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Discussion Starter #1
I delivered a ‘71 long block to the local Pontiac guru today, having him build a 461 stroker over the winter.
The block has ‘71 #96 heads and my builder believes that these heads, with some porting and clean up, will work really well on a 461 built to somewhere around 425hp
What’s the consensus here?
Are the iron #96 heads a decent (cost effective) choice?
Is there anything in particular that needs to be attended to?

I realize that there are likely 4 novels worth of possible replies here, lol, but I needed to ask the question

Thanks everyone


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I think 425 is very conservative.
Agreed. A great deal will depend not only on how well the heads flow but on the cam profile you choose. The first incarnation of my 461 build made 500 hp / 535 lb ft on the dyno at break-in with the factory iron intake, 800 cfm QJet, 72 cc iron heads, 9.5:1 compression, and a solid roller that was really somewhat mild for a roller (236/242 @ 0.050, 110 LSA, 0.600 net lift at the valves) and it was running a tad lean at 13.7:1 air/fuel at the time. That incarnation had NO quench at all in the cylinders because of some really ugly things I had to do to it in order to get compression down to 9.5:1 for pump gas. The pistons had >round< dishes in them (so zero quench pad area) combined with 0.075" thick head gaskets. I had on it at the time a set of gen-u-wine #722 '69 RA IV heads that I really really wanted to run, so that's what it took.

I ran out of time to play with it on the dyno, but I'm guessing there would have been "more in it" with a richer fuel mixture and perhaps a little more timing.

Bear
 

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Discussion Starter #4
Agreed. A great deal will depend not only on how well the heads flow but on the cam profile you choose.

Bear
Thanks Bear - I’m planning on a using a Butler/Ross or Butler/Eagle setup with my #96 heads and RAR RM-2 D-port exhaust manifolds.
I don’t have an iron intake so intake, carb and cam are all areas that I need to investigate.
I am all ears when it comes to advice

I’ll be putting a built TH400 behind it and going back to the 3:55 gears (I have 3:90 in it now)

The car is my summertime daily driver so I’m not aiming for a 10 second strip car - just something a little beefier than my stock 400 that’s in the car now.

Any recommendations you may have on a cam, rockers and valve train recipe would be greatly appreciated.

Oh, my builder also recommends that I go with a Holley 850 VS

Joe


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Any recommendations you may have on a cam, rockers and valve train recipe would be greatly appreciated.

Oh, my builder also recommends that I go with a Holley 850 VS
Holley 850... Is your builder a Chevy guy? :D

The previous incarnation of my engine in my '69 that had the horrible quench properties was running a QJet, 3.50's (Moser 9"), strong TH400 - and it ran 11.80's at the track (in Drive, auto-upshifting at about 4800 - because I didn't yet have a rev limiter in it).

Plus, we also took it on the full Power Tour in 2013 which was from Arlington Texas to Concord NC - and back with zero problems. At 70mph with those gears and the converter I had in it at the time, 70mph was in the neighborhood of 3200 rpm, which was a little much.

I "pre-emptively" converted the car to hydroboost braking out of concern for idle vacuum, but I needn't have worried as it turns out. That cam made 13-14 inches at idle as it turned out, probably because, being a roller, overlap wasn't all that severe. A flat tappet cam with similar duration would have been "worse" as far as idle vacuum.

The rest of the story on that build is that after I got it all together and had been driving it for some time, it developed a crack near, but not through, the #6 exhaust seat and started leaking coolant into that cylinder. I tried once to have it repaired, but it didn't hold, so I ended up replacing them with a set of 72cc round port Edelbrocks. That let me go back to standard head gaskets, but the quench was still horrible due to those big round dishes. Even with that I was only able to get it "back" to 10.0:1 when I think with those heads it really should be at 10.5:1

That incarnation - the cam I described in the previous post, the E-heads, QJet, and 10.0:1 with horrible quench is the combination that ran 11.80's in Drive.

