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View Full Version : Pontiac Ram Air IV, 455 H/O question


Ummgawa
02-10-2006, 12:43 PM
I need some clarification. I have been looking for a set of 455 H/O heads. I assumed they were Round port heads like the RAIV heads. I founds a set and asked the guy a lot of questions and the last question was if they are round port heads. He said no that the 455 H/O came with D port heads and no Ram Air exaust manifolds,just log type. Well, that was a surprise to me. I thought he was BSin me to sell me some heads but now, on the wicked Judge Vert thread on the Ebay ad at the bottom, there is a simular question and this guy asks:

Q: Awesome car, way out of my league. Have casually known owner of 1 of the other 455 Judge converts, bought from supposed original owner in 75. Believes the driveline was untouched. The thing is, his car had HO exhaust manifolds on it. He has the Build Sheet, original window sticker, etc. although he has been unwilling to share them. His was also built fairly early, has YA code motor so built before the switch to the YC code around MUN 210000. Anyway, I'm interested in knowing if your car has HO or regular log manifolds. I'm also be interested in knowing what the Build Sheet says at the bottom. So very few of these cars were built, it is difficult to learn much about them. There is much confusion about the availability of the 455 in the Judge. Base Judge was RAIII but the Ram Air was a separate option for the 455, it isn't clear if the Ram Air was automatically included with the 455 Judge package. Same for the HO exh manifolds, could they have been included too?
Feb-09-06

A: HI MY JUDGE DOES NOT HAVE RAM AIR EXHAUST MANIFOLDS. I DONT THINK ANY OF THE RAM AIR 455 IN 70 HAD THEM.I HAVE A 70 455HO RAM AIR CONVERTIBLE ALL ORIN IT ALSO DOES NOT HAVE RAM AIR MANIFOLDS. BUT IT DOES HAVE ON THE BUILD SHEET THE EXTRA CHARGE FOR THE 455 AND THE RAM AIR OPTION. IT CAME WITH A RAMIV CARB.FROM THE FACTORY NICE TO TALK TO YA. GARY


Charley, Bill, Jonny or any of the many Pontiac Guys, any heads up here?

jonny51
02-10-2006, 01:22 PM
Jim I am pretty sure the RA IV,HO and SD heads are all round port.The SD's were worked for more airflow or something like that :_paranoid

andrewb70
02-10-2006, 01:34 PM
I belive that in 1970, the 455HOs had D-port heads.

Andrew

jonny51
02-10-2006, 01:41 PM
After looking around I think you are right Andrew.

Smack_talker
02-10-2006, 01:42 PM
H.O. and SD heads are D-ports, I think. I know SD heads are D-port not positve on HO. Do you have the casting number? That would tell you what it came on.

Ummgawa
02-10-2006, 02:06 PM
I have seen a SD 455 motor with Round port heads. The D ports on the 455 H/0 surprises me, though. Thanks for all the help and knowledge. I went to a few Pontiac sites and no help there either. A few "let me get back to you on that" replies.

Ummgawa
02-10-2006, 02:13 PM
MORE CONFUSION!!

See this article on the 455HO and the Super Duty:

http://www.highperformancepontiac.com/tech/pon_0505_sd/

Down where the picture of the 455 SD head is-

The round-port SD-455 cylinder heads were similar to those found on the R/A-IV and 455 H.O. engines but with revised intake and exhaust ports for even greater flow.

andrewb70
02-10-2006, 08:32 PM
Did you make a post on

http://www.performanceyears.com ?

I bet someone there iwll know for sure.

Andrew

bob johnson
02-10-2006, 09:09 PM
Did you make a post on

http://www.performanceyears.com ?

I bet someone there iwll know for sure.

Andrew

Call Jerry Burge at Ga Hot Rods..he will know..he's a Pontiac specialist.
770-734-9829

jonny51
02-10-2006, 09:19 PM
I got this off of another site...


The1970 455 HO had D port heads, 4 bolt mains, cast iron intake, factory cast headers, nodular crankshaft, 60 PSI oil pump, for 1971 the 455 HO had the aluminum intake, round port heads, cast iron headers, 4 bolt mains, nodular crankshaft, 60 PSI oil pump.

Kendall Burleson
02-10-2006, 09:20 PM
T&P machine shop in San Antonio,Texas ask for Barney Moravits he being racing the SD in nhra stock elem for 30 year.(210) 224-0886 :yes:

clill
02-10-2006, 10:33 PM
My 73 SD has round exhaust ports with the manifolds held on by 3 bolts. The ports ar so big they have steel sleeves cast in for the pushrods to go thru. The sides of the tubes are exposed in the exhaust ports. My 70 SJ Grand Prix had a 455HO but it did not have the round port heads.

ProdigyCustoms
02-11-2006, 02:13 AM
I just sold a set of dated correct 71 HO heads from Kevins (Jagarang) Firebird motor. I still have the manifolds and they are round port.

jonny51
02-11-2006, 02:23 AM
I just sold a set of dated correct 71 HO heads from Kevins (Jagarang) Firebird motor. I still have the manifolds and they are round port.

I think they switched to 0 port in 71 on the 455HO.

Ummgawa
02-11-2006, 07:27 AM
It is clear that Pontiac did not want the 455 HO upstaging the Ram Air IV. Seems the 4 had all the goodies. Imagine the 455 HO with the 2 piece aluminum intake and the round port heads/with RA exaust manifolds. No substitute for cubic inches, unless, of course, you twin turbocharge it.

Anybody here have any idea on the true HP numbers on a 455 HO or a RAIV, not what was posted by GM to get Muncie or turbo-hydro to guarantee the transmissions behind the motors?

ZMAN1969
02-15-2006, 01:25 PM
68 RAII - round port
69 RAIV -round port
70 RAIV -round port
70 455 ho- d port
71,72 455ho round port
73,74 super duty - round port
71-74 had big combustion chambers
68,9,70 RA had 72cc chambers
thats all i know :willy:

Ummgawa
02-15-2006, 04:34 PM
Thats a big help!

Thanks :yes: