Compression on KB107s with 63cc rpm Heads

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Chris70cuda

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What would the compression be on a engine with kb107s with the edelbrock rpm heads 63cc? Going on a stock 78 la 360 block
 
RustyRatRod said:
Deck height? Head gasket part number?
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The block is a 78 la 360 stock and will be bored .30 over. Felpro gasket set. I am looking at building this block. I want 380-400horse. Anyone have suggestions or complete list of proven components that will get me there with pump or premium gas?
 
To know exact the compression...we need to know how far down the piston are in the bore......felpro gasket head gasket...they make several head gasket that vary in thickness...

the couple of 360s that i have build with kb107 with eddy 63 heads....were around 10.6 to 1 and 10.2 to 1 depending on the deck height...and head gasket thickness...
 
You came in hot with post number two lol.

750 dp
Air gap intake
Rpm heads (if that's what you want to do)
A decent mild cam
Flat tops
Headers.

Good luck
 
Chris70cuda said:
The block is a 78 la 360 stock and will be bored .30 over. Felpro gasket set. I am looking at building this block. I want 380-400horse. Anyone have suggestions or complete list of proven components that will get me there with pump or premium gas?
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We still need the deck height and thickness of the gasket to give a more accurate answer.

But I have probably the exact same setup as you, I forget my deck height off the top of my head but I estimated that mine was around 10.5:1. The 63cc heads are closed chamber heads which are better for higher compression.

In mine i'm running an LA 360 block, RPM 63cc heads, comp XE268-h cam, weiand dual action plus intake, dougs headers and so on... I'm told it should be a pretty good setup. It should make at least 350hp and I wouldn't be surprised if it made more. More power can be made with a bigger cam. Could be off on the power estimation however.
 

Nevermind. I'm sick of these teeth pullin questions.
 
Chris70cuda said:
What was the deck height and gasket thickness you used to get 10.2 on your 360?
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off the top of my head...without looking at my notes....the pistons were down about .022...and I used a .028 thick head gasket....MR Gasket 1121G....
 
70aarcuda said:
off the top of my head...without looking at my notes....the pistons were down about .022...and I used a .028 thick head gasket....MR Gasket 1121G....
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Well I apologize for the stupid question. I have never built an engine. I just want to get my cuda back on the road. Basically I was looking for information to get a 380 horse 78 360 LA original not touch block built. Just need to know what to buy and what to tell the machinist what to do.

Already have ported j-heads with 2.02 / 1.60valves just need to go from there
 
It wasn't stupid in the least. It just lacks information. Get all the missin info and we can help.
 
You will need 80.1 cc clearance volume for 10.2 compression. This includes the piston drop, head gasket, and combustion chamber in the head.

With the 63 cc head, it leaves you 17.1 cc for the head gasket and piston.
 
Chris70cuda said:
Well I apologize for the stupid question. I have never built an engine. I just want to get my cuda back on the road. Basically I was looking for information to get a 380 horse 78 360 LA original not touch block built. Just need to know what to buy and what to tell the machinist what to do.

Already have ported j-heads with 2.02 / 1.60valves just need to go from there
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Welcome! Looks like you just joined. No questions are stupid. Lots of very knowledgeable people willing to help but you'll find a few that are quick to jump you if you dont ask your questions properly or give vague info. Dont sweat it, people just want to help but some times alot more info is needed to answer your questions properly. I think some forget that sometimes people are complete novices and here to learn and some of the info we are asking for sounds like a foreign language. I couldn't have got my car were it's at without the info I got here. You'll learn a lot.
 
Yeah we get a lot of "what cam do I need, I got a red engine?" So if somebody throws out a semi smartass answer don't hold it against them. As said, no questions are stupid we just need more info here.
 
For 380-400hp from a 360 you don't need ported heads or RPMs. You need the KB107s, stock heads with a good performance valve job, and a cam with a modern lobe and around 230° duration at .050.
Now - first you said you had 63cc chamber RPMS - now it's ported J heads..
The RPMs need the right gasket - that's the Fel Pro 1009 and it's .039" compressed. But - the deck height on mopar blocks is almost always off, and to the taller side. So if the KB107s are installed and the block is square decked to zero deck the pistons you will end up right around 10.9, and you need to run a cam around 235-240° @ .050 to keep it pump gas friendly. If they are in at zero deck with J heads that have tulip valves and normal chambers, and a felpro blue head gasket at .045 it will be around 9.6:1 and you will want to runa cam in the 225° @ .050 range. In either case it should make what you want for power.
I would suggest you find a machine shop you can trust, that has a good record with the local racers (not the cruise night guys) and talk to them about what you have and what you need. Then we can toss thier ideas around. what you want is not hard or expensive to do.
 
Thanks for the advice. I am going to stick with my j-heads for this build. What brand or part number of cam would you use for the 225 @ .50 range?

Anyone have some unused KB107s for sale for a 360?
 
Chris70cuda said:
Thanks for the advice. I am going to stick with my j-heads for this build. What brand or part number of cam would you use for the 225 @ .50 range?

Anyone have some unused KB107s for sale for a 360?
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Throw up a wanted ad in the classified section.
 
What have the heads had done to them?
Those pistons are $266 from Summit. By the time you get a "deal" on brand new pistons and had them shipped to you - you'll be very close to that price. You might want to just buy them new - then you have the assurance if they get damaged in shipping they will be replaced.
 
When I was buyying pistons I went with the speed pros. I heard some funky things with the kb rings. Also heard that the Keith black pistons are heavier. I never put them on a scale though so I can't say for sure
 
doogievlg said:
When I was buyying pistons I went with the speed pros. I heard some funky things with the kb rings. Also heard that the Keith black pistons are heavier. I never put them on a scale though so I can't say for sure
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the KB pistons have a thinner skirt on them. The 360 we were building for my son's 360 came with KB pistons, the #5 piston skirt broke when I picked it up - not hit at all, just chipped.

Speed Pro has a much thicker skirt, so I went with those instead.
 
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