Rebuild

[Dusty1]

Mike, the heads are ready to be bolted on. I told them 484 lift and they installed these springs. Thanks

[Topcat]

Mike, the heads are ready to be bolted on. I told them 484 lift and they installed these springs. Thanks

Then the only thing left is to make sure you get the valve to piston clearance checked. With your lift, I doubt it will be an issue. but it's good to know what it is prior to the final bolt up.

[72bluNblu]

I thought this motor had 10.5 to 1 compression stock?

Uh, probably not.  While that may have been the spec, I seriously doubt that many of even the '68 340's had a compression ratio that high from the factory.The chambers on most of the stock heads were larger than the specified 65cc's. I'm finally almost finished building my '68 340, and with aftermarket pistons (KB 243's) and heads that cc'd right at 65 my compression ratio is at 9.9:1, even with the tops of the pistons .018" out of the hole.

What kind of pistons are you planning on running? Stock cast, hypereutectic, forged? Keep in mind that on a '68 340 your pistons should actually be above the deck. Spec was .018", which is where mine are. Shouldn't be an issue running stock heads and that cam, I'm running a Lunati 60404 (.513/.533 lift) and don't have clearance problems. Although, the KB 243 hyper's that are in my engine have some pretty serious valve pockets. If you are getting stock pistons, make sure you get the early high compression version, and not the later low compression type.

A Sealed Power cast piston (Z428)


Kieth Black hypereutectic (KB243)



Speed Pro forged (ZL2316)

[Dusty1]

Thanks! More knowledge, I love it. I just learned I'll be getting pistons, don't know what type yet. Gathering info from the vault I want to keep the compression up. There's always a new temptation. I was offered a 6.1 hemi today out of a challenger. $1500 Ugh!

[72bluNblu]

Thanks! More knowledge, I love it. I just learned I'll be getting pistons, don't know what type yet. Gathering info from the vault I want to keep the compression up. There's always a new temptation. I was offered a 6.1 hemi today out of a challenger. $1500 Ugh!

Wow! That's a sweet deal, most of the hemi's I see around here are listed at $3 to 4k! 

Of course, there's still a lot of money to spend on a late model hemi just to get it adapted into one of the e-bodies. Headers, intake manifold (or a controller for the fuel injection), transmission adapters or a computer for the modern one...

[Dusty1]

He had 2 6.1's and put one in his '72 Cuda. Twin 4 barrels and old style valve covers looked awesome. He said there was a lot to it