[Judge273]

I can't read the exact time...is that a 12.4 something? Scott Tiemann got that thing moving!

[OVERULD]

I'm close to that car if anyone needs me to go look at it. He also says that he has a 4-speed car coming up. I think this may be the second or maybe third time around for this car on the 'bay. It is a pretty car!

BJ

[2manyT/A'S]

Auctions OVER with NO takers @ $68,000K.

Two years ago,I bet it might have come CLOSE.

I do recall seeing it go through (no sale) last fall,as well.

[1971455HO]

You are right, it's beautiful. I want to ask two questions though. Please remember,I'm no expert. My car was ten years old when I got it and a bunch had already been changed. Is the Firebird emblem above the cigarette lighter correct? Mine didn't have it. Also, when did the "Radial Tuned Suspension" appear on TA's engine turned bezel dash?

[68bird400HO]

Originally Posted by 1971455HO

You are right, it's beautiful. I want to ask two questions though. Please remember,I'm no expert. My car was ten years old when I got it and a bunch had already been changed. Is the Firebird emblem above the cigarette lighter correct? Mine didn't have it. Also, when did the "Radial Tuned Suspension" appear on TA's engine turned bezel dash?

Yes, that dash bezel is correct for 1971 (actually late 70 through 72). The RTS emblem didn't appear on the dash bezel until 1975.

[OVERULD]

The 455 H.O.........Yeah, I got one! And I'm lovin' it!!!


Thanks Mark for validating yet again, why I had to have a GTO with this motor and a 4-speed. I noted in the HPP article that the M20/M21 seem to be the preferred 4-speed models. I have the M22 and I'm running the original GM 12-bolt with 3.31:1 gears because my car is an AC car. How do you think this combo would perform...Can you elaborate on that just a little?

(I've got original numbers matching block, stock crank, pistons, rods, stock 197 heads, intake, 7041273 carb, stock 068 cam, R.A.R.E. 2.25" exhaust manifolds, no H or X pipe, stock distributor with Pertronix coil and points replacement.)

Thanks,
BJ

[Lloyd-TX]

Quick question, Mark . . .

Are the R.A.R.E. 2.45" outlet Ram Air / HO / SD exhaust manifolds considered to be legal on the PS engines?

TIA.

[74 SD455 Formula]

Mark,
First of all I would like to say thanks for all of the input.Could you please tell me ( us ) what brand Cam Shaft you use (or recommend ) and what you have done special ( grind ) to them and how there installed ? I am having a HO 455 rebuilt for my 72 GTO and greatly enjoy reading your little articles on these subjects.I was so prepared to put in a Hydrulic roller cam,but after reading alot of the info you are offering I feal like I am wasting my time with over kill.Thanks for any future info you have to offer.

[bird72]

I've read all the pages in this thread last night and today. If I may humbly join this club as a bastard stepchild member... I am looking at a pile of parts, that in the next year will be put in action. Hard to believe I actually got some HO heads after being into Ponchos so many years.... and resigning myself to D port heaven..... so my 72 Formula 400 will continue the non matching number deal, but in a bit better style. I'll use the bottom end I have running now, a 4 bolt 455 (not HO).... but swap the 96 heads for the HO's.

End result:
YC 455 w 4 bolt caps I added
forged rods (undecided type, moderate cost) (have stock rods now)
HO top end
stock valve train
good springs
all balanced of course

(I also have option of leaving bottom end alone, it only has 2000 miles on it although 12 years old!)

above coupled to: 12 bolt 3.55 posi and Turbo 400

My goal is a 5200 rpm and under street motor. Low compression.

I am running a Performer RPM cam now (RA IV similar) and want to de-cam a notch for streetability and manners, and bring it down to a 1000-5200 RPM powerband with maximum torque and HP in that range, which from everything I've read here is HO's forte.

Cam suggestions?

[1971WARBIRD]

Originally Posted by bird72

I've read all the pages in this thread last night and today. If I may humbly join this club as a bastard stepchild member... I am looking at a pile of parts, that in the next year will be put in action. Hard to believe I actually got some HO heads after being into Ponchos so many years.... and resigning myself to D port heaven..... so my 72 Formula 400 will continue the non matching number deal, but in a bit better style. I'll use the bottom end I have running now, a 4 bolt 455 (not HO).... but swap the 96 heads for the HO's.

