I recently found this, and want to make sure it is an okay set up

300 i6.
Bored to fit 390 stock flat top with valve cutouts.
.10 and .10 on the crank.
Steel timing set

Cam
204/214
.449/.473
Melling rv cam? Or crevite not sure.

Head
No pp
Hardened 1.94 and 1.60 stainless valves
Rhoads roller lifters
Sbc 1.75 rockers
Hvop oil pump
Apr studs

 

Offy dp
Holley 450 q-jet?
And Hedman headers.

Used felpro hg and I have no idea as far as compression or cc in the chamber
.01 taken off head to true up.

What does this sounding as far as cr?
How will this be in power department.
What would you pay for this motor unbroken in.

 

Rhoades roller lifters? For real?

 

That's what in it. If I do get this, I'm taking it to my machine shop and having them check it. Or I might just talk him into letting go of the head.

 

Forgot to mention new clutch kit and master cylinder and zf5 2wd
If I get this, I'll divorce my t case. You can't find good zf5 4x4 in my area under a grand

 

Also has a 240 head and 460 radiator. And 38gal tank. This might could work out.

 

That's going to be really high compression.

 

That's what I'm worried about.Would I be able to mill a .02 or so off the piston?

 

First off, I'm confused. Is this some engine on Craigslist or something that you're considering buying? You're leaving a lot of details out here. You're asking if this engine is right for you and we don't know what it is or what you want. My concern is that you're worried about compression ratios because it sounds like you're wanting to actually drive this thing around town or something. I can tell you right now from the compression that this is a performance engine. You'll need high octane fuel.

Below is the OEM piston. The dish is rather large. Flat tops obviously eliminate that dish, raising the compression a lot. If I recall correctly, flat top 352 pistons in a 300 work out to just over 10:1 static compression. The RV cam probably gives you a high dynamic compression - again, requiring high octane.



Secondly, yes. You can machine whatever you want, but piston material is important. Eutectic, AKA cast pistons aren't all that great for machining because of the sand content. Forged or billet can be machined all day long. So, yes, you can machine 0.020" off the pistons.

 

Yes it is on cl.
Is there any easier way to get take lower cr? I'm not sure what the pistons are.
I'm planning on having a shop tear it down, to check it. I'm calling his shop later when the day starts.
It's for my dd truck.

 

I can't be precise without knowing what head gasket was used, but 390 flat top pistons with a 4cc recess and 4.052" bore in a 300 with a 3.98" stroke and a 76cc combustion chamber, giving a deck clearance of .0253, the static compression is just under 10.6:1.

For those that aren't OP, here is the Craigslist ad. 1985 Ford 300L6 new on stand-390 pistons

Here is the camshaft information.



The 390 and 300 pistons have the same wrist pin size of 0.9752", but what about the connecting rods. Are they the same length at 6.210"? That's the last bit of information I'd need to calculate the dynamic compression ratio and give OP a final word of judgement on what kind of octane he'd need.

 

I will try and find out.
Hg was a .039 compressed felpro
Says everything else is stock or reground. And I believe the way something was worded, he used stock 300 rods.

 

If the rods are the same length, the effective stroke is 3.82", giving a dynamic compression ratio of 10.2:1, which is very high. Can someone say race fuel?

That, and with the cam specs and 1.75:1 rockers, you're not getting any fuel efficiency. I don't know why he threw on a Holley Spreadbore. It's a performance engine.

 

I don't know many people that put a 450 on a 300 that's stock, let alone this built.
Also Rhoads roller lifters on an engine that might see 5, 5.5k?
What if I rebored my stock engine threw a cam and that head on it. How would that come up out as far as cr?

Thank you. This is the reason I ask these questions to clarify

They are hyper-e Pistons made by... awaiting reply.
Since this had arp studs all the way, could I pull the felpro and get a thicker gasket?

 

Compression Ratio Calculator | Tools | Diamond Racing Pistons

according to this, if i change to a edelbrock gasket with a 4.1 od and .047 compressed itll drop from a 9.93 to a 9.45 and then if i can squeeze 2cc out of the combustion chamber to 78cc, ill get a 9.28.

my buddies 1974 corvette has a 9.0;1 cr from factory and runs 87 octane no problem.