[big hammer]

question... what was the actual hp output of a 71 455 ho?

[RATTCRUSHER455]

335 hp advertised pretty weak

[RATTCRUSHER455]

have a 71 formula 455 h/o milled heads down a bit and shoved a 041 cam into it that woke it up a bunch but still think they are over rated

[big hammer]

did the 71 455 ho have the 64 heads?

[RATTCRUSHER455]

negative round port 191/197 heads depends how you want to read them

they are 8 4 1 to one heads

the 64 heads are 1970 d port 10.25 to 1

[RATTCRUSHER455]

the biggest thing about 64 cast heads is drop the compression a bit

i am doing the same thing at a more grand scale, i have a 70 trans am real ram air iv car i have to drop the compression a huge amount via (ross reverse domed pistons)
614 heads on a 455 block is nose bleed compression ratio 11.5 at the very least

[RATTCRUSHER455]

the 1970 455 h/o was rated at in the gto at 370 hp and some say pontiac rated that same engine in the grand prix at 390 hp either way the motor made some serious power in the 70's and 80's people were after the 64 head and the 96 head and people were throwing away the 6x head i am not re writing history just stating the facts period dont get me wrong a 6x head does have its place today its just not on any of my bottom ends and one thing is for sure i have many heads on the shelf and i can use just about any casting i want for the street and 6x is not even a consideration but if i was broke and was on a budget and could not afford anything better then and only then i would use a 6x 4 as a cheaper alternative to a 64 or 96

[big hammer]

how many CC's do factory '75 pistons ad to the cumbustion chamber?

[455Grandville]

Originally Posted by RATTCRUSHER455

howdy brad

i am very sure if i was having detonation problems in any one of my 455 eingines with 64 heads it would have shown its ugly head by now 12- 15 years later and trust me i am not one of those afraid to stand on them.

my only trick will be to get a xf block to run hard with a set of 614's on the pump in my 70 t/a that we are frame uping

6X heads are far from junk; they do have hardened valves and seat, a bonus over the heads you speak of.

Maybe my build does not compare to yours: mine was for a highway car that I might drive several states, so I left some margin for error. Ive stopped at many gas stations in plenty of states that didn't have anything over 89 octane. and my car needs 93 octane.

The 455 H/O was 300 net hp which was not bad for 1972, considering all manufacturers had to drop their compression and lost alot of HP.

[big hammer]

Originally Posted by 455Grandville

6X heads are far from junk; they do have hardened valves and seat, a bonus over the heads you speak of.

Maybe my build does not compare to yours: mine was for a highway car that I might drive several states, so I left some margin for error. Ive stopped at many gas stations in plenty of states that didn't have anything over 89 octane. and my car needs 93 octane.

The 455 H/O was 300 net hp which was not bad for 1972, considering all manufacturers had to drop their compression and lost alot of HP.

that makes a big difference to how one plans their build. for what i'm doing i'll be lucky to run 3-4 tanks of gas through per year. if i can get the ratio at 10 or less i'm comfortable with that.

[big hammer]

what are the specs of a ram air 4 cam?

[RATTCRUSHER455]

brad a junk head is all that you compare it to, yes if you compare the 6x to a 6h, 11 47,45,17.7m1, 7m5 ,and heads in that realm yes a 6x looks like a porn star put it next to a 96 or a 64 it looks like a flat chested pole dancer

lets see
the 6x heads ranges in cc's like mitt romney does on political issues
the 96 heads where a little more consistant 96 cc's
the 64 heads where a little more consistant 87 cc's
the 6x head has screwed in studs, so does the 96 and the 64
the 6x head has all the 6 bolt holes for headers so does the 96 and the 64
the 6x head has harden seats so does the 96 and but 64 does not ( just put them in)
the 6x has factory guide plates so does the 96 and so does the the 64
ther 6x has a 211 intake valve and so does the 96 aand the 64
the 6x has a 1.66 exhaust valve
the 96 head has a 1.77 valve
the 64 head has a 1.77 valve

and as far as harden valves are concerned its a none player who in there right mind runs 40 year old original valves

so tell me why would i want to run 6x heads again ??????

like i stated before i dont have to go out and look for heads i have many on the shelf already i sell them world wide and sell what ever my customer wants but when it comes down to my 455 engines a 4x 6x 5c head is nothing more that a wheel chock, or a item used ot hold tarps from blowing off my future project cars.. but dont get me wrong every time i sell a set of 6x i really feel like i dodged a bullet because 125.00 a pair is far better than $10.50 per 100lbs for scrap

[2manyT/A'S]

The pistons in Pontiac V8's DO NOT affect combustion chamber volume unless you want to spend some extra $$$ for custom built ones.

