73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: NevadaNeal on December 26, 2009, 02:10:11 am
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Ok guys,school me on the 396..I have finaly got my hands on one for my 73.
I have been researching mods and what not,but what i would like feed back from you on what to look out for and what to expect.
This engine is going into a shortbed 4x4 wich already has a built B&M T350.I have a T400 but still have not gone thru it.
Im not really building a fire breathing monster.I want healthy and stout.Any help will be great.
And the reason for the 396 and not a 454 is i have a 75 ford with a 390 and a 78 dodge with a 383..They are the Three Amigos.
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Need to know more info about your 396. What's inside? What heads are on it?
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This motor has been sitting for some time.the cork valve cover gaskets fell apart when i pulled the covers. the pan is baged up from being moved around and the oil residue on the inside is dry....but other wise a very stock and clean motor.
Head#3964292
block#3935440
If this motor has ever been rebuilt..it was over 20 years ago...ill pull the heads and check the bore.From what little i know about this motor...its changed hands about 10 times in the last 20 years but has never been in a vehicle in that time.
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3935440 1968-69 396 265, 325, 350, 375, 2&4 bolt
RECTANGULAR PORT - Valve size 2.19 intake, 1.88 exhaust
3964292 1970 454 Closed 450 LS-6, 109.0cc
I`d say look it over completly tear it apart and inspect it all.I would change the cam and crank bearings just because its been sitting all that time and could cause to get any rust.. Even though it is a rebuilt motor i still would tear it down and inspect everything..
Better to be safe then sorry..
thanks
pat
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Ill be paying close attention to this thread. I just got a 396 no.3916323. Says it out of a 68 chevelle which is perfect, because its going in a 68 El Camino
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I got a 68 396 as well under my bench i may just put aside and the new toy will get my 402... Look forward to pics and info..
thanks
pat
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If those are the rectangular port heads, they are for the high performance 396-454 engines and you may not get the torque you want at the bottom end.
There are basically 3 types of heads, truck ( peanut port ) heads which are the smallest oval port, the regular oval port heads, best for all around street use, and the rectangular port heads. ( There are other variations, but describing them is not important in this discussion )
The rectangular port heads were on the 375 HP 396, 425 -435 HP 427s, and I am not sure about 454s. They are a bit of a pain in the but for the street, but they are fantastic over 5000 rpm. I used a set on my 396, but went back to the 350 HP oval port heads on my engine ( with a 280 Comp cam, 725 cfm Holley carb, and headers ) Much better for all around use.
I installed my 396 in my 55 Cameo in 1970, and I love the combo. I am going to install a 454 because this engine belongs in a 67 Big Block Chevelle.
Bob
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thanks alot..i didnt know that. ;D
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There are many excellent books on the big block. I don't know if these are still in print, but you might check at your local high performance auto parts store.
HPBooks How to Rebuild Your Big Block Chevy By Tom Wilson
This book has some of the most common casting numbers and lots of excellent information
ISBN 1-884089-15-1
Part No. SA31
Car Tech Inc.,
Chevrolet Big Block Interchange Manual
By Ed Staffel Jr
They are an excellent read for anyone as crazy about big blocks as I am. I have a 366, 396, 427, and 3-454s
I need help
Bob
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Those heads might be valuable enough to fund the purchase of an aftermarket set of heads of a set of freshly rebuilt oval ports with nice parts, a valve job and maybe port-matching.
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If you are building for power and don't really plan to run the motor over 5000, Peanut ports will work, but they will taper off drastically around 4800-5000. Ovals are much better to around 6500ish, Rectangles are for all out high rpm power. I would probably sell them (or keep them) and find a set of ovals. If you need something fast, peanuts can be picked up for much less and complete. I have a rebuilt set that came off a rebuilt motor that I replaced with ovals.