[RATTCRUSHER455]

yes you are right the fastest my 71 ever ran was 13.20 so yes maybe it needs a tune upor a good sesssion of power tuning my 77 t/a with a 455 yc station wagon 2 bolt block 96 heads with 373's run 12.60's with me pushing and pulling the muncie all the way down the track and your point is what ?????? 96 heads rebuildable cores 450.00 just sold a pair of 197's on ebay this morining for 25000.00 ummmm what is the better value here when it comews to go fast or go faster????? its ok to be proud of your 72 h/o i am proud of mine but its not all that but thanks for the referance maybe i can get that marshmallow of mine to squeeze some more power out of it

['ol Pinion head]

and if you had any sense, and your '70 T/A is a real RAIV car, it would be cashed out on so you could play with455's in whatever. Is that too harsh, not trying to offend ya. I don't get the '73 WW 455, the reverse dish Rosses, and the '70 614's, why not buy race gas & build the engine similar to B Mod prod 614 headed 455's of the 70's, I know several that were built and ran low 11's, that was with old technology heavy pistons, heavy SD rods, etc. Got to be able to do better today.

71 96 head 455 combo's are nothing new. The old DAPA bunch in Dallas were ate up with them in the early '90's. I sold nearly ra dozen pair of nice '71 96 cores down that way. Bought my 1st 64's in '82, built with them in '84. Since then, have bought & sold near a dozen sets, theyre nothing special. I have one set of I 69date #64's tucked away if i ever was so ignorant as to blow 50K building up whats left of a '70 455 4spd RA GTO I have at the farm. I'd have to hit the lottery to build that mess up. For the most part, my car money goes into my factory roundport projects, thats is when I have excess car money.

['ol Pinion head]

started this reply earlier

and when it all comes down to it, all the (85-100cc chamber) stock Dport cylinder heads mentioned at the beginning of the thread do not know what casting number are stamped on them. They perform very similarly, with the later 5C's & 6X's actually having better low lift flow numbers. Build a 455 with stock head flow 70 model #64 castings, or '70 Bonne casting #15s, or milled head '71 96's, or milled head 6X-4's. Mill the latter two pairs of heads to arrive at 85-87cc chambers. When your done, with same cam, same intake & exhaust, the engine will produce near identical amt of torque up to 5100-5300 rpm. Its only at that point the factory 1.77 slightly larger exhaust valve actually means something IF the engine has the cam & valvesprings to work up there. With stock headflow & heavy reciprocating assembly on any of these, why would one need to turn the 455 any higher, its not going to make anymore power??? This has been proven over & over again. In years past built several fully balanced rebuilt with ARP rod bolts cast rod 455's, I would definitely trust their bottom ends more at 5500 rpm than I would an unknown factory assembled 455 shortblock with stock rod bolts. Point being, with any of the above stock flow heads, why would one buzz the engine up past where its making power on a stock bottom end? Are you just wanting it to stack a rod bearing and kick a rod??? Over the last 12 years for my own keepers everything has received forged rods, too affordable not to buy them.

One thing that seriously needs to be addressed, Compression alone is not the BIG power plus you make it out to be ratt, esp when raising compression from '9.2-1 to 10.25-1, the gains are minimal, much more torque gains to realize in raising the '75 455's C/R up from mid 7's (that's where it will be at with never surfaced 5I's or '76 model 6H's) to the low 9-1's.

When it comes to low compression, any day, I'll take any of my stock headflow 197's over any stock flow 70 model "HO" 64 heads. Bone stock the 197's flow near 25 cfm more on the intake at .500 lift. I've had five pair of 197's flow tested on the same bench & soon will be having the home ported 4X 400 heads I've worked on. Stock flow the '73-74 SD heads flow even more than the 197's & have bigger stock port volume. When it comes to comparing stock engines, the '71 HO was a stronger engine than a '70 455 "HO", period. always get a kick out of '70 455 discussion as the '70 455 "HO" was not even the 2nd most powerful offering in a '70 GTO & the a properly ordered bone stock '71HO GTO was neck & neck with similarly properly ordered bone stock '70 RAIV. Factory installed in the light T-37's the '71 455HO knocked off a few more tenths & was even quicker.

