[HWYSTR455]

Originally Posted by Formulajones

I was one that did homework on the ram air setup. Dad bought his 69 Goat new and been racing it since the 80's. The car has always run it's best times with those scoops functional and the factory air cleaner setup in place. Had numerous 455's in the car during that period.

More recently in fact I've modified the setup with a Glasstek hood and molded in an air box using a L88 style drop base to seal the hood to only fresh outside air, still uses the GTO scoops. Basically it now mimics how the 68 style was setup. The car now has a 571ci. engine.
Now with a Sniper installed I can datalog. IAT's are the most telling. Pumping gas and sitting still getting heat soaked the IAT's are already 130 degrees after 5 minutes. Pulling out of the station and within a mile of cruising 30-40 mph the IAT's drop to within a couple degrees of outside ambient temps. You can actually watch the IAT's go up at a stop light, and come back down when the car starts moving.
At the track where the car traps 128 mph, during the datalog the IAT's are dropping throughout the pass and actually getting about 20 degrees below ambient temps at those speeds.

The setup works very well.

Either way I like the build. I like the 96 heads on the 68 GTO idea, and how I would have built it. Iron intake would be more correct for 68 but I much rather prefer the aluminum version with the separate heat crossover. I've been running it for a few years now on mine and was a big improvement over heat soak while still keeping the divorce choke functional.
Not a fan of the rockers as mentioned. I only use Harland Sharp or Crower steel rockers on my builds anymore. Otherwise a nice combo of parts that's going to be a blast to drive.

I thought it was an article, maybe out of High Per Pontiac? Some reason I though maybe Rocky did the article, but can't recall at the moment.

Check vacuum, see if it starts pulling vacuum over x RPM. My understanding is it's a flow restriction, and don't disagree that IATs would drop.

I bet IATs drop even with an open element under the hood, as air starts flowing and evacuating from the underhood area, so think a comparison would be in order to determine the gains/improvements.

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[HWYSTR455]

Originally Posted by Bruce Meyer

I put a 68 ran air setup on my 69 and went quicker by a tenth. That's around 10 HP. I used the 68 setup because its much simpler than the 69. I would like to see what one of those scoops flow on a flow bench. I bet each one flows well over 400 cfm.

That could be strictly from the IATs dropping, and yes, flowing the scoops is what I was talking about. At 'over' 400 cfm each, it would have to be considerably over 400 cfm to not become a restriction.

I understand once psi starts to build with speed, they could flow more than a static 400cfm, but how much is the question.

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[HWYSTR455]

Originally Posted by Formulajones

Interesting question, I don't know. They seem to flow enough to support dads car fine with the 571 in it.

He ran the 69 setup up until he decided to install a Glasstek replica hood. No more flappers in the scoops. So I cut the scoops open, molded in an air box and use an L88 base, so it basically functions like the 68 version, and works excellent on his car.

How did you mold in the air box? Did you use an existing airbox and mod it? I'm interested. That would flow more than an OE setup IMO.

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[HWYSTR455]

Originally Posted by jhein

I still vote for a bigger cam. The RAII motors were designed to work with a 041 cam and a 400 cid, no? So if you have ported heads and 64 more cid I'd think it would be begging for a bigger cam.

Totally agree, though believe the cam has already been purchased.

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[HWYSTR455]

Originally Posted by Bruce Meyer

We can figure out how much they are flowing for your fathers cars needs. We can use a formula to find out how much HP he is making by knowing the ET. and weight of the car. Dyno #,s will work too if you have them. Once we know that we can calculate how much CFM is needed to make that HP and finally put this nonsense of the scoops being too small to rest.

That would show the amount of improvement over whatever the baseline flow is, but not if there is still more in it with more flow.

More I think about it, not sure data logging vacuum would show data required to determine if there's a restriction or not, but suspect it would be at least one data point.

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[HWYSTR455]

Originally Posted by Verdoro 68

The extra clearance King main bearings (MB5511XPSTDX) got here today, and I had the day off, so I spent the afternoon in the garage prepping the block and fiddling with the crank clearance.

The first thing I did was carefully clearance the block for the stroker crank counterweight. Tin Indian says they go for about .080, so that's what I did.





After that, I cleaned the block and went back to fitting the crank. The King bearings loosened things up exactly as advertised. I'm now on the tight side of the spec Butler provided for bearings 1-4, but the rear main cap seems to have much more clearance at .0034. I'm using ARP's torque recommendation for the studs w/ ultra torque lube - 110 ft/lbs on 1-4 and 140 ft/lbs on #5.

1: .0025
2: .0025
3: .0024
4: .0024
5: .0034

I double checked all the mains with plastigage, and they came out to within the ballpark I measured. The rear main looked a closer to .030 with the plastigage, but I trust my mic and the dial bore over it.

I put the Clevite back in and measured at .0015 - as it did the first time. I swapped shells back and forth and remeasured several times and got the same results. As a last resort, I measured the thickness of the shells and the King is .001 thinner than the Clevite (.0974 vs. .0984), that's probably where the .002 difference came from.

So I guess the question is, do I get a standard King set to see if I can get the #5 journal in line with the rest or roll with a looser journal?

With the mains all torqued down, the crank spins easily when you grab it by the snout. It's not a "two finger" spin like Cliff mentioned in an old post, but it takes very little effort. I couldn't even get the in-lbs it took to spin it to register on my digital torque wrench. No indication of tight spots from a few spins around.










Curious how you net out here. I could probably get away with that 236/242. I kept it conservative due to the A/C and power brakes. I also had my eye on making sure the retainers would't hammer the valve spring seals with a higher lift cam, like they did on my #16s. I could be wrong, but I think you can get away with more lift on the Edelbrocks?

