Stock oval port heads - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tomsC10R · 01-20-2004, 01:06 PM

It's a 396. What kind of performance manifolds will work with the stock oval ports cylinder heads? I have no experience with big blocks but read that the stock oval port heads are much different than performance oval port heads which would probably mean they're much different than the intakes that are matched to the performance heads. Please tell me I don't have to buy new cylinder heads too. Oh yeah, I just bought a Holley MPFI (not brand new)

Thanks in advance!!

JimKshortstep4x4 · 01-20-2004, 02:17 PM

To my knowledge, the oval ports were the same until you got into the newer big blocks where they had very small ports. If your 396 is 72 back, I believe that you will be ok with any of the performance manifolds. (The differences of course would be between oval and rectangular ports).

jim

tomsC10R · 01-21-2004, 03:03 AM

Thanks Jim.

Does everyone else agree?

Thanks again.

Pont · 01-21-2004, 04:06 AM

Yep, Jim is right on the money. I also have a 396 with closed-chamber oval port heads on it. Any performance manifold designed for oval port heads should work just fine (assuming it's not a tall deck 396 or 427).

tomsC10R · 01-21-2004, 11:23 AM

Thanks Pont,
That leads me to another question. Is there any easy way to tell if it's a tall deck? You can't tell just by looking can you? Are there certain casting numbers I should look for?

Thanks for all the help

superchevy · 01-21-2004, 12:06 PM

Check this link for big block casting numbers:

http://www.mortec.com/bbc.htm

zyggy72 · 01-21-2004, 12:07 PM

There are certain casting numbers for tall deck blocks. The deck height of a std block is around 9.5 inches from center of the crankshaft to the deck and a tall deck block is about 10.2 inches from the center of the crankshaft to the deck.
Hope that helps.

tomsC10R · 01-21-2004, 12:51 PM

Superchevy,
Thanks for the link!!

Just curious, but I didn't see any 396T (tall decks) listed on their page.

Not that I want it to be one

01-20-2004, 01:06 PM	#1
tomsC10R Registered User Join Date: Nov 2003 Location: Wisconsin Posts: 281	Stock oval port heads It's a 396. What kind of performance manifolds will work with the stock oval ports cylinder heads? I have no experience with big blocks but read that the stock oval port heads are much different than performance oval port heads which would probably mean they're much different than the intakes that are matched to the performance heads. Please tell me I don't have to buy new cylinder heads too. Oh yeah, I just bought a Holley MPFI (not brand new) Thanks in advance!! __________________ Tom 1968 C10 LWB. 402 BB, Holley MPI, 700R4. 4wheel Hydroboost Disk Brakes.

01-21-2004, 03:03 AM	#3
tomsC10R Registered User Join Date: Nov 2003 Location: Wisconsin Posts: 281	Thanks Jim. Does everyone else agree? Thanks again. __________________ Tom 1968 C10 LWB. 402 BB, Holley MPI, 700R4. 4wheel Hydroboost Disk Brakes.

01-21-2004, 04:06 AM	#4
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	Yep, Jim is right on the money. I also have a 396 with closed-chamber oval port heads on it. Any performance manifold designed for oval port heads should work just fine (assuming it's not a tall deck 396 or 427). __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"

01-21-2004, 11:23 AM	#5
tomsC10R Registered User Join Date: Nov 2003 Location: Wisconsin Posts: 281	Thanks Pont, That leads me to another question. Is there any easy way to tell if it's a tall deck? You can't tell just by looking can you? Are there certain casting numbers I should look for? Thanks for all the help __________________ Tom 1968 C10 LWB. 402 BB, Holley MPI, 700R4. 4wheel Hydroboost Disk Brakes.

01-21-2004, 12:51 PM	#8
tomsC10R Registered User Join Date: Nov 2003 Location: Wisconsin Posts: 281	Superchevy, Thanks for the link!! Just curious, but I didn't see any 396T (tall decks) listed on their page. Not that I want it to be one __________________ Tom 1968 C10 LWB. 402 BB, Holley MPI, 700R4. 4wheel Hydroboost Disk Brakes.

01-20-2004, 02:17 PM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	To my knowledge, the oval ports were the same until you got into the newer big blocks where they had very small ports. If your 396 is 72 back, I believe that you will be ok with any of the performance manifolds. (The differences of course would be between oval and rectangular ports). jim

01-21-2004, 12:06 PM	#6
superchevy Got big-block? Join Date: Jul 2000 Location: Austin, Texas Posts: 2,453	Check this link for big block casting numbers: http://www.mortec.com/bbc.htm

01-21-2004, 12:07 PM	#7
zyggy72 Can't kick the addiction! Join Date: Jan 2002 Location: Riverton, CT 06065 Posts: 402	There are certain casting numbers for tall deck blocks. The deck height of a std block is around 9.5 inches from center of the crankshaft to the deck and a tall deck block is about 10.2 inches from the center of the crankshaft to the deck. Hope that helps.



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