Hot Rod Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
I came across an engine with casting number 3970010. I have tried to figure out what this engine is from, (I know is is a 2 bolt main from pulling the pan and looking) and am wondering how much juice I can expect from it with a simple rebuild job. I am a newbie. I have been unable to find any partial vin numbers or engine codes on the block. I checked the tab in front of the pass side head and it is completely smooth/blank. Can anyone help me identify this thing? Where else should I be looking for identification numbers/codes? This engine is a complete mystery to me - got it for free from a non-car buff friend who inherited it with a house.


For me this will be my first engine rebuild. Any wisdom will be much appreciated!!!!
 

·
Registered
Joined
·
12,338 Posts
probably a 350,could be a 327,lates 60s early 70s. Power is decided by the combination of parts. stock output was likely 250-300 hp
 

·
Registered
Joined
·
3 Posts
Discussion Starter #3
further info

There are a couple of pics of the numbers I have found in my gallery. Again, any and all help appreciated.
 

·
Registered
Joined
·
2,643 Posts
Casting number 3970010 was used on both 327 and 350, so it does not tell you anything directly.

As part of your rebuild I assume you plan to pull the heads, so this is the time to measure the bore size and stroke. That will answer your initial question about displacement.

There are many moderate builds in the 250-300 hp range that only swap cam, intake and carburetor. The next step up is usually a head swap, which can get you another 40 hp.

The heads on these engines are a significant limitation on adding horsepower. They work fine for standard performance, but the flow is not that great. Swapping to GM Vortec heads or aftermarket aluminum heads will help a lot, but its a big chunk of money compared to just swapping carburetors and manifolds. The flat tappet cam is also less flexible than a roller cam would be for more aggressive profiles.

Your engine build should be matched to the vehicle and how you plan to use the engine. If you try to hit 400-450 horsepower with a 350ci engine you will only get that horsepower at relatively high rpm. This usually means you need a high stall torque converter to get the rpm up, and that it works best in a light vehicle that doesn't need a lot of low end torque to get off the line.

Bruce
 

·
Registered
Joined
·
527 Posts
3970010 may be the most common block used from '69 through the seventies, two- and four-bolt main. You might have to look really hard and do some cleaning to read that number on the pass-side front deck, then the codes can be found on the 'net. Nothing wrong with it, but check the bore...if it's already been overbored you may ask around for opinions on boring it further. As said, heads will be nothing special, if you were to use them at-least check that they are unleaded-gas compatable but newer designs will be more efficient and less prone to knock, after the rebuild expense involved it is almost not worth it to use old ones such as the also-common -882. Other guys here can tell you more than I in any event...
 
1 - 5 of 5 Posts
Top