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Just looking around marketplace I found a guy locally selling a couple 396 motors. Based on the description they appear to be original 396’s out of a Camaro or Nova etc.

39999290

3955272

Those are the block numbers. Just doing some research it looks like they may be a couple sought after motors. Mostly the 3955272? Anyone know any info?
 

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These are common late 60’s early 70’s heavy duty castings used in trucks and performance passenger cars with 4 bolt mains or in lower duty trucks like half ton two wheel drive and grocery getters with 2 bolt mains.

These are decent blocks to build on but are not anything unique as Rat blocks go.

Check the ID pad the codes there tell you how it as built and include a partial vehicle VIN.

Bogie
 

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In gross HP with a good heaping spoonful of marketing exaggeration, it was 425hp. By today's SAE net standards that equates to about 300 hp tops.
Install an engine in your vehicle avoiding power robbing accessories and automatic transmissions and using headers/free breathing exhaust system and air cleaner to avoid losing power to the installation...
Dyno of L78 396" engine:
 

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The BBC 366" is like finding the SBC 262"... LOL!
The 366 is probably closer in dimensional undesquare-ness to the crummy 267 SBC....tiny bore and relatively long stroke, with no bore diameter to accommodate bigger valves at all. LOL

i agree there is nothing special in today's performance market for any 396 block....the only persons actively looking for one are searching for a numbers matching resto deal for a muscle car....not top performance.
Another possible outlet for flipping used blocks might be NHRA Stock or Super Stock class builders....but that's a narrow market.
 

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But the OP said these are 396 not 366 and the casting numbers match that of 396 blocks not the taller 366T block. The one you really have to watch out for is the 427T as it is also the tall truck block that is not the same as the passenger car 427. Although the stroke and bore are common as are the rods, the pistons are significantly different pin position to the crown 427T at 2.16 inches the standard 427 has some variations thart run from 1.645 to 1.77 inches and ring count differences with the T engines having 4 rings the non T engines use the more conventional 3 ring config.

When you start playing with the older Rat motors you have to watch what you got pretty closely.

Bogie
 

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But the OP said these are 396 not 366 and the casting numbers match that of 396 blocks not the taller 366T block. The one you really have to watch out for is the 427T as it is also the tall truck block that is not the same as the passenger car 427. Although the stroke and bore are common as are the rods, the pistons are significantly different pin position to the crown 427T at 2.16 inches the standard 427 has some variations thart run from 1.645 to 1.77 inches and ring count differences with the T engines having 4 rings the non T engines use the more conventional 3 ring config.

When you start playing with the older Rat motors you have to watch what you got pretty closely.

Bogie
But its not near the interchange nightmare that is ford !
 

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re "OLD"?
You wouldn't enjoy a 425hp 396 ? I'd certainly take one ..

not at all really as my mouse would destroy it. If I build another rat I would go 540 as its the best power to dollar option
 

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Chevrolet Lied! Stone-Stock 1969 L78 396 Big-Block Makes 50 HP More Than Factory Rating
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Was totally surprised they reached 425 HP with the iron exhaust manifolds! And then 30 more with headers...
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Of course a SBC mouse motor with modern heads can make even more power with less cam duration and lower compression ratio:
.
 

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Chevy never really lied about their power ratings they just picked a lower RPM’s output to call max. The engine could be revved higher where it would produce more power as the cam and induction where they took the advertised reading would support more rev’s and rev’s is where the horsepower hides.

The 290 horse 302 was very happy to rev a thousand more RPMs in factory trim above its rated output.

Bogie
 

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We all do things for different reasons , some of us do it cause it makes us smile , some of us do things cause it feels good , some of us to remind us of our younger days . most of us don't care if its the " best , fastest , most powerful , better looking , some of us have learned that those things are , at best , short lived & at worst unattainable , a fools errand if you will . I don't really care if there are those who wish to try to obtain the impossible , it would be nice if those folks wouldn't feel it necessary to belittle those who don't , its not only obnoxious , but its condescending & unnecessary !
 

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You wouldn't enjoy a 425hp 396 ? I'd certainly take one ..
I was there in the day and the 425hp Corvette was the quickest thing you could buy in 1965, but it was unfortunately a short-fused grenade. I knew guys who blew them so many times the dealers refused to repair them under warranty. Once the word was out, some dealers refused to take orders for them; didn't want the grief.

jack vines
 
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