Last thing to address just because you can't as make as much money in one sale for a pair of 6X cores as you can charging folks for '71 96 cores & '70 "64" cores, consider what nearly every major Pontiac engine builder accomplished with 6X's (& near identical 5C's). Until there were quite a few choices of alum Pontiac cyl heads on the market, many Pontiac engine builders routinely built stock head flow 6X 455's & ported head flow 6X's combinations. Over 30 years ago, there was a local in my area using "gimme" (super cheap core) '70 model 15's & '67 model 061's. With the 15's he ported the intakes, opened up & cleaned up the exhausts & installed new valves. Did similar portwork & also installed 7/16 BBC studs & guideplates n the '061's. He also ground the casting numbers off the center ports, LOL Made good compression, flowed really good, & ran harder than stock round port combo's. I know quite a few locals that bought this fellows heads & other ones who turned their noses up at what heads he was selling as well. The latter pretty much got out of shape & today one can see em at the local yocal show-n-shines. No thanks, not where you will find me. Heading out to pull some parts, ck in tonight.

[Lloyd-TX]

Very well stated as always Roger.

Glad to see that you, unlike myself, can respond so eloquentlyto such ill-informed posts as those by my RATT.

[RATTCRUSHER455]

the original question was what heads should he use for max power on the pump by far out the box 64 out does 6x
96 out does 6x
* 197 out does 6x
* 7f6 out dooes 6x
* super duty 16 out does 6x

* the average pontiac guy cannot afford them so it comes down to again 64 or 96 or even 7k3

no port work no valve changes no b.s. just bolt them on and go

again i will sell anything a person wants i wish i could sell more 6x junk i will sell them to people like mc donalds sells mc doubles if there enough people in the world that wants them compare to my top shelf heads 6x is already on my dollar menu

[RATTCRUSHER455]

and for the record, my 70 trans am is real ram air iv, let there be no mistke i may live in florida but not in the magic kingdom and i have plenty of sense thank you, and if i was really into pontiac just for the money i might sell it off but i am not , i do not need the money i rather own one of 88 thank you much in the mean time i will use a 70 xf block with the 614 heads till a good 70 ww surfaces. but one thing is for sure when its all said and done it will run on the pump and make enough power than a 455 with 6x heads thats for sure but anyone of my 455 engines already do that anyways so nothing really to accomplish there. but i still need a ww 455 for my 73 formula found a whole complete parts car with that down here in florida just cant get the owner off the car yet

[Lloyd-TX]

Well, Mr. Rat, certainly no one can deny that you have a vivid imagination.

"Plenty of sense" is up for discussion, IMO, but may I suggest that you brush up on your grammar and punctuation?

[455Grandville]

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

Post some pics of those Formulas ; I'd like to see those; Im a sucker for the 70-73 cars !

[RATTCRUSHER455]

ya i was told i had a vivid imagination once when i was a young kid, but now in my 40's i pretty much made all my dreams a reality and i owe most of it to pontiac parts sales it has done me very very well over the past 25 years , just living the dream under the radar and having lots of fun while doing it . and yes i should proof what i type a little more when it counts i cross my t's and dot my i's but when i am shooting the breeze on this site between customers purchases i am not so concerned,

[muscle_collector]

can we go back to the original discussion about the 75 455-HO t/a that the guy bought??

post some pics whenever that you can. and post the phs if you want to.

[HO Kenny]

Big Hammer
I hope you haven't been completely turned off by the hard headed opinions of a member on this forum.
Your question was simple enough. How do I increase my compresion?
Almost any other pontiac head will do that compared to yours.
Fist I must say no matter what your combo, if you run a stock bottom end and 4.11
gears you will be replacing it or rebuilding it very soon. I'm suprised it hasn't happened yet. Your present engine combo may be is it's own rev limiter. It's not a small block chevy. It may actualy be slower than if it had 3.42.
You can run
#64 10:1 if you have a good cooling system, fuel, exhaust, not to much ingition timing, and high elevation. Even though they are big valve the flow rating is just ok. They were ment for big heavy cars with low end grunt. Replace the 4.11's
1971 #96 9.1:1 heads More ignition advance and sooner. They flow about the same but maybe a bit better than # 64. Replace the 4.11's
#191 Flow is good Needs round port exhaust. They are expensive. Spend the money on some aluminums or getting SD perf to port a set of your favorit D port iron. Replace the 4.11's
#7k3 Similar to # 96 Not as good high lift better low lift. Replace the 4.11's
#48 stamped 7H or 3H3 for 9:1 should put in the big exhaust valves. OK flow. Replace the 4.11's
#5c stamped 4 for 9.25:1, 8 for about 8.9:1 same as above. Replace the 4.11's
#6x stamped same as above for compression but the ports were redesigned and flow as good as or better than any other "D" port. Put the big exhaust valve in it and it is even better.
Replace the 4.11's
#64 are expensive because they could be put on a 400 and have about 8.85:1 not because they were the best head. At the time everyone thought all big valve "d" ports flowed the same. They don't, but can be made to with time or money.
#96 a bit cheaper
Some of the rest can be had for cheap or even free.
6X-8 $100-150
6X-4 $200-300
The pontiac performance cams are left over from the hi comp. days. Many of the newer cams work much better with medium comp. They build up cylinder pressure rather than bleed it off. Shorter duration less overlap and more lift. Cannot have weak valve springs.
The only one you could use the 041 cam would be the # 64. But why would you there are much better newer grinds out there. I know lots of people get them to work with lots of planning and tuning.
I have a 68 firebird with your engine with # 96 heads, factory cam with 1.65:1 roker arms. It works well.
I have a 71 ho 455 with a small modern cam and 3.08 gearing. It will easaly pull away from my 1968 firebird. I can run it or regular if i want to but i don't. It is very frendly to drive when you want it to and very mean when you push the loud pedal.
Do not run a stock 455 bottom end past 5200. replace the 4.11's

