building a 360

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BobsDart said:
Good choice on the cam. Had it in my 360, nice power and lopey idle. Later swapped it for the compcam XE 274. Hate to say it but Old School MP cam ran as good as the New school compcam.....had lifter problems, so went back to old school MP solid cam and haven't looked back... minimum 650 carb..........

Bob
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Are you sure your talking about the same Mopar cam? I ask because the one he listed is not a solid cam, like you said you went back to. Comp did have some lifter problems 2-3 yrs. ago. I also used a XE274 in a 360 and had 2 sets of lifters go bad right off the bat. First set only lasted about 150 miles and the second set only lasted about 500 miles before they wouldn't pump up after sitting over night. I heard their USA lifter supplier was on strike and they bought lifters from China and the tolerance was crap. Don't know if it was true but it made sense. They've got it straightened out now.

BTW: The comp XE274 isn't any more aggressive than an old school MP cam so as long as you don't need more exhaust duration the Comp probably won't make more power. Comp's HL series are a little more aggressive. About = to the Lunati Voodoo's.
 
I'm guessing your piston will probably sit .020" down in the hole, that's 4cc's, and your valve reliefs show +10cc's on summit's info page, your head gasket will be 8cc's. your volume at TDC will be 65 + 10 + 8 + 4 = 87cc. Volume of stroke = 752cc. Volume at BDC = stroke + volume at TDC which is 839cc. Compression ratio is 839/87 which equals 9.6 to 1. Sounds like a good compression ratio according to my math, just ensure you actually have 65cc heads and not some heads that are 74cc. If you had 74cc heads your compression ratio would drop to 8.8 to 1. Here's a site where you could confirm what your chamber size is supposed to be (assuming no milling of heads):

http://mopedia.org/3418915

I think the only area you'd not be happy with is your torker ii intake is gonna be weak below 3k' rpm. It really wakes up when you get to high rpm, you might want a dual plane on it when you get the cash. Rumble - Now that I think about it I haven't run that edelbrock 750 on my rpm manifold yet, just on my torker ii, it might not stumble now that I have an rpm manifold on it.
 
juvat said:
I'm guessing your piston will probably sit .020" down in the hole, that's 4cc's, and your valve reliefs show +10cc's on summit's info page, your head gasket will be 8cc's. your volume at TDC will be 65 + 10 + 8 + 4 = 87cc. Volume of stroke = 752cc. Volume at BDC = stroke + volume at TDC which is 839cc. Compression ratio is 839/87 which equals 9.6 to 1. Sounds like a good compression ratio according to my math, just ensure you actually have 65cc heads and not some heads that are 74cc. If you had 74cc heads your compression ratio would drop to 8.8 to 1.
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Nice math skills

I am lazy and use the CR calc at kb-silvolite.com

Using the figures stated above and in original post your SCR would be 9.564 and your DCR 7.899 using an Intake Valve Closing value of 45 and a common .040" compressed thickness head gasket with a 4.1" bore

All else being equal, switching to an SCE 69062 head gasket with a .021" compressed thickness and a bore of 4.060" would bump your static compression to 9.993 and your dynamic to 8.245 with a .041" quench

For the same money as a set of gaskets costs, especially if using cometic, you can have your block square decked to zero your pistons and run a common, inexpensive .040 thick gasket AND set proper quench

Just thinking out loud here...
 
Iran a 360 with 9.0 pistons 484/280mp cam x heads ld340 5204 hooker super comps got more bang for my buck in that little motor than any thing i ever built i had a 3500 stall turbo action reverse valve body extra large raditor &trans cooler i had 391 gears i wish i would have use a 373 if i could got one back then i would go with a ld340 intake or a edelbrock rpm2 loose the single plane since it is a street car please order you a mopar engine &mopar chassis book from jegs,manicini they are around twenty something each the key is to use match parts you wont be dissappointed in those books that way you can figure out what your needs are not someone stuff that didnt fill there needs:-D
 
