351C Pistons
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Joined: Feb 2004
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From: Westfield, North Carolina
351C Pistons
Does anyone make a set of pistons that gives decent compression for open chamber 2v heads? Im not looking to build an all out race motor, I just want a stout Cleveland and can't find many piston selections. I may end up trying to find better heads , but I wanted to use these since I just put alot of money in having them redone.
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Joined: Feb 2004
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From: Westfield, North Carolina
Well what would be a good compression ratio for open 2v heads? I was thinking manybe 9.5 to 10 correct me if Im wrong. I may have the wrong head for what I want, this motor is going into a 71 Mustang and every one has told me that the 2v head is what I needed for street performance. I was looking for decent milage and a solid 350 hp. If thats not possible tell me what I need then. Im new to the 385 engines so I need all the help I can get. 
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From: Temperance,MI
Well for 351C you dont need tons of compression the Speed Pro H555Ps with the open chambers make 8.83:1. The edelbrock numbers are with stock compression. With thoes pistons, good intake, headers, and a good cam you will hit your mark. You could run the quench australian heads and if you can keep it under 10:1 you can burn 87 in it .
TMI has enlightened me on the quench heads there a definate plus, much more effiecent combustion chamber for more compression with less need for high octane as long as the pistons are a zero deck piston to take advantage of the quench.
335series is cleveland, 385 is the big blocks
Curtis
TMI has enlightened me on the quench heads there a definate plus
, much more effiecent combustion chamber for more compression with less need for high octane as long as the pistons are a zero deck piston to take advantage of the quench.335series is cleveland, 385 is the big blocks
Curtis
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From: Westfield, North Carolina
Sorry about the 335/385 mix up. So if I use a piston like so, can I go ahead and use my 2v heads and maybe later change over to Aussie heads if I want more out of it?
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From: Delaware
CHI has aluminum 2V heads fully assembled for under $2000.00. They flow 300 CFM @0.600 lift. I believe that they have 64cc chambers. With flattop pistons (3cc valve relief) and 0.020 deck clearance, the CR is 10.0:1. If you hook this up with a moderate cam with 63 degrees Intake valve closing you will have a Dynamic Compression Ratio of 8.1:1. Since these are fast burn heads, you may get by with less than 93 Octane fuel. These will put the muscle into that Mustang.
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From: iowa
i like the trw/sealed powed L2379F30. Forged pistons for $240 is a damn good deal and about worry proof for the street. Compression would be like low 9's. piston specs: 1.5 cc dish, 1.647 comp height.
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From: Westfield, North Carolina
Well after much looking around I think Im going to use the KB-177-8's. They seem to give 9.5 cr, and shouldnt bump it to high if I ever decide I need to switch to the aussie 2v's. Im hoping this build wont put me in the poor house like my FE almost did, but its still a great engine.
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Joined: Feb 2004
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From: Westfield, North Carolina
How larger of a cam? I know I pulled flat top pistons out of the stock engine and it seem to run fine before on 89 with 2v heads. Those KB's look almost identical to the stock style pistons with 2 valve reliefs. Hopefully someone knows the answer to all of this so I can get on the right track here.
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From: Delaware
With 75.4 cc heads and zero deck pistons with 2cc valve relief and +0.030 bore, you get 9.5:1 CR. If you use a cam with Intake Valve Closing (IVC) of 58 degrees ABDC, you get about 8.0:1 Dynamic Compression Ratio. This should be OK on 91 Octane or better. A longer duration cam with later IVC will bring the DCR even lower, and allow 89 Octane.
If you put Aussie heads on this same motor, you Static CR goes to 11.65:1. You will need a cam with later than 75 degrees ABDC IVC, to get the DCR down to 8.5:1 or less. This is the limit for pump gas with quench. A cam like that will have poor street manners.
If you put Aussie heads on this same motor, you Static CR goes to 11.65:1. You will need a cam with later than 75 degrees ABDC IVC, to get the DCR down to 8.5:1 or less. This is the limit for pump gas with quench. A cam like that will have poor street manners.
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From: Westfield, North Carolina
Ok so Ill ask one more piston question I think 
.... which would be prefered if I didnt like the power of the 2v heads and switched over later to the aussies? The dished KB's or the flat tops? What Im saying is, Im not sure if I will switch to the Aussies , I wont if the power of the 2v's make me happy , but will switch if they fall short. Sorry for sounding confusing.
.... which would be prefered if I didnt like the power of the 2v heads and switched over later to the aussies? The dished KB's or the flat tops? What Im saying is, Im not sure if I will switch to the Aussies , I wont if the power of the 2v's make me happy , but will switch if they fall short. Sorry for sounding confusing.
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From: Delaware
The only thing that Aussie heads offer is higher CR and quench. If your CR is already high enough with open chamber heads, you do not need the Aussie heads. The Aussie head flow is no better than the heads that you have. Use your 9.5:1 pistons and enough cam to keep you DCR reasonable, and spend the money on improving the head flow of your heads.
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From: Temperance,MI
So if I run the open chamber heads, with the Speed Pro H555Ps and the cam CamCraft is going to do for me I wont be happy? I'm planning to do alot of towing with it so I don't want to have to deal with high octane fuels and its going to be on fuel injection too. I mean with the closed chamber heads on TMIs he was burning 87 with around 9.7:1-9.8:1 with 30degrees of advance. I'm confused and lost in this debating on just running the opens with 8.83:1.
Thanks
Curtis
Thanks
Curtis
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From: Delaware
Give me all your specs, cam lift, seat to seat duration, piston CH, dish size, head flow, bore, stroke and application. I'll run the numbers for you.
Quench is only worth about 0.5 points in CR. You can get more power at mid RPMs from improvement in head flow, than from 0.5 points in CR.
Quench is only worth about 0.5 points in CR. You can get more power at mid RPMs from improvement in head flow, than from 0.5 points in CR.