HELP GUYS!!! Dynamic Compression VS Static compression...400 Cleveland, Pump Gas!

For starters, maybe a lot of us should read this site....unless you are already an expert...and I hope that you are without this site!

http://cochise.uia.net/pkelley2/DynamicCR.html

I will use Larry Madsen's build (MonsterMach) for my comparisons because mine is so strikingly similar. He has 11:1 STATIC Compression ratio. His advertised duration on his cam is 284* This duration yields an, 8.732:1 Dynamic Compression ratio--and he is getting away with pump gas 91 octane.

Because I have cast pistons in my 351 C, it has me nervous to rev it out to its full potential...so, I can either A.) put forged pistons in my current block, or I could do a 400 Cleveland in my mustang. It will fit as it is a 73. The only bad thing, is that the motor would HAVE to run on pump gas as it is a street car that sees track time. Knowing that....

I am going to say:

*4.03 Bore
*gaskets: .038
*Heads 60cc... I know they are larger but I am not sure how big--CCing them would be a good idea, but, they have NOT been milled, only belt sanded--I am still using 60cc as a guide point as that is what MonsterMach has his heads as.
*Piston to Deck will be 0 to assure proper quench.
*Valve reliefs are 2cc (I was unaware of this) on a Cleveland...and if they can be fly cut cheaply, how much can the be cut? It would be nice to get a few more CC's out of them to lower the compression.
*Cam as I said will be an Advertised Duration of 310*

Using the DCR calculator on this site, I determined I would have to use a cam with, around 310* advertised duration and 320* on the exhaust (unless we should go even 310 310?)

This will give me an 8.621:1 Dynamic Comperssion Ratio. Now, here is the main question(s): Since My stang runs on 91 Octane with a 8.732:1 DCR, is it safe to say the 400 with my heads will run on pump gas as well?

Larry, (MonsterMach) brought up Volumetric efficiency and we talked about that...I do not understand enough about it to really say anything about it.

Okay, lets help me out...PLEASE! Thanks guys!

Jeff Given

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Jeff Given
Sacramento State, Home Town Corona, CA



<font size=-1>[ This Message was edited by: MightyMach on 5/29/03 4:05am ]</font>

<font size=-1>[ This Message was edited by: MightyMach on 5/29/03 4:05am ]</font>

8.621:1 is definately high for a dynamic comp ratio with pump gas. i was paranoid building a stroker che#y with 8.25:1 DCR. but if it works let me know your tricks so i can build me one.
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as I said, 8.732:1 is getting away with pump gas in a 351 Cleveland...check out MonsterMach's build sheet!

Jeff Given
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MightyMach I think you really helped me out if I am correct i figured at 8.17718 please let me know if I am doing this right here is my crane cam spec card online http://dab7.cranecams.com/SpecCard/D...1=Display+Card
it would really mean alot if you can verify this I do not read cam cards well or actually understand them yet this has been a great learning lesson the rest is:
stroke 3.78
rod 6.448
bore 4.23
gasket thickness .041
gasket bore 4.40
I dont know my deck height but it is in a little so I have been using .005
dome piston 11.4
if this is too much no problem I was just about to buy new pistons and rebalance the motor all over due to I want to use my alum. heads not the 427 iron FE heads it would really mean alot MonsterMach was refering to something similar but I could never figure the Dynamic James302 gave me the formula but it was over my head and that calc. seemed to fit it

Robert
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<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2003-05-28 16:40, 69Fstbk wrote:
MightyMach I think you really helped me out if I am correct i figured at 8.17718 please let me know if I am doing this right here is my crane cam spec card online http://dab7.cranecams.com/SpecCard/D...1=Display+Card
it would really mean alot if you can verify this I do not read cam cards well or actually understand them yet this has been a great learning lesson the rest is:
stroke 3.78
rod 6.448
bore 4.23
gasket thickness .041
gasket bore 4.40
I dont know my deck height but it is in a little so I have been using .005
dome piston 11.4
if this is too much no problem I was just about to buy new pistons and rebalance the motor all over due to I want to use my alum. heads not the 427 iron FE heads it would really mean alot MonsterMach was refering to something similar but I could never figure the Dynamic James302 gave me the formula but it was over my head and that calc. seemed to fit it

Robert

</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

Still need the head cc, and the pistons cc...then I can get it for you [img]/phpBB/images/smiles/icon_wink.gif[/img]

Pretty bitching calculator huh?

Jeff Given
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Yes it is and I do think it may save me the dome is 11.4cc on the piston and the chamber is 76cc I really do appreciate this

Robert
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getting a 9.78:1 DCR....the pistons are killing you. The bore is also killing you a 4.03 would give you a 8.9:1 [img]/phpBB/images/smiles/icon_evil.gif[/img] Glad to help out, more than happy to help more [img]/phpBB/images/smiles/icon_smile.gif[/img]

Anyone got any info on the 400 Cleveland?

Jeff Given
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An icewater\methanol (or ethanol) injection setup might cure that, but would most likely only be for the drag strip

That hurts [img]/phpBB/images/smiles/icon_cry.gif[/img] I guess I was typing in the wrong things I thought it was too good to be true thanks I think I am going to sell the 427 and use the 428 I cant afford any more its either that or find some 90cc heads thanks again

Robert
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Come on guys... [img]/phpBB/images/smiles/icon_frown.gif[/img]

Jeff Given
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