juvat said:
I'm guessing your piston will probably sit .020" down in the hole, that's 4cc's, and your valve reliefs show +10cc's on summit's info page, your head gasket will be 8cc's. your volume at TDC will be 65 + 10 + 8 + 4 = 87cc. Volume of stroke = 752cc. Volume at BDC = stroke + volume at TDC which is 839cc. Compression ratio is 839/87 which equals 9.6 to 1. Sounds like a good compression ratio according to my math, just ensure you actually have 65cc heads and not some heads that are 74cc. If you had 74cc heads your compression ratio would drop to 8.8 to 1. Here's a site where you could confirm what your chamber size is supposed to be (assuming no milling of heads):

http://mopedia.org/3418915

I think the only area you'd not be happy with is your torker ii intake is gonna be weak below 3k' rpm. It really wakes up when you get to high rpm, you might want a dual plane on it when you get the cash. Rumble - Now that I think about it I haven't run that edelbrock 750 on my rpm manifold yet, just on my torker ii, it might not stumble now that I have an rpm manifold on it.
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Weel I am thinking of buying a new intake.As for the cc of the heads I remember checking the numbers and I think they are 65 cc.As soon as I get them back from the machine shop I will check them again.I asked the shop to check but they still havent checked so I will do it myself.I will use the old suringe trick and fill it with liquid and see how many cc's it takes to fill the bowls.As for the carb I was thinking of a 650 or 670 holly dual line.Also how do you tell the thickness of the head gasketts,I ordered a felpro set from jegs.Buy the way thanks for the info and great math skills.
 
Rumble had the thickness info on head gaskets, I think most of them are going to be around .039" thick, that's what I plugged in for the calculations. You can get .029" for more compression (I think Mopar Performance makes them), but I'm thinking you're sitting okay with compression. You should have that machine shop check the head volume for you, you're paying them anyway. That would be a project that would end up taking more time than you're thinking it will. I would go with a 750 double pumper for the carb. It would run great with a 650 or 670, but when you stroke it later or re-cam it and bolt on ported heads you won't have to buy another carb. With my rpm air gap and 750 carb the throttle response is just fine.
 
juvat said:
Rumble had the thickness info on head gaskets, I think most of them are going to be around .039" thick, that's what I plugged in for the calculations. You can get .029" for more compression (I think Mopar Performance makes them), but I'm thinking you're sitting okay with compression. You should have that machine shop check the head volume for you, you're paying them anyway. That would be a project that would end up taking more time than you're thinking it will. I would go with a 750 double pumper for the carb. It would run great with a 650 or 670, but when you stroke it later or re-cam it and bolt on ported heads you won't have to buy another carb. With my rpm air gap and 750 carb the throttle response is just fine.
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Well I wasnt able to start the build yet.Here is the latest.I just run the head numbers again and they are 68cc,so I am having the shop mill the heads 20 and hopefully this will make up for any loss that occured with my mistake on the head cc.If you could calculate the compression ratio for me with the newest info that would be great.The machine shop said with out milling the heads I would be at a 8.71 compression ratio.I hope the milling will raise the ratio back up to 9.5-1 at the least.I did a little research on the head numbers and the web page says they are not 68 cc they are 65cc.I am afraid now that milling the haeds 20 may raise the compression ratio to high and I will have the run high octain fuel.Well its to late for that because they milled them today so he said.I just wonder what the comp ratio will be with 65cc heads and milled 20.Thanks,Eddie here is the link where I found the info on the heads.Head nimbers are 3671587 and there is a -12 after the numbers. http://www.cowtownmopars.com/CastingNumbers.html
 
mynumber38 said:
Well I wasnt able to start the build yet.Here is the latest.I just run the head numbers again and they are 68cc,so I am having the shop mill the heads 20 and hopefully this will make up for any loss that occured with my mistake on the head cc.If you could calculate the compression ratio for me with the newest info that would be great.The machine shop said with out milling the heads I would be at a 8.71 compression ratio.I hope the milling will raise the ratio back up to 9.5-1 at the least.Thanks,Eddie
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Just wanted to add this link http://www.cowtownmopars.com/CastingNumbers.html although the machine shop said my heads were 68cc,this link says they are 65cc.If this is true the compression ratio may be to high if they mill the heads 20 but I guess its to late now.If you have any insite let me know.This is the head numbers 3671587 there is a -12 after the number.They are stamped 360 as well.
 
