go to 2.02" diameter intake, my only recommendation would be: FIND A NEW MACHINIST!
Here is the thing, originially (applicable to older small blocks) the valve stem size was 3/8". Eventually it become harder and harder to find a resonably priced 3/8" stem valve, which means that oftentimes (especially the performance side of this work) you will end up going to the smaller 11/32" stem, or heck, even thinner. The obvious benefit there is the lighter valvetrain, and as metallurgy improved over the years the thin valves can actually take a pretty good beating too!
To put a 11/32" valve in your head you need the machinist to install a bronze valve guide liner/insert (they are actually different things, but for the purpose of this conversation consider them to be the same) where the extra thickness of the insert will allow you to go to a smaller stem size valve.
Now, as to why the machinist could not explain this to you is beyond me...which is why my recommendation in CAPS above.
Two comments here:
1) you are NOT stuck with the stock heads, you can get them re-worked by another machine shop, unless of course the previous work has messed up the castings so badly they can not be fixed, which I would find extremely hard to believe
2) the roller rockers should be fine on the stock diameter shaft, and unless you are running a massive spring the chances are that the stock thickness will be just fine, if anything I would actually worry more about having the right shaft with the correct oiling provisions to feed the non-stamped steel rocker arms (this is why the bananna grove shafts were so popular and effective)
Alright I got more details here. He said rather than put the money into these heads as it will take more than we discussed. They used oversize valve stems rather than new guides they dont have hardened exhaust seats , springs wont work with new cam. Sell them for $650 +/- Buy alum for $1790 ish. These heads time we are done we would have $1300-1400 into them with parts to do what you want.
So that being said he found a set of aluminum heads that will work and keep compression in check. I also have access to 93 octane which will help matters aswell. So I guess now I'm spending more than what I anticipated. Given these new heads have springs that claim up to "0.525 of lift but are only single with dampeners, will they not be suitable for the xe274? Would changing the heads also mean I now need adjustable rockers for this cam? Furthermore, how bad would stock rockers work with this cam and what's the worst that can happen? Im lucky to put on 1000 miles a year on the car so it's not a daily.
So that being said he found a set of aluminum heads that will work and keep compression in check. I also have access to 93 octane which will help matters aswell. So I guess now I'm spending more than what I anticipated. Given these new heads have springs that claim up to "0.525 of lift but are only single with dampeners, will they not be suitable for the xe274? Would changing the heads also mean I now need adjustable rockers for this cam? Furthermore, how bad would stock rockers work with this cam and what's the worst that can happen? Im lucky to put on 1000 miles a year on the car so it's not a daily.
M_Body_Coupe
Well-Known Member
What are these heads and the specs? Used or new? What is meant by "will work"? Is that as in: they will work for what you intend to do with the engine/car combo?
I would recommend that clear specs be provided for the springs that come on these heads. Best would be to have a part number, could be something like a PAC spring, or it could be a Comp Cams, Crane, etc...lot's of choices out there.
Remember, the max lift is just one of the specs here, you always want to make sure that the springs have enough of a rate to control the cam lobe, and that you can get by comparing the specs for the springs that come with the head to the recommended Comp Cams springs for the camshaft.
Beware of the "oohhh...have I got a deal for you here" type of an opportunity, not saying that's what hapenning here, but don't buy a "cat in the bag".
The heads i was to have machined were from a fresh rebuilt short block 360, no idea who did the work as i had the block sitting for years. The heads that i will be buying are here:
Performance World 63171A SB Mopar 179cc Cylinder Heads pair (Complete)
I emailed Comp cams again and sent him the heads specs, he said i will be fine with the springs on the heads even though they are not duals. He didnt go into any details as to why they recommend dual springs though. so i guess now the only wild card is whether or not to use stock rockers with adjustable pushrods or get new rockers with new pushrods. Adjustable pushrods will be 200 USD, i wonder how long the stock rockers will last, lol.
Alternatively Mancini racing sells these for $274USD which will work with the stock shaft...saves some money but than i still need ball and cup pushrods which are an extra $100 USD
Mancini Racing - A Engine Adjustable Rocker Arm Set
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Those heads have 63cc chambers, just like every other small block Mopar alloy head on the market. Most of them are just shameless copies of the Edelbrock head.
I have no idea why your engine guy said those will work unless he thinks you have a lower compression ratio than what you believe you have.
Yeah well i think he gets a better deal on these heads as these are in canada and dont have to deal with exchange. Yes 63CC chambers like all the others, however he said with a "0.060 gasket and my current setup i should be looking at around 10:1 with the aluminum heads which will be fine. He also is recommending to get the Comp XE275HL which is higher lift but i think better for Chrysler apparently? I Have heard in the past that the XE274 is a Chevy Lobe, not sure if thats true or not.
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M_Body_Coupe
Well-Known Member
Here is a link to another Mopar forum with some video playback of this cam in a running motor => Anyone here using Comp Cam XE275HL
Yikes, .060", that is a lot of head gasket. The compression calculation I did was with the bog standard .039" head gasket. Hey, if it works.
Yes, the XE275HL was designed to use the larger Chrysler tappet. It is a rough idling cam though.
yeah i like the rough idle and it would take advantage of the 3000 stall, 3.91 gears and higher compression. I imagine with the higher lift and longer duration that it would sound louder/more aggressive aswell. Like i said its not a daily, just a cruiser once or twice a week on a sunny day. In Canada that only happens 4 months out of the year.
Sounds like you have a plan then. Full speed ahead and damn the torpedoes!
We expect plenty of build photos and video of the finished product.
haha for sure, i might go to the track one day with the wife if i have time. I might also have access to a dyno, so ill be testing it after.Sounds like you have a plan then. Full speed ahead and damn the torpedoes!
We expect plenty of build photos and video of the finished product.
One last thing though, i realized i only have the Performer intake not the "RPM Performer". Whats that really worth though a few HP? Im not sure if its worth upgrading at this point.
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kkritsilas
Well-Known Member
Performer won't flow any better than the stock intake, but it is significantly lighte (probably by 20 lbs.). Its not that the Performer is light so much as it is that the stock intake feels like it is made of lead.
So is the rpm miles better? Ive read the difference between the rpm and the air gap is minimal only worth a few HP.
jasperjacko
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Performer and the rpm are different. Performer has 318 sized ports and makes for quick throttle response and torque at lower rpms but will sacrifice some hp up top. I run the performer on my 360 and response is great, burns tires way to easy, but is not best for my cam. I used it to keep factory a/c. I have a torker 2 that I may try to see how it does.
I should probably look at swapping it with the cam that i have at some point in the future.
80mirada
Well-Known Member
the performer an be easily port matched to 360 heads, and it improves it greatly. but it is a good choice out of the box for a 318. the Performer RPM is an excellent intake, and has a traditional dual plane look wit an exhaust cross over. The RPM air gap has no exhaust crossover and runs cooler, but performance numbers are similar to the regular RPM
jasperjacko
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Port matching has to go very deep to be of any benefit on the performer. The rpm manifolds are taller and may have hood clearance issues depending on air cleaner used.