For my most recent build, triggered by a rocker arm going away and putting shrapnel through the engine (at least partially my fault if not 100%) - which is a whole 'nuther story - I "stepped it up" with quite a bit more cam, more compression, Northwind intake, and an AED HO 850 with annular boosters. I fought with that dad-blasted carburetor for 12 -- solid -- months trying to get it right in all operating regimes, so in my experience tuning a Holley is nowhere NEAR as easy as everyone claims. Out of the box it was "almost" right, the one exception being part throttle / light cruise - where it was running so rich that I had to constantly keep changing the oil because of all the raw fuel that was washing into the crankcase. Getting it to lean out "enough" at cruise without messing it up everywhere else is what took me 12 months to accomplish. That experience really made me wish that I'd stuck with the QJet, but I had convinced myself that the other changes I'd made meant the engine needed "more".

My personal experience running a solid roller valve train on the street is that with modern parts, you don't really have to adjust valve lash that often - maybe a couple times a year, under normal circumstances, as long as you use good parts and that includes lifters that have positive oiling to the rollers and needle bearings instead of relying on 'splash'.

I'm hesitant to make specific cam recommendations because there are too many variables involved, but maybe sharing my experiences and results will give you some ballpark ideas.

Bear
 

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Discussion Starter #6
Holley 850... Is your builder a Chevy guy? :D

The previous incarnation of my engine in my '69 that had the horrible quench properties was running a QJet, 3.50's (Moser 9"), strong TH400 - and it ran 11.80's at the track (in Drive, auto-upshifting at about 4800 - because I didn't yet have a rev limiter in it).

maybe sharing my experiences and results will give you some ballpark ideas.

Bear
Thanks again man - I’ll be picking your brain down the road, no doubt

Joe


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Discussion Starter #7
So, I have decided to go with Butler’s HR 8022SP custom grind Comp cam.
Specs are 282/288 Advertised Dur. / 230/236 Dur. @.050” / .510/.521 Lift w/1.5 Ratio Rockers 112 LSA

The block is .040 over so it’s a Butler/Ross 462, and I’ve ordered the SD super brace kit as well.
Intake will be the Edelbrock Performer RPM that’s sitting behind my couch, and I just dropped the heads off to be ported, polished and rebuilt. I asked the machinist to aim for 220-240 cfm.
I’ve decided to stick with my 2004R as it’s built and works well, however I’ll have to change out the torque converter to something more suited to the build.
I’m going to go with a DUI ignition system.

I still have not decided on a carburetor.

And that’s where I’m at so far . . .

Joe


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I use a Quick Fuel Technology (QFT) 780 VS.......Holley owns quick fuel...just go to Holley web and under brands click Quick Fuel....much more tunable than a standard Holley..

all the idle and high speed air bleeds are changeable mini jets, so are the PVCR’s, the vac secondary has the same springs to change, but also has a fine tune with a screw..

4 corner idle, see thru sight glasses, mine is jet coated black..called the Black Diamond to reduce heat....you will need an adapter to fit the intake like with a Holley..

all the parts are easily avaible direct from QFT.......when you have trouble with circuits, no drilling, you can change the air bleeds, etc.....check em out....just another way to go
 

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Discussion Starter #9
Thanks for the tips LeMans guy



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Or find an 800 CFM QJ off a Buick 455 or a Cadillac 500
 

