Hot Rod Forum : Hotrodders Bulletin Board

Hot Rod Forum : Hotrodders Bulletin Board (http://www.hotrodders.com/forum/)
-   Engine (http://www.hotrodders.com/forum/engine/)
-   -   8.1L 496 vortec big block chevy, what is it? (http://www.hotrodders.com/forum/8-1l-496-vortec-big-block-chevy-what-44648.html)

406 ss monte 08-01-2004 12:52 PM

8.1L 496 vortec big block chevy, what is it?
 
i found a 496 bbc. i've never heard of it before. is it the same as the 454's & any other big block chevy? do the bolt up like the older ones? do they use the same heads, intake, & other bolt on's? are they a good choice for a build up? like i said, i've never heard of them. i know about the 454 stroker 496, but this is a factory short block. thanks for your help.

BOBCRMAN@aol.com 08-01-2004 01:40 PM

It is a factory, heavy truck motor. Cast iron crank. Strictly a low rpm workhorse. It is based in the latest series of big blocks, with their cooling and oiling differences, one piece rear main seal. As built, there is nothing hi-performance about it. Heads are small port truck.. But, those glorious cubic inches! Add some hot rod parts and you should have a real stump puller..

406 ss monte 08-01-2004 01:46 PM

will the older heads & intake bolt to the new block? do any of the 496's come with steel cranks? it's a lot of motor, but if the older stuff wont bolt to it, i can't use it.

BOBCRMAN@aol.com 08-01-2004 08:44 PM

I am told that none of the older stuff will work. 502 heads will work. Cranks are all cast, and use one piece seal type flywheel.

I accidently acquired one for the shop this spring from a local truck repair shop for $75.00 (core engine). They thought it was a 502, as it uses all the same external parts. This one had a noise, that turned out to be a spun rod. The rods are longer than a stock big block. I believe they were +.400 stock. We ground the crank and resized the rod. Freshened the rings and bearings and sold it to some very lucky person on Ebay. I would have liked to keep it..

406 ss monte 08-01-2004 09:36 PM

aren't the 502, & 396,427,454 heads all the same as fare as the bolt pattern on the deck surface? if they are, why wouldn't the older heads, intakes, & distributors work?

Miket 08-01-2004 10:54 PM

I have one in my Suburban---345 hp and 460/470 lb-ft torque. They have distributorless ignition....so a manifold swap would be in order---I "thought" these were an all together different block than the newer mark 5 big blocks----could be wrong. With a good computer tweak and a cold air intake guys have seen 50-75 hp gain at the rear wheels on a dyno.

deuce_454 08-02-2004 03:50 AM

Quote:

aren't the 502, & 396,427,454 heads all the same as fare as the bolt pattern on the deck surface? if they are, why wouldn't the older heads, intakes, & distributors work?
actually they are not the same.. the waterpassages are diferent, if you try and bolt a mark 5 head to a mark 4 block the water will pour into the oil.. and if the new vortech 8.1 is reverse cooling nothing will work.. it would be like bolting a set of camelhumps on an lt4. it might bolt up, but cooling would be non existent...

but with some tall reared gears i think it would be a killer engine, and if you can have it cheap.. have at it..

BOBCRMAN@aol.com 08-02-2004 09:01 AM

Correct. The water passages are different and the oiling is different. They do use a coil pak but the block is still for a distrib. The intake is impressive looking with the black and aluminum theme carried over from the cast valve covers.

406 ss monte 08-02-2004 12:00 PM

all there is is the short block, so if the older "good" heads wont work, i can't use it. i'm sure the heads & they use anen't worth a dime for 600 horse power like i'm wanting.

how can you tell the differance from all the blocks to know what it is? like the differance in a mark 4 & a mark 5 block?

deuce_454 08-02-2004 01:35 PM

the best way to check engine type is to look up your castingnumber. im betting yours is a 12556110. its a 01 up 4-bolt, Gen.VII 8.1L, "Vortec 8100", Truck engine

im not sure if you can get performance heads for a gen 7. but mercruicer just came out with a performance big block based on that engine that put out about 425 Hp with gen 7 heads, 9:1 comp and a 5000 rpm marine cam, so dont dispare

Super Streeter 08-07-2004 07:02 PM

There is limited swapability between the 8100 and most other bigblocks.The shortblock is a gen 6 type lowdeck with a 4.25" bore and 4.375" crank and stock length heavy duty rods.The crank is nodular iron with winged counterweights and is a good performance piece.I assembled a 555 using the crank from a 8100 vortec in a later 502 block{.030" over} and with lightweight pistons and steel 4.385" rods it lives fine making 850 hp at 7000rpm.We had some of the prototype stuff when it first came out and GM's intentions were to build a 496 inch shortblock that used standard bigblock valve angles and valvetrain components but had symetrical port prostock style heads ib it.The early version that I worked on had a 10 bolt head pattern like a ford motor but it used massive 5/8" studs.The intake used 4 bolt per side composite plastic intake.The heads flow very well and with a little bowl blending and some 2.25" intake valves they will outflow even the best aftermarket standard bigblock heads,and the cross section is small enough to make it all very streetable.Like I saud,the heads are very prostock like.I never worked with an entire production engine,but I know that the production piece uses a standard bigblock head bolt pattern and gen 6 water passages,and will use at leas regular mark 4 rocker arms if the studs are correct.It would be a great performance piece,and when I first got it I was working on building a combination to run my rae car in a class that requires production part number car or truck casting engine blocks and heads,with displacemnt limited to whatever you could stuf in a stock block,and since the original prototype was a siamsed wall casting,I was looking into it as the ultimate loophole combination once the engine went into production.The rulemakers required carbs and a regular distributor and sheet metal intakes or distributorless coversions were illegal,so the engine lost it's potential.All in all,if you dont mind working with the efi,the longblock has lots of potential for a drag race or stret rod buildup.Good luck.

68c10owner 08-08-2004 12:01 PM

there is a post at ls1tech.com about performance heads and a intake for the 8.1 motor. the parts were expencive but they were aluminum and would make alot of power.

GoneNova/406 08-08-2004 12:24 PM

if you would jump over to mortec.com,i think you can look at their bore and stroke list for big block chev's and find out that a 496 is a stroked 454=4.250x4......496=4.250x4.37....i'd almost rather have one of these than a 502which is 4.66x4

deuce_454 08-08-2004 03:02 PM

4.5x4, id say that getting the 496 shortblock and installing the rotating assembly in a bored 502 block with some aftermarket gen 6 heads, pro topline 320 or dart 360 allong with a rollercam is your best ticket.. a healthy mechanical-rollercammed well breathing 555 bigblock should be good for 750 Hp on pump gas with mufflers

Duke of Cruel 08-26-2006 04:19 PM

Quote:

Originally Posted by 406 ss monte
i found a 496 bbc. i've never heard of it before. is it the same as the 454's & any other big block chevy? do the bolt up like the older ones? do they use the same heads, intake, & other bolt on's? are they a good choice for a build up? like i said, i've never heard of them. i know about the 454 stroker 496, but this is a factory short block. thanks for your help.


its an vortec big block , same as the truck engines and in family with ls1/ls6 etc.
DoC


All times are GMT -6. The time now is 08:29 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.