I think that would drop your cc's by 4cc's, which would bring your compression up about a half point from 8.71:1. You're probably looking at about a 9.25:1 compression ratio which is good for pump gas. You might have to mill your intake to get everything to line up. Here's a site with alot of info - http://www.mopar1.us/mill.html. I would ask your machine shop if you're going to need to mill the intake, or maybe somebody on here has some more info about it. I didn't have to mill my heads for compression, so they'd have better info. Or, I guess you could always bolt on your intake when you get your engine home, and if it doesn't line up just take the intake back to the machine shop and have them mill it.
 
mynumber38 said:
Just wanted to add this link http://www.cowtownmopars.com/CastingNumbers.html although the machine shop said my heads were 68cc,this link says they are 65cc.If this is true the compression ratio may be to high if they mill the heads 20 but I guess its to late now.If you have any insite let me know.This is the head numbers 3671587 there is a -12 after the number.They are stamped 360 as well.
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Look at your link again. It doesn't say the heads are 65 cc's. It says they are from 65-73 cc's. You can NEVER go by advertised ratings on most anything. You always have to measure it yourself. There are a few things that affect the chamber size including, valve type, how many times the valves have been ground (every time the valves are ground they drop lower in the hole making the chamber bigger). I'm gonna guess and say from experience your heads were more like 70-72 cc's to start out. I have yet to measure a stock head and find less that 70 cc chambers.
 
juvat said:
I think that would drop your cc's by 4cc's, which would bring your compression up about a half point from 8.71:1. You're probably looking at about a 9.25:1 compression ratio which is good for pump gas. You might have to mill your intake to get everything to line up. Here's a site with alot of info - http://www.mopar1.us/mill.html. I would ask your machine shop if you're going to need to mill the intake, or maybe somebody on here has some more info about it. I didn't have to mill my heads for compression, so they'd have better info. Or, I guess you could always bolt on your intake when you get your engine home, and if it doesn't line up just take the intake back to the machine shop and have them mill it.
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I did talk to the shop and they said I will be fine milling the heads 20.I guess I will see what happens.I am totaly lost when it comes to figuring out a set of heads.But hey I do appreciate all the help from you guys.Thanks,Eddie
 
fishy68 said:
Yeah Magnum heads are smaller chambers because they are closed chambers. We're talking open chamber LA heads here. Big difference.
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So bottom line,are these heads going to do what I want them to do that being the engine making 325 to 330 hp or more.Or what heads will I need to run without droping alot of $$.Can I go the the scrap yard and get a set of newer magnum heads or?
 
mynumber38 said:
So bottom line,are these heads going to do what I want them to do that being the engine making 325 to 330 hp or more.Or what heads will I need to run without droping alot of $$.Can I go the the scrap yard and get a set of newer magnum heads or?
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Your 587 heads should make 325 hp easily as long as the rest of the parts are matched properly. Magnums would probably make some more power but they were very prone to cracking between the seats so you have to watch them carefully as to not get a set of boat anchors. Also if you wanted to switch to magnum's there are valve train differences you'd have to address.
 
fishy68 said:
Your 587 heads should make 325 hp easily as long as the rest of the parts are matched properly. Magnums would probably make some more power but they were very prone to cracking between the seats so you have to watch them carefully as to not get a set of boat anchors. Also if you wanted to switch to magnum's there are valve train differences you'd have to address.
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Well I think I will just stick with the heads I have since they were just machined and have all new parts.They replaced the guides,I am replacing the springs so they are good for a 510 lift.I may change the intake to try and get a closer match to the cam I am running.I think the torker 2 is a higher rpm intake like 2000-6000 rpm.Although I will have to double check the cam rmp range.I may have the intake milled to match the heads although it should be fine.I still may try to open up the intake and heads to match the gasketts.This should make a bit more performance.
 