End result:
YC 455 w 4 bolt caps I added
forged rods (undecided type, moderate cost) (have stock rods now)
HO top end
stock valve train
good springs
all balanced of course

(I also have option of leaving bottom end alone, it only has 2000 miles on it although 12 years old!)

above coupled to: 12 bolt 3.55 posi and Turbo 400

My goal is a 5200 rpm and under street motor. Low compression.

I am running a Performer RPM cam now (RA IV similar) and want to de-cam a notch for streetability and manners, and bring it down to a 1000-5200 RPM powerband with maximum torque and HP in that range, which from everything I've read here is HO's forte.

Cam suggestions?

got to thinking,go into (your best pontiac stories)go back to the top of page 3 and see a story(lost in the smoke)one of the reasons i'll always love HO's.if i could keep my foot out of it that car would get 16 mpg on the interstate,or go sideways if i couldn't.

[Jim Robertson]

Mark and company,
Thank you, Thank you, Thank you for the very informative post here...plus the magazine articles. Great info that did not come easy nor cheap.

From one enginehead to another...you are the man!
Jim

[Mark Weymouth]

HO's you gotta love them. Twenty five years ago when I was 16 I picked up my first HO motor and intended to drop it in my first car. In the end I still have my first car and left the numbers motor in. Good thing as my HO T/A now carries that motor while the numbers motor is slumbering its life away. Even as a dumb young kid I figured out that HO's are not just another round port motor but something truly special.

BJ: The M22 carries the same gear ratio's as the M21 and genarically us Pontiac PS guys tend to call them all M21's. Not sure why. Kind of like my cousin who is an original owner of a RA II convert Goat and he always called it a RA IV when I was a kid. Habbit I suppose. I have the stock M22 in my HO. It works great. We have a 3.73 gear and Scott was hitting consistent mid 1.90 sixty foot times this fall with it. That puts him in rare company as only about 20 of the 152 cars at the PS race got below 2.0 short times. He was one of only two non Corvette 4spd cars to do so. Bruno and his RA IV Goat was the other as I recall. I made one pass in the car all weekend and hit a 1.94 short time. The M22 with a 3.73 is an easy car to drive, well relatively easy as the one two shift sometimes can catch you out or point you East West on a North South track which is always less then fun.

Lloyd: You touch on a sticky spot at the PS races. If you cert your car they absolutely are a no no. If you are running at the head of the pack for your type of car and showed up with them we would likely ask you to change them for the following year. We know they have shown up and we have seen them. So far though those cars have not set the world on fire and they have been mostly left alone but a subject of on going conversation how to handle them. Some mid-year Corvette's have the same thing going on. The 1965 and older small blocks have 2.5" outlets for their manifolds and 1966 into the C3's have 2" out lets. Some later guys try sneaking on the older manifolds. Our testing of an L79 with all combo's kind of proved that they were not really an advantage at all or even somewhat. As a tech and racer I would prefer to not see them around for our venue. It makes it easy on us to not have to confront the situation if some one is really laying down the times. Our racing is for fun and not really about who brought the fastest car overall. There was a pecking order to these cars back in the day and it should still be there today. For us HO fans we just so happen to have a rare quantity in that our low compression motor will out run most high compression motors from the brand x guys. Sure is fun to beat a big rep high compression motor with a low compression motor that has a broom stick for a cam.

74 SD Formula: We have used several different cams. Wolverine and Melling have both been consistent performers for us. We had a short stint with Lunati cams that came up very poorly for us. We lost two AMC motors and a HO due to cam wipe out. We break all motors in on a stand carefully. No inner valve springs, Brad Penn break in oil or equiv., GM EOS (now discont.) or equiv. cam break in additive. When we are done we change the oil but stay with those items again even on the dyno. We want safety first at the expense of higher numbers. We have traded that combo out at the end of a dyno session once for Brad Penn racing synthetic oil. We got almost 6 hp as I recall. Anyhow the Lunati had great specs for a RA III/HO street motor. Being at the NHRA max lift rule of .424 on both sides but having a touch of extra .050 duration of 220/228. This cam is not legal in our racing but the numbers looked great for street motors. It did make good numbers on the dyno also. But in the end nothing really better then what we now have. I actually grind our own cams often now for Dan, Scott and I. But as myself and them are not really into cam sales we do not readily have them around or sell them. Usually if Dan is doing a motor or possibly Scott they give me a heads up and I have one made. I also help with a few motors a year for freinds beyond my own or brothers. As this is a hobby for me and I am already way to involved in my hobby I have kept them closely held so as to not let it consume me anymore then it has.

