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Question for you BBC guys

tiger9297

tiger9297

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I have an opportunity to buy a BBC from a friend of mine who owns his own shop (468ci). He told me he has numerous BBC heads and I can basically pick the ones I want. I was planning on getting the casting numbers of the heads so I can see exactly what I'm getting. Do any of you have a link to a site where I can enter the casting numbers and get the specs. on the head? Ideas??

Also, I would like to put a serpentine setup on this engine (it' would go in my '90 K5). I see these kits for SBC's but not for BBC's. I have all the accessories I just need the brackets. Should I just go to the dealership and buy the individual brackets for an early 90's 454?
 
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I dont think there are kits offered for a bbc, you'll probably have to look in a salvage yard for something in the mid 90's.

As for heads I think most people will agree that the best heads to use will have casting numbers ending in "781" or "049". These are nearly identical so either would work great.
 
nvrenuf said:
As for heads I think most people will agree that the best heads to use will have casting numbers ending in "781" or "049". These are nearly identical so either would work great.
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781's are the best head of choice. The only thing that will make them better is to install the larger valves so they will breathe better and have slightly more flow. :thumb:
 
4X4HIGH said:
781's are the best head of choice. The only thing that will make them better is to install the larger valves so they will breathe better and have slightly more flow. :thumb:
Click to expand...

How would these heads compare to the L29 Vortecs?
 
Edit: Few more questions

Is a 496 just a 454 w/ a 4.37" stroke? Do you have to machine the block for clearance like you would when building a 383?

Is it worth buying aftermarket heads for a BBC or just stick w/ stock? They are $$$$$$$$$!!!

Is 8.5:1 CR high for a BBC. Seems like most "built" SBC's that run on pump gas are low 9's. Maybe its just the ones I've seen but seems like most BBC's are mid 8's?

Which would you rather have:

MPFI 383 w/ Vortec heads

or

MPFI 454 w/ stock heads and a cam?
 
tiger9297 said:
Edit: Few more questions

Is a 496 just a 454 w/ a 4.37" stroke? Do you have to machine the block for clearance like you would when building a 383?
Click to expand...

A 496 is a bored & stroked 454. I don't know if you have to machine the block tho. I will find out if mine was since you got me curious now.
 
Traditionally a 496cid is your 454 bored +0.060" (4.310") and crank stroked +0.250" (4.250")

I'll take a 454 over a 383 for a fullsize truck everytime.

tiger9297 said:
Edit: Few more questions

Is a 496 just a 454 w/ a 4.37" stroke? Do you have to machine the block for clearance like you would when building a 383?

Is it worth buying aftermarket heads for a BBC or just stick w/ stock? They are $$$$$$$$$!!!

Is 8.5:1 CR high for a BBC. Seems like most "built" SBC's that run on pump gas are low 9's. Maybe its just the ones I've seen but seems like most BBC's are mid 8's?

Which would you rather have:

MPFI 383 w/ Vortec heads

or

MPFI 454 w/ stock heads and a cam?
Click to expand...
 
Ill concur with everything on here, I have 049 heads, put in some 2.19/1.88 valves, and did a little porting, mainly just gaskey matching.

And yes a 496 is .030 overbore and .25" stroke.....:D​
 
k20 said:
Ill concur with everything on here, I have 049 heads, put in some 2.19/1.88 valves, and did a little porting, mainly just gaskey matching.​



And yes a 496 is .030 overbore and .25" stroke.....:D
​
Click to expand...


I guess I'm a little confused. I dig a little digging this afternoon and this site http://www.mortec.com/borstrok.htm shows the 454 and 496 to have the same bore but different stroke lengths. That is, if I'm reading this right.​
 
A 496 is a 454 bored .060" with a 4.25" stroke crank.

The formula for figuring out engine displacement is:

Bore x Bore x Stroke x .7854 x number of cylinders.
 
or V8 specific is
bore x bore x stroke x 6.2832


and the 496 listed on Mortec there is the late '90s Vortec 8100 engine. Yes works out to 496cid, but is not the same engine as stroking a carbed 454 to 496.
 
DEMON44 said:
and the 496 listed on Mortec there is the late '90s Vortec 8100 engine. Yes works out to 496cid, but is not the same engine as stroking a carbed 454 to 496.
Click to expand...

That is correct.
 
so..do you have to machine the 454 block to have enough clearance for the 4.25" stroke crank?

Will the accessories- a/c compressor, alternator, water pump, p/s pump off of my 350 work w/ a BBC if I get the BBC brackets?
 
Some of em you will have to barely grind, some you wont have to at all, and some you will have to grind a fair bit. Mine didnt need any.

Water pump wont work, p/s pump may or may not, depending on the brackets you get and the style of pump you have now. Same with the A/C compressor. The alternator will work.

Also keep in mind you will need either a 4 core, or an aluminum radiator to keep up with the big block.
 
tiger9297 said:
so..do you have to machine the 454 block to have enough clearance for the 4.25" stroke crank?
Click to expand...

Yes, you will have to chamfer the edges so the piston rods will clear the bottom of the cylinder.
 
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