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1971 GTO resto mod. Modified 428 HO, 4 sp (built by midwest muncie) Dana 60, 3.55 rear
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Soberjoe,
Your block is identical to the one originally in my 71. For what it's worth, here's my two cents:
the #96 heads should work well for a stroker as the CC's are 96. The biggest issue will be their ability to breath enough. Not that they won't work, just keep in mind the dynamics of the motor around given RPM's. what's your stroke length??
If you dropped the heads off to be worked over, it might be worthwhile to take your intake to them to match your head ports to the eddy intake ports since the eddy RPM intake ports were designed around the taller RA IV series. For a stroker it's all about breathing and D ports were always a little short for capability in that department. 220-240 CFM is asking a lot of those particular heads. I've attached an online data sheet from Stan Weiss which put together flow data from a multitude of heads. I think the best flowing numbers from 96 heads came from a set of Nunzi ported heads.
The SD braces are certainly not a bad choice since Pontiac's are known to be weak for bracing in the lifter galley area. BUT unless you plan on running some wild stage 5 type of mechanical roller they might not be absolutely necessary. Have you run any data through a dyno sim program to give you ideas about projected HP/TQ? I've got a dyno sim program and would be happy to run some calc's for you based on your parts selection.
As for the cam selection, I'm not a fan of Comp cams. They've had a lot of issues around material from their supplier, but the specs you stated should give you good idle quality and good vacuum.
As for the carb choice. Everyone has their favorite. I've never run a Holley so I can't say anything about them. The 850 CFM size might be a little big unless you plan on running consistently above 5,000 RPM's. Just remember the bigger the carb on a given motor the less low end response you'll have. Wallace racing web site has some good calculators for carb sizing.
And that is my 2 cents.. Okay 2.5 cents..

Stan Weiss' - Cylinder Head Flow Data at 28 Inches of Water -- DFW / FLW Flow Files for use with Engine Simulation Software
 

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Discussion Starter #12
Soberjoe,
Your block is identical to the one originally in my 71. For what it's worth, here's my two cents:
the #96 heads should work well for a stroker as the CC's are 96. The biggest issue will be their ability to breath enough. Not that they won't work, just keep in mind the dynamics of the motor around given RPM's. what's your stroke length??
If you dropped the heads off to be worked over, it might be worthwhile to take your intake to them to match your head ports to the eddy intake ports since the eddy RPM intake ports were designed around the taller RA IV series. For a stroker it's all about breathing and D ports were always a little short for capability in that department. 220-240 CFM is asking a lot of those particular heads. I've attached an online data sheet from Stan Weiss which put together flow data from a multitude of heads. I think the best flowing numbers from 96 heads came from a set of Nunzi ported heads.
The SD braces are certainly not a bad choice since Pontiac's are known to be weak for bracing in the lifter galley area. BUT unless you plan on running some wild stage 5 type of mechanical roller they might not be absolutely necessary. Have you run any data through a dyno sim program to give you ideas about projected HP/TQ? I've got a dyno sim program and would be happy to run some calc's for you based on your parts selection.
As for the cam selection, I'm not a fan of Comp cams. They've had a lot of issues around material from their supplier, but the specs you stated should give you good idle quality and good vacuum.
As for the carb choice. Everyone has their favorite. I've never run a Holley so I can't say anything about them. The 850 CFM size might be a little big unless you plan on running consistently above 5,000 RPM's. Just remember the bigger the carb on a given motor the less low end response you'll have. Wallace racing web site has some good calculators for carb sizing.
And that is my 2 cents.. Okay 2.5 cents..

Stan Weiss' - Cylinder Head Flow Data at 28 Inches of Water -- DFW / FLW Flow Files for use with Engine Simulation Software
Good advice Jim K, thank you.
I did bring the intake with the heads at the request of the guy doing the work for precisely that reason - port matching as best as possible. The exhaust guides will be machined to accept positive seals, and bronze guides fitted all around. Straight 7/16” studs will be used in place of the stock shouldered 7/16”-3/8” studs.
At the end of the day, if he gets those heads flowing 220cfm or better I’ll be more than happy I’m sure.
He likewise said that 850 was too big on the carb choice. He suggested 750 was more than ample, but he is not at all a fan of any of the Holley sub-brands like QFT, so I’m going to wait and see what he recommends after final-flowing the heads.

Final bore at .040 over is 4.16”
Stroke length is 4.25” with 6.800” rods.

