What would the compression be on a 1964 409 truck engine? I have read up some on these and it appears that there is a notch in the combustion chamber in the block. Did all truck blocks get the notch in the cylinder? My block has the same 3844422 casting number that a car block has. Would the pistons be different from a car engine to truck? The engine is out of an old fire truck with 11,000 miles. Ideally, I would like to re-seal the engine, add a bigger camshaft and put the engine in my '40 Chevy coupe. But if the engine has 7:1 compression or something like that it doesn't make a lot of sense to cam the engine up without making some changes to the pistons. Any knowledge on these things would be appreciated.
Your 409 Truck engine can be a solid base for a performance build. It is a low compression engine though, with truck engines being 7.75 compression. That's is not all that hard to change with a piston swap. however it is not always all that simple. You probably will also have to bore the engine at the time of the piston swap. remember a 409/348 block is a little of a different type animal. With its deck angle of 74 degrees as opposed to the more common 90 degrees not just any machine shop has the deck plate to bore a 409. That was a problem I had when rebuilding the 409 I had. Your plan to just reseal and add a bigger cam is not going to be that simple in all probability. Those old 409's are worth the trouble it's just not going to be fast and dirty.
A rebore at a "good" shop shouldn't be a problem. As you say, a deck plate for a GM, "W" engine might be all but impossible to find, but unless you are going high end racing, it's really not a big concern not to have / use one. Mike
Take a look at my 20 day build in my signature line. You can see what I did with a low milage 409 truck block.
Also, be aware Chevy used 348"s in trucks long after they were no longer used in cars. It requires an expert to differentiate between a '64 truck 348" from a '64 truck 409". We just went through this recently. jack vines
The engine in my 34 truck originated in a big Chevy dump truck. The heads have a small combustion chamber in them a opposed to none in a car engine. Some truck blocks have one notch, some have two. If its low mileage, you may be able to just hone and change pistons to up the compression. SHowcars.com is a good place to buy parts. The big trucks have a distributor that isn't good for a passenger car engine, you need to find one, and the water pump is probably one of those big honkin' water pumps that needs to be swapped also. By the time I finished building my engine, the only original engine parts I kept from the truck was the heads, rods, and oil pan because my truck block was cracked and I found a passenger car block to replace it.
I'm no expert but my block does have the 409 3844422 casting number and QE suffix code, which all point to it being a 1964 409. There is also an "X" cast into the drivers side front of the block. Is there something else that I am missing which could lead to it being a 348? Thanks to everyone for the replies. It sounds like I need to find some 425 horse pistons to bump the compression up some. Ideally, I'd like keep it standard bore and just hone it/drop in the 425 horse pistons if I go that route. I won't be putting a lot of miles on the engine, just cruising around town in my hot rod. But I want it to run strong and sound good. I'll just have to see how much it is worn when I tear into it I guess.
With a less than 8:1 compression ratio, this engine sounds like a perfect candidate for a blower to supply it with a bit of extra boost. Just so you don't try to "over-stuff" it too much. Though finding a blower manifold for a W block might be a challenge.
Pay no attention to the X. Mine had an X and it was a 348. The 348 truck uses the 409 oil pan too so you can''t go by that. You need to open it up to be sure.
this link to the 409 site talks of the X on the 64 block and further states it to be a passenger car block. I would pull a head and see if the cyl walls have the truck low compression notches cut in the side wall. Curious what the head number is. Have you looked under the valve cover yet? http://www.348-409.com/cgi-bin/block/csvsearch.pl?block=3844422 and a link to the head ID page http://www.348-409.com/headcast.html
That is interesting. I did look under a valve cover and it has the truck heads with the casting number that ends in "333." They also have the valve rotators under the exhaust valve. So, the heads are nothing special. I'll pull a head once I get it up on a motor stand and check for a notch. Not that I would know what a truck notch looks like compared to a car one. I'll post pictures when I do. Thanks everyone.
Like scotty t said go to 348-409 site. they have everything you would want to know and a forum to ask guys that live w motors every day! That's where i went for all the info i needed before i pulled the trigger on my 409 truck block.
John, here is a link to a thread regarding notches (small/large) as seen in the W engines. Has pics for reference http://www.348-409.com/forum/thread...-made-them-different-sizes.40850/#post-438009
If it is a 409 casting number, it is a 409. Truck motor will have 1 notch. Not a big deal as it unshroud the exhaust valve, and drops about .75 compression. Stock it makes 252 horse and I forget how much torque. If it runs good, run it! It won’t be a rocket, but will run good.
"Rotaters" under the springs ? That was special - for heavy duty use - Studebaker did it as well in the 50's....guess it was a common truck thing..... '
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