You will find 6X heads to be the 1st choice on the MAJORITY of serious Pontiac 455 engines unless they have stepped up the aluminum heads.

Talk to ANY of the SERIOUS Pontiac engine builders out there & they will AGREE.

Ram Air IV cam is NOT a happy cam on the street.

It wants a MINIMUM of 3.90 gears,doesn't idle well & makes NO bottom end power.

The 455 HO cam is very happy on the street,makes TONS of bottom end power & can actually suppoert an A/C compressor at idle.

[big hammer]

Originally Posted by 2manyT/A'S

The pistons in Pontiac V8's DO NOT affect combustion chamber volume unless you want to spend some extra $$$ for custom built ones.
.

how does that work? if there are factory valve reliefs on the piston it certainly does add to the combustion chamber volume. i just wanted to know what the +cc's of the piston are so i can calculate my own compression ratio regardless of what heads i go with.

my car already has 4:11 gears, and a ram air 4 cam will be more street friendly in a 455 as opposed to a 400.

does anyone have the actual specs on a ram air 4 cam and a 455 ho cam?

[Lloyd-TX]

RATTCRUSHER - you, "sir", need to study up on some REAL facts concerning Pontiac engines and history. Your opinions are SCREWED UP!

'71 and '72 455HO engines are far from weak, in FACT some of the best engines Pontiac ever installed in their performance cars.

Get your facts straight, or go away!

[Lloyd-TX]

Originally Posted by big hammer

does anyone have the actual specs on a ram air 4 cam and a 455 ho cam?

http://www.wallaceracing.com/camcode1.htm

Besides thie above linked camshaft chart, John Wallace's website contains a BUNCH of useful Pontiac engine info, poke around a bit.

[RATTCRUSHER455]

the real reason most machine shops use 6x heads over 96 is based on availabilty the 6x head was used on everything so there are many out there the 96 and its cousin the 7k3 was 71 and 72 only as the 64 head 70 only. and that directly affects the price of a core

i provide a well known pontiac machine shop down here in the south with most of its 6x cores i know. for 150.00 a pair when he calls for a pair of 96 or 64 it becomes a case if you have to ask you cant afford it

and most of the time he replaces the 1.66 valve and installs 1.77 's to let them breath so you buy the heads for nothing and pay the machinist to fix the factory screw up and hope they do it right,,, what a deal, 96 heads never looked so good now do they

also a ram air iv in a 455 h/o with rhoads lifters works just fine on the street with a/c with a 373 gear, my biggest fear is the motor still pulls higher than the factory bottom end can handle

[RATTCRUSHER455]

lets see here i have a 71 formula 455 h/o have had it since 1987 i sold my 72 formula 455 h/o years back and i have a 74 formula with a 72 455 h/o in it right now 335 hp is soft..... stop reading hpp magaizine and all the hype, dont get me wrong glad i have them but totaly impressed by there power no hardly

[Lloyd-TX]

Originally Posted by RATTCRUSHER455

lets see here i have a 71 formula 455 h/o have had it since 1987 i sold my 72 formula 455 h/o years back and i have a 74 formula with a 72 455 h/o in it right now 335 hp is soft..... stop reading hpp magaizine and all the hype, dont get me wrong glad i have them but totaly impressed by there power no hardly

RC4, I don't just read, I do. But I do read, and study, and experiment. I've been building, tuning and racing Pontiacs since 1972, dude!

Not much gets me worked up, but calling the '71-'72 455HO engine weak and soft is quite simply - WRONG.

You OBVIOUSLY need to bone up on how to build, and more to the point - TUNE, your cars (that you supposedly own or have owned)!

[RATTCRUSHER455]

well better yet the on going joke over here for years is every time hpp does a article on a 455 h/o car they make the engines sound better than real life and all that does is make my 71 formula go higher and higher in value

out the box a wc bottom end with a set of factory 96 heads with a 71 cast iron intake and ram air manifolds will make more torque and hp than 197 heads with its whopping 111 cc heads and wayyyyyy cheaper 8.4 to 1 to 9.3 to 1

if i want the pat on the back wow thats rare i drive my 71 formula455 h/o

if i want damn thats pretty quick i drive my 77 trans am 455, 96 heads

my next trick will be the 70 trans am ram air iv car i want rare and quick and the donor 455 xf block with the 614 's should get that done for me my only hurdle is the pistons

let there be no mistake i know my pontiac history and own a bunch of it