picked up a 340 long block w/out specs

nixrsix said
I recently picked up a 69 340 long block from an auction. I couldn't get any info from the owner or even know who he/she is. All that was stated was a "69 Mopar 340 high performance 400hp supercharged race engine". It has roller rockers, electric water pump, and has the lower blower manifold(looks like it was never ran). I know the stock CR for these engines are 10.5:1. Should I just go ahead and throw on a 671/871 blower assuming the compression ratio is built accordingly, throw a regular intake manifold on it and run it without boost and enjoy it for it is?, or go through the hassle of pulling heads and calculating compression ratio? I'm guessing the correct route is the longest one and pull it all apart and check it all out myself, but just seeing what you folks think...

TIA
-N

Pull the heads and calculate the compression ratio. You have no idea who built it, what parts were used, or what the engine is capable of. The stock specs mean absolutely nothing if the pistons and heads aren't stock. You don't have to tear it down to parts, but if you pull the heads and pan you can inspect what you've got so you know how to proceed with any additional modifications.

Krooser said
If I were to buy a car would I disassemble the engine just to see what's inside?

Hell no....

Sometimes we get so anal about this stuff...we really do.

In the oval track world few, if any, guys buy a motor and pull it apart. We buy the stuff to race... Most give it a once over, check the valves, might swap a carburetor and put the thing on the track.

GM crate engines are like that (you mostly know what your buying) but is true with "open" motors, too. Might give a guy some smiles if he knowsw the engine builder was but means very little in the grand scheme. Either it runs or it doesn't.

I got over all that hand wringing over small details long ago.

Just trying to make your lives a bit easier...

This isn't a crate engine with published specs, they don't make crate engine 340's. Sure, not every engine needs to be fully blueprinted to have fun with. But this is a completely unknown engine. Built by an unknown builder, with unknown parts and only a description of it being a "400 hp supercharged race engine". Well, a 400 hp supercharged small block is super mild. That description doesn't even sound right to me. It could be ANYTHING in there. Toss it in the car and fire it up and you could wipe out a brand new engine in no time flat.