Please feel free to plug the numbers in and see what you come up with,

Joe


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Greetings Joe,
I ran some numbers through the sim program. I had to make a few assumptions around the head gasket. I didn't add any cam advance into the program, although your motor would most likely benefit from about 4 degrees advance install.
One thing I thought of this morning is that the Eddy performer RPM intake seems to be a very good intake with a good track record, BUT one issue is that it is 1.5" taller than a stock manifold, which by itself is not a bad thing but it might limit you on how tall your air filter can be. Most factory filters are around 3" tall but due to the intake, you might be limited to 2.5" or less for filter height. Reason i mention that is again, with a stroker motor, better breathing is a bigger deal than a stock stroke. Attached find some of the pages from the dyno sim. These numbers are indicative only and not exact. Exact numbers need to come from hooking the motor to a dyno and running it. I used the head flow numbers from the Nunzi port job since they were closest to what you are hoping to achieve.
I've attached the program results in PDF.
 

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Here are some things that might be helpful. I am sure your guy doing your porting job is good at it and has most likely done it before, BUT.. Pontiac heads are different from other heads (as one would think) and to get the maximum flow, they respond better if certain aspects are followed when porting. also, the three angle valve job is usually different on a Pontiac than other. All of this comes from a book that's long been out of print called Pontiac high performance engine design and blueprint by Craig Hendrickson and Kern Osterstock.. Two Pontiac Gurus..
intake port dimensions pg 54.jpg intake port dimensions pg 56.jpg intake_exhaust flow pg 51.jpg porting  pg 59.JPG porting  pg 63.JPG
 

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Discussion Starter #15
Hey thank you for this Jim K - I appreciate the effort that you have put forth to lend a fellow goat owner a hand. I plan on sending this info - for reference purposes - to my head builder cause there's nothing to lose by sharing information (y)
And truth be told he ha only worked a few Pontiacs, so it can't hurt, lol
 

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Discussion Starter #16
The #96’s went on the bench today, getting a baseline before porting.



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The #96’s went on the bench today, getting a baseline before porting.



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Should be interesting. The average for stock heads seem to be around 205 CFM's. I did my own work on a set of 7K3 heads, used Ferrea RA IV length stainless steel 2.11" / 1.77" valves, and 2 angle valve job as my machinist said I had opened up the throats to where a 3-angle wouldn't work. I had 1 chamber flowed and this is what I got. My cam choice won't be .600" lift, but will be about .500" on intake and around .525" on the exhaust using 1.65 rocker arms.

______________INTAKE_______EXHAUST
Lift******************CFM**************CFM
.100*****************94.5****************48
.200*****************157****************107
.300*****************201****************142
.400*****************214****************167
.450*****************224****************173
.500*****************230****************178
.550*****************234****************178
.600*****************237
 

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Should be interesting. The average for stock heads seem to be around 205 CFM's. I did my own work on a set of 7K3 heads, used Ferrea RA IV length stainless steel 2.11" / 1.77" valves, and 2 angle valve job as my machinist said I had opened up the throats to where a 3-angle wouldn't work. I had 1 chamber flowed and this is what I got. My cam choice won't be .600" lift, but will be about .500" on intake and around .525" on the exhaust using 1.65 rocker arms.

______________INTAKE_______EXHAUST
Lift******************CFM**************CFM
.100*****************94.5****************48
.200*****************157****************107
.300*****************201****************142
.400*****************214****************167
.450*****************224****************173
.500*****************230****************178
.550*****************234****************178
.600*****************237
I will post all of the before-and-after numbers when I get them


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Keep us posted Joe!.. Interested as to the numbers that come out before and after..
 

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Discussion Starter #20 (Edited)
Stock 96 D port baseline

100—— 78.6 ——- 54.1
200—— 135.5—— 107.2
300—— 178.3—— 140.5
400—— 197.1—— 162.4
500—— 204.7—— 177.8
550—— 204.5—— 184.0
600—— 204.6—— 189.2
700—— 208.0—— 197.4


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