6272292 BBC heads mystery - Chevelle Tech
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  #1  
Old Jan 19th, 06, 12:52 AM
blue66 blue66 is offline
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Brian Gooding
 
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Default 6272292 BBC heads mystery

Anybody have some real info on these heads, I know they are open chamber.
They also have a large area of material missing behind the exhaust valve opposite of the spark plug. Will this help flow or no benefit. Anybody ever flow tested. just curious. i have a set that have 2.25 I, and 1.88e valves and have been ported quite a bit, they seemed to work well but have no idea what they are capable of. I will get them flow tested and find out, but if anybody has any info it would be appreciated. Thanks, Brian
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66 Chevelle SS
496ci, Pump gas, no dominator, no spool, no electric fuel pump, no electric water pump, no big tires, full interior. N/A.
1.37
6.21 @ 109.7
9.82 @ 134.9

9.87 pass/grudge match http://youtu.be/Au6Lq7rH9Ak

"Keep your hopes up and your pedal down"....Rowdy
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  #2  
Old Jan 19th, 06, 7:44 AM
GOSFAST GOSFAST is offline
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Default Re: 6272292 BBC heads mystery

Quote:
Originally Posted by blue66
Anybody have some real info on these heads, I know they are open chamber.
They also have a large area of material missing behind the exhaust valve opposite of the spark plug. Will this help flow or no benefit. Anybody ever flow tested. just curious. i have a set that have 2.25 I, and 1.88e valves and have been ported quite a bit, they seemed to work well but have no idea what they are capable of. I will get them flow tested and find out, but if anybody has any info it would be appreciated. Thanks, Brian
Hi Brian, these are the identical heads used on the LS-5 BB from the Chevelle and the Corvette. The part number on these heads is 3999241. Different number, similar casting. The same casting was also used on the 402's in the Chevelle's. On the LS-5 we recently delivered with a 9:1 C.R. we made 410 HP and 485 Ft.Lbs. but with a 4.250" stroker. Hyd. roller retro and runung 15 inches vacuum. It was built for a 100% restoration. Used stock cast iron intake, Q-jet, and stock exh. manifolds. The heads work OK for their application. Thanks, Gary in N.Y.
P.S. I do believe that number,6272292, was specific to the 402 only.
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  #3  
Old Jan 19th, 06, 1:48 PM
Harold Sutton Harold Sutton is offline
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Default Re: 6272292 BBC heads mystery

Quote:
Originally Posted by blue66
Anybody have some real info on these heads, I know they are open chamber.
They also have a large area of material missing behind the exhaust valve opposite of the spark plug. Will this help flow or no benefit. Anybody ever flow tested. just curious. i have a set that have 2.25 I, and 1.88e valves and have been ported quite a bit, they seemed to work well but have no idea what they are capable of. I will get them flow tested and find out, but if anybody has any info it would be appreciated. Thanks, Brian
My parts interchange manual says they are 70-78 oval ports with open chambers. I kinda doubt they would have come on a '70 though as G.M. changed over to low compression in '71 so maybe my book is a little off. They apparently have been worked over quite a bit as the stock valves would have been 2.06 and 1.72 in diameter. My son had a set of 781s that had been pocket ported and big valves (2.19-1.88) and they flowed nearly 300 CFM. The 2.25 valves may be too big and will require a large bore for maximum effectiveness.
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  #4  
Old Jan 19th, 06, 9:55 PM
pdq67 pdq67 is offline
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Paul
 
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Smile Re: 6272292 BBC heads mystery

BB heads that are squared off over by the exhaust valve to match the intake valve line are actually open chambered smog heads with almost no quench!

And as big as the chambers look, they may be as small as 112 to 113 cc's!!

I figure they are still darn good heads as long as you can create the compression you want.

Please cc them so you will actually know what size they are.

pdq67
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  #5  
Old Jan 20th, 06, 10:18 AM
Whittaker Whittaker is offline
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Rob
 
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Default Re: 6272292 BBC heads mystery

I have a set of these too and have looked for info on them, but have found very little. I wish more was known about them. Like would they flow like a 781 or 049?

That 496 above seems pretty tame.
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1966 Chevelle Malibu 489, 870 Holley, Edelbrock RPM Air Gap, 781 oval ports, TH 400 Gearvendors OD/UD, 12" disks up front and 9 inch with 3.50s.

1966 Chevelle wagon, 408 SB, 3.73 12 bolt, 700R4, 12" discs front 10" rear.
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  #6  
Old Jan 21st, 06, 1:30 AM
blue66 blue66 is offline
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Brian Gooding
 
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Default Re: 6272292 BBC heads mystery

Quote:
Originally Posted by pdq67
BB heads that are squared off over by the exhaust valve to match the intake valve line are actually open chambered smog heads with almost no quench!

And as big as the chambers look, they may be as small as 112 to 113 cc's!!

I figure they are still darn good heads as long as you can create the compression you want.

Please cc them so you will actually know what size they are.

pdq67

Well the chambers look huge even when sitting next to a set of stock 049's but I cc'd them and they come out to 110's. Hope they flow well. That will make a 10.9:1 496 with a 18cc SRP piston.
__________________
66 Chevelle SS
496ci, Pump gas, no dominator, no spool, no electric fuel pump, no electric water pump, no big tires, full interior. N/A.
1.37
6.21 @ 109.7
9.82 @ 134.9

9.87 pass/grudge match http://youtu.be/Au6Lq7rH9Ak

"Keep your hopes up and your pedal down"....Rowdy
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  #7  
Old Jan 21st, 06, 4:01 PM
Tony66 Tony66 is offline
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Default Re: 6272292 BBC heads mystery

I have the 6272292 heads on my 402.They were on this motor when I bought it as a virgin engine years ago.2 rebuilds later I have it in my 66.It's bored 60 over with KB pistons and XE 268 cam.Stock size stainless valves with mild porting.These heads work real well in this application.The heads cc'd at 111.(This engines actually for sale now as I have a 454 that Ive built going in the car.)The 454 has the same heads only their 241 castings.I had thme machined for 2.19-1.88 valves and mild porting.These heads cc'd at109 after being surfaced and I know that they were redone previously.I hope they work as well on my 454 as thy do on the 402.Just my opinion.Tony
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  #8  
Old Jan 21st, 06, 5:11 PM
pdq67 pdq67 is offline
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Paul
 
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Thumbs up Re: 6272292 BBC heads mystery

I have a real old mag. that did a rebuild of these heads b/c they wanted to just use what came on the motor!

After it was all said and done, they did pretty darn good for open chambered, smog heads if I recall right.

I also think in the article they used 30 degree seat angles to make them create better low to mid lift suck like the Pontiac heads do.

Good heads if the CR. comes out where you want it, imho..

pdq67
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  #9  
Old Jan 21st, 06, 7:43 PM
Whittaker Whittaker is offline
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Rob
 
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Default Re: 6272292 BBC heads mystery

SO they are like a semi-open chambered head. So if you pick the right pistons they could be a good head to use. I know mine dated like 1971 or 72.
__________________
1966 Chevelle Malibu 489, 870 Holley, Edelbrock RPM Air Gap, 781 oval ports, TH 400 Gearvendors OD/UD, 12" disks up front and 9 inch with 3.50s.

1966 Chevelle wagon, 408 SB, 3.73 12 bolt, 700R4, 12" discs front 10" rear.
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  #10  
Old Jan 21st, 06, 7:54 PM
pdq67 pdq67 is offline
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Paul
 
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Smile Re: 6272292 BBC heads mystery

No. They are like great big open chambered heads, but actually cc smaller!

They almost don't have any quench flat to them..

pdq67
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