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School me on Pistons

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School me on Pistons

Post #1 by 3OOford150 » Wed Apr 04, 2018 1:03 pm

I am currently in the process of accumulating parts to build my 300. I currently have a brand new set of H519P pistons dished. Can I obtain a 9.0-9.5 CR fairly simple. I plan of putting in this cam in.
Or does someone have another piston recommendation to obtain my goal without a ton of machining?


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Re: School me on Pistons

Post #2 by pmuller9 » Wed Apr 04, 2018 1:30 pm

There are 2 choices for non-metric hypereutectic pistons that will get you the most compression.
KB/Silvolite 1186H
SpeedPro/Sealed Power H519P

You have the H519P that has a 1.767 CD
The 1186H has a CD of 1.776 so a little less machining on the block deck.

It is not recommended to have a compression ratio higher than 9:1 with the Comp 268 because of the short advertised duration which is the same as the stock 300 cam unless you don't mind running on premium octane pump gas.

It wouldn't take much block deck machining to get 9:1 compression if you use the EFI head
Last edited by pmuller9 on Wed Apr 04, 2018 1:57 pm, edited 1 time in total.

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Re: School me on Pistons

Post #3 by bubba22349 » Wed Apr 04, 2018 1:46 pm

With those pistions the block would need to be zero decked and the head chambers would need to be at about 70 CC's to get a 9 to 1 Static Compression Ratio. Good luck :thumbup: :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: School me on Pistons

Post #4 by jason832 » Wed Apr 04, 2018 2:34 pm

My 300 has that exact cam and pistons. Carbed head milled 0.060 by PO, 1024 Head gasket, stock bore and block not milled. It diesels most times when I shut it off at full temp on 87 octane. 91 octane runs a bit smoother and lowers the dieseling. Not sure what my timing is at but it is set far enough back that it does not ping under low rpm high load.

Good thing is these pistons come weight matched when bought as a set and the rings I used E-229k came pre gapped and haven't had issues. Note these rings are different materials I think for the first two rings so don't mix them up.

My build ... heavy.html

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Re: School me on Pistons

Post #5 by pmuller9 » Mon Nov 26, 2018 9:51 pm

What combination of parts did you end up using?

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