mynumber38 said:
Well I think I will just stick with the heads I have since they were just machined and have all new parts.They replaced the guides,I am replacing the springs so they are good for a 510 lift.I may change the intake to try and get a closer match to the cam I am running.I think the torker 2 is a higher rpm intake like 2000-6000 rpm.Although I will have to double check the cam rmp range.I may have the intake milled to match the heads although it should be fine.I still may try to open up the intake and heads to match the gasketts.This should make a bit more performance.
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Sounds like a good plan. Only thing I'll add is just port matching the heads to intake really does very little. Alot more power is in bowl work but that can be very time consuming and if you already have the valves ground you better have super steady hands cause it's easy to nip a seat and have to have it re-ground. Ask me how I know.:cwm10:
 
fishy68 said:
Sounds like a good plan. Only thing I'll add is just port matching the heads to intake really does very little. Alot more power is in bowl work but that can be very time consuming and if you already have the valves ground you better have super steady hands cause it's easy to nip a seat and have to have it re-ground. Ask me how I know.:cwm10:
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Yea,Im just worried about the compression ratio.I dont know where its going to end up,8.71-1 or 9.25-1 Is there that much of a difference in performance I mean thats not to big of a difference.
 
mynumber38 said:
Yea,Im just worried about the compression ratio.I dont know where its going to end up,8.71-1 or 9.25-1 Is there that much of a difference in performance I mean thats not to big of a difference.
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That does make it hard to pick a cam. If you have the heads off it isn't hard to figure the compression ratio. A half point of compression is worth a decent amount of performance but it does vary with the selection of other components. I'd guess their might be 12-15 hp diff. between 8.7 and 9.25 to 1 compression. Maybe some of the other guys will chime in on their thoughts on that.
 
fishy68 said:
That does make it hard to pick a cam. If you have the heads off it isn't hard to figure the compression ratio. A half point of compression is worth a decent amount of performance but it does vary with the selection of other components. I'd guess their might be 12-15 hp diff. between 8.7 and 9.25 to 1 compression. Maybe some of the other guys will chime in on their thoughts on that.
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The heads are off right now.How would I go about figuring out the compression.Also is there anything I can do to the heads to make them more performance minded.
 
Use the CR calc at kb-silvolite.com, it will show you what you need to know to complete the formula like deck height, chamber volume, piston volume, etc
 
octanejunkie said:
Use the CR calc at kb-silvolite.com, it will show you what you need to know to complete the formula like deck height, chamber volume, piston volume, etc
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So all in all do you think with the 40 over flat tops with valve rieliefs,the 274-484 cam and the stock 587 heads with the torker2 or air gap intake with 700 to 750 holley will get me to my goal of 325 to 330 hp.
 
mynumber38 said:
The heads are off right now.How would I go about figuring out the compression.Also is there anything I can do to the heads to make them more performance minded.
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You need tools for checking the chamber cc's. I don't know if you do E-bay but if you do here is a cheap kit that'll do it. Just make sure and clean the chamber and valves good so you get an accurate reading.

http://cgi.ebay.com/ebaymotors/ws/e...0395360749&viewitem=&sspagename=STRK:MEWAX:IT

Then you check to see how far down the hole the pistons are. There are a few ways of doing it but I find TDC with a dial indicator then lay a straight edge across the deck surface and stack feeler gauge blades until you reach the piston then add them up and that's how far down the hole the piston is. If the pistons have valve reliefs that'll add cc's to the equation. They vary so it's best to look up the pistons and see what it's rated at since you can't really get in and cc them easily with the lower end together. Then you go to the website octanejunkie provided and plug in all the numbers and it'll give you your compression.
 
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