[RATTCRUSHER455]

right from mccarthy

Best performance head 1970 Ram Air IV

Best intake port 1969-70 Ram Air V

Best exhaust port 1 968 1/2 Ram Air II

Best D-port head No.16, No.48, No.12 (tie)

Best low-compression D-port head No.96(1971) big exhaust valve already there

Best low-compression post-1972 head No. 6X

Best balanced head (exhaust to intake) 1963 421 SD

Best low-lift (under .400) head 1967 No.670

Worst exhaust-to-intake port ratio 1969-70 Ram Air V

Worst intake-to exhaust ratio 1968 1/2 Ram Air II

Biggest surprise Intake port, No.17 350 head

Biggest disappointment 1969-70 RA V, 1973-74 455 SD (tie)

Biggest "sleeper" 1975 No. 5C

Most undercammed 1963 SD, 1971 455 HO, 1973-74 455 SD (tie)

Most underexhausted 1964 GTO (No.9770716)

Most potential for porting 1973-74 455 SD, 1968 1/2 RA II (tie)

[RATTCRUSHER455]

1970 No. 64 (1970 455 GTO & 455 GP)
Date cast: I099 Grade: 2 (worn guides)
Valve sizes: 2.11 /1.77
Intake(S) Flow (cfm) Exhaust(S) Flow (cfm) Exh./Int.
.100 65 .100 38 .58
.200 111 .200 75 .79
.300 138 .300 98 .71
.400 148 .400 111 .75
.500 153 .500 120 .78
.600 156 .600 125 .82

1971 No. 96 (1971 400-cid 8.2:1 CR; 96 cc D -port)
Date cast: G 030 Grade: 1
Valve sizes: 2.11/1.77
Intake(D) Flow (cfm) Exhaust(D) Flow (cfm) Exh./Int.
.100 67 73 .100 33 38 .51
.200 115 122 .200 74 74 .62
.300 144 148 .300 99 96 .67
.400 160 160 .400 111 105 .68
.500 165 166 .500 118 112 .69
.600 169 170 .600 122 118 .71


1975 No. 5C (1975 350/400/455-cid D-port)
Date cast: F184 Grade: 1
Valve sizes: 2.11/1.66
Intake(D) Flow(cfm) Exhaust(S) Flow (cfm) Exh./Int.
.100 63 63 .100 42 .67
.200 115 115 .200 78 .68
.300 143 146 .300 103 .71
.400 161 160 .400 118 .74
.500 164 165 .500 127 .77
.600 170 169 .600 131 .77

1975-79 No. 6X (1975-76 400/455 & 1977-79 400 D-port)
Date cast: 0185 Grade: 2 (worn guides)
Valve sizes: 2.11/1.66
Intake volume (1 port): 154.0 cc's
Intake(S) Flow (cfm) Exhaust(S) Flow (cfm) Exh./Int.
.100 67 .100 51 .76
.200 112 .200 83 .74
.300 140 .300 96 .67
.400 158 .400 104 .66
.500 163 .500 110 .67
.600 167 .600 113 .68

so lets look at this buy a pair of 96 heads for 450.00 on the high side my favorite price to sell them for or buy some 6x 4 for 150.00 my typical price to sell that junk for and then go pay a jack load to a speed shop to retrofit to a bigger valve and hope they are not a hack and create bigger problems,,,, did not list the 455 h/o heads because most folks cant afford them

trust me if 96 heads where made from 1975-79 and millions were made like the 6x head was, the 6x would be crushed even at a faster rate than they are today its the limited supply of the 96 heads and the cost that follows makes the 6x the only next natural option . in the 70''s 80's and 90's 96 was the way to go for low compression power , but like all the good stuff does all the supply dried up because the smart folks started to hold many sets back. the better money spent is buy the big valve heads up front and keep your money in your pocket instead of donating those funds to a machine shop and hope to god they machine the heads right to shove bigger valves in