With that said when I am doing a non PS or part time racer we look at the engine program as a whole. I have changed center lines to match the project. This can also be done with Comp or Crane. They will sell you their 068 cam for example with your specified centerlines. I did that early on before creating our own cams. The Lunati experience tainted my trust in many companies and at that time we ran into several PS AMC projects and a Boss 302 project that no one made repo cams for. That got the ball going to replicate the originals by using NOS cams as our guide. This long winded dissortation I suppose is to say I might sell a cam here or there on a special basis or I would certianly help you find the correct center lines (lobe seperation) for your project and you could order a Comp or Crane that way. We have tested all manner of center lines and have a pretty solid idea what works best for each motor, compression ratio, trans type and rear gear. It does matter.

Bird 72: A properly set up 068 will give you 5200 rpm. We shift my HO at 5200 and it hangs in pretty tough until 5500. After that it signs off quickly.

Strictly speaking there is not much wiggle room on the cams in PS rules. Lobe seperations being altered is getting more and more attention now. Not good attention. I think that Dan and Bob are likely going to shut that down soon. But for all of you who likely will not or can not come and play with us it makes great sense. You have maxed out your stocker with out altering its nature. Except Lloyd who I know wants to come play with us as soon as possible. A general rule on most any 389/400/421/428/455 a 110 intake 114 exhaust and 112 lobe center line works well. The 350 HO's both '68 small valve and '69 big valve have their own set of rules. The 110/112 combo has great bottom response and will give several hunderd extra revs while not falling off as quickly after it peaks hp. It is a very tolerent setup for ping/gas issues also.

You guys sure have sucked a lot of info out of me!!!

Thanks, Mark

[OVERULD]

Thanks a million Mark! I really want to try to make it to one of your events. Maybe Virginia.

BJ

[Lloyd-TX]

2.25" outlet manifolds it is, then.

Thanks for answering that question, and all the other questions, Mark.

[2manyT/A'S]

GREAT INFO,Mark!

Keep it coming!

This question is not really engine related,but as far as PS tech goes,are urethane body mounts,engine mounts & suspension bushings considered legal?

Can you post some pics of your 71 T/A?

Show us the rest of your HO.

The engine shot in the magazine was COOL. (it's looks so...,er....,well..., stock?

[Mark Weymouth]

I will have to try and remember to post some pictures when I am home. The front sway bar pix in HPP PS Prep School article is of the HO does that count? The rest are mostly from my RA IV T/A, is that a fair substitute? If you envision the blue over spray as white on the bottom side they are the same... Ok I am trying to get away with being lazy.

I have poly graphite bushings in the suspension of my HO. The car only has 30K on it and I left the stock body mounts alone. The car was always stored and they were in perfect shape. You could change them though to poly ones if you choose. Same with the engine mounts. I used fresh motor mounts when the race motor went in.

Mark

[mmarx]

Mark, as always, great info...I really enjoyed this comment:

"Sure is fun to beat a big rep high compression motor with a low compression motor that has a broom stick for a cam"

That's priceless...

Thanks again,

Mike

[bulletpruf]

Wow, great thread! Think I'm going the PS route with my RAIV 70 GTO. Have almost all of the engine components assembled (need crank, carb, dist), so time to start doing a bit more research...

Thanks,

Scott

[threefidee]

Originally Posted by 2manyT/A'S

GREAT INFO,Mark!

Keep it coming!

This question is not really engine related,but as far as PS tech goes,are urethane body mounts,engine mounts & suspension bushings considered legal?

Can you post some pics of your 71 T/A?

Show us the rest of your HO.

The engine shot in the magazine was COOL. (it's looks so...,er....,well..., stock?

Here are a few pics of Mark's car. Sorry it took so long but she just started working again.

[2manyT/A'S]

Will be interesting to see what these will fetch.

http://cgi.ebay.com/ebaymotors/ws/eB...m=200234814278

You don't see a full set of them for sale very often.