Pretty sure the OE spec for #5 is a higher number than the rest, and believe the last 2 engines I had were at 30/32, and the one Olds engine was 35, none had any issues. But I would again suggest speaking to Butler.

As an example, a ran the equivalent to the road paver in a car with PB & AC, no problems, at around 12-13" vacuum at idle. Granted, I did run a dual diaphragm 8" booster, but just to give an idea. Again, granted, that was with E-heads, but you could check, and adjust for the higher lift.

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[HWYSTR455]

Originally Posted by 25stevem

If you just switched over to main studs without at least getting the main bore checked with a precision ground round checking rod or if not Aline honed then that’s why number 5 could be doing what your seeing.

Main studs pull on the blocks main Webb in a different way then do bolts!

Before you order up different bearings and if you still have the old rear main bolts, then I would install them and torque them up and see what might change with your bearing clearance.

Totally agree, and I always use at least main studs in all my builds. Cost is very low for the added insurance.

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[HWYSTR455]

Nice work by the way, and love the build!

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[Dragncar]

Originally Posted by HWYSTR455

That's more recent than I thought and after the PRWs were corrected, maybe the were old inventory? I know many use the PRWs with no issues, but for some reason I thought the issue was related to the wheel pin? I will go back thru my notes, but that will have to be after I'm done moving, living out of boxes right now.


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China rockers. Too many moving parts for comfort.

[HWYSTR455]

Originally Posted by Dragncar

China rockers. Too many moving parts for comfort.

Well, guess I will retract my blessing on those then. Regardless if others have been successful.

Always said Crowers are the only way to go, and that's all I use now. I just suck it up when comes to cost, and accept it's a cost required for a build.


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[Formulajones]

Originally Posted by HWYSTR455

I thought it was an article, maybe out of High Per Pontiac? Some reason I though maybe Rocky did the article, but can't recall at the moment.

Check vacuum, see if it starts pulling vacuum over x RPM. My understanding is it's a flow restriction, and don't disagree that IATs would drop.

I bet IATs drop even with an open element under the hood, as air starts flowing and evacuating from the underhood area, so think a comparison would be in order to determine the gains/improvements.

.

I don't recall the article. I played around with this on the GTO on my own along with 2 other cars (my Firebird and Chevelle) when we had them at the track.
I data logged KPA which was 101 for the entire pass, which basically equals zero. We did direct comparisons (same day) back when he had the 69 system on the car with an open element. That's why I stated the car always ran it's best times with the system in place and functional. After that I haven't bothered testing the open element theory on his car again now that I've reconfigured the ram air system to it's current setup.

Originally Posted by HWYSTR455

How did you mold in the air box? Did you use an existing airbox and mod it? I'm interested. That would flow more than an OE setup IMO.

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The air box is an OEM L88 setup that I molded in to enclose the scoops (turned 180), and uses a 14x3" filter inside. Just as GM did it on the vette. Just so happens that air box was about the right width to capture both scoops with a little modifying. Picture in post 27. It's basically working just like a 68 setup would, with the exception the filter is housed in the hood rather than the air cleaner base, but once the hood is shut, it's the same thing.
But the restriction still comes from trying to suck all that air in through the 2 little scoop openings. That's really where everyone feels the restriction is. Also generally accepted that since the scoops only stick up about an inch above the hood and being in the middle of the hood doesn't get the scoops out of the boundary layer and aren't very effective, not the best design. But, they seem to work.

As far as the OP's car is concerned, I'm of the mindset that muscle cars have really cool hoods, and even cooler when they are functional. It just makes the car to me. Since he's running the RAII heads on the car and a RAIV intake, it just seems appropriate to put the RA hood setup on the car to go with it all. Being a 68 Goat, it's such a clean and simple RA setup too that looks worlds better than the giant enclosed single snorkel air cleaner that 68's had, and more sophisticated and more classy than just plopping a generic open element air filter on top of an expensive engine if you know what I mean.

[Stan Weiss]

Originally Posted by Formulajones

I don't recall the article. I played around with this on the GTO on my own along with 2 other cars (my Firebird and Chevelle) when we had them at the track.
I data logged KPA which was 101 for the entire pass, which basically equals zero. We did direct comparisons (same day) back when he had the 69 system on the car with an open element. That's why I stated the car always ran it's best times with the system in place and functional. After that I haven't bothered testing the open element theory on his car again now that I've reconfigured the ram air system to it's current setup.

The Ram Air effect increases with MPH. The formula I have shows around .3 psi increase at 130 MPH which is only about a 2.07 KPA increase.

Stan

PS - Let me add those numbers are with a BP of 29.92. If you are racing at a lower BP those numbers / increases will be lower.

[25stevem]

The scoops on the 68 to 70 hoods and even the 65 to 67 hoods do not provide a pressure gain above atmospheric that’s worth even talking about if my two cents is worth anything!

Its more informative to look at temperature drop that they can provide by means of wind chill.

Now the hood scoops on the 71 GTO way at the front of the hood are far better at pressurizing the carb!

[TCSGTO]

Originally Posted by 25stevem

The scoops on the 68 to 70 hoods and even the 65 to 67 hoods do not provide a pressure gain above atmospheric that’s worth even talking about if my two cents is worth anything!

Its more informative to look at temperature drop that they can provide by means of wind chill.

Now the hood scoops on the 71 GTO way at the front of the hood are far better at pressurizing the carb!

Yes, they are at the boundary layer and don’t really “ram” anything. I kept the open scoops but ditched the pan when the car started getting well into the 11’s. Up till then it did seem to help a little on the street on hot days but you cool your engine down between passes anyway at the track.The scoops got to be a restriction at higher power levels.
FWIW keeping the fuel cool