[RATTCRUSHER455]

also the money you spend on a 96 head or a 64 head will always hold its value and going higher everyday a 6x 4x 5c i have two words for you "Diminished return" i sell heads for a livingand all kinds of poncho parts and have done so for over 25 years now bring a pair of 6x in for sale or trade if you get $10.50 per hundred consider yourself lucky

[big hammer]

Originally Posted by HO Kenny

Big Hammer
I hope you haven't been completely turned off by the hard headed opinions of a member on this forum.
Your question was simple enough. How do I increase my compresion?
Almost any other pontiac head will do that compared to yours.
Fist I must say no matter what your combo, if you run a stock bottom end and 4.11
gears you will be replacing it or rebuilding it very soon. I'm suprised it hasn't happened yet. Your present engine combo may be is it's own rev limiter. It's not a small block chevy. It may actualy be slower than if it had 3.42.
You can run
#64 10:1 if you have a good cooling system, fuel, exhaust, not to much ingition timing, and high elevation. Even though they are big valve the flow rating is just ok. They were ment for big heavy cars with low end grunt. Replace the 4.11's
1971 #96 9.1:1 heads More ignition advance and sooner. They flow about the same but maybe a bit better than # 64. Replace the 4.11's
#191 Flow is good Needs round port exhaust. They are expensive. Spend the money on some aluminums or getting SD perf to port a set of your favorit D port iron. Replace the 4.11's
#7k3 Similar to # 96 Not as good high lift better low lift. Replace the 4.11's
#48 stamped 7H or 3H3 for 9:1 should put in the big exhaust valves. OK flow. Replace the 4.11's
#5c stamped 4 for 9.25:1, 8 for about 8.9:1 same as above. Replace the 4.11's
#6x stamped same as above for compression but the ports were redesigned and flow as good as or better than any other "D" port. Put the big exhaust valve in it and it is even better.
Replace the 4.11's
#64 are expensive because they could be put on a 400 and have about 8.85:1 not because they were the best head. At the time everyone thought all big valve "d" ports flowed the same. They don't, but can be made to with time or money.
#96 a bit cheaper
Some of the rest can be had for cheap or even free.
6X-8 $100-150
6X-4 $200-300
The pontiac performance cams are left over from the hi comp. days. Many of the newer cams work much better with medium comp. They build up cylinder pressure rather than bleed it off. Shorter duration less overlap and more lift. Cannot have weak valve springs.
The only one you could use the 041 cam would be the # 64. But why would you there are much better newer grinds out there. I know lots of people get them to work with lots of planning and tuning.
I have a 68 firebird with your engine with # 96 heads, factory cam with 1.65:1 roker arms. It works well.
I have a 71 ho 455 with a small modern cam and 3.08 gearing. It will easaly pull away from my 1968 firebird. I can run it or regular if i want to but i don't. It is very frendly to drive when you want it to and very mean when you push the loud pedal.
Do not run a stock 455 bottom end past 5200. replace the 4.11's

thanks alot for all the info! i ran all the numbers and a .030 over 455 with a .040" head gasket with the stock pistons (i used +8 cc's for the pistons?) and 64 heads would be around 9.7:1 compression which is doable with premium fuel. like i said i would be lucky to just run a few tanks of fuel through it per year anyway.

for me in all my retardation, i would like to have actual 455HO heads on my "455HO".

however, what are these heads usually worth?

and i'm thinking of ditching the 4:11's! lol

[big hammer]

just got the car home last night

[big hammer]

i have the phs documents but just the faxed ones right now. they're kinda hard to read. it is a legit numbers matching car, except the interior is supposed to be white.

[muscle_collector]

nice. find the build sheet and see if it came with honeys or rallyes. seats look like 78 newer. with just a few mods you can make those 455 's run really well. congrats on the purchase and post the phs when you get it.

[2manyT/A'S]

Good lookin' 75!

When you get deeper into it,I can explain why your steering wheel / horn cap alignment looks messed up.

What's that white stuff all over the ground?

[johnta1]

What's that white stuff all over the ground?

X2!

TA looks good.

Here's a link to a 75-76 455 TA Registry
75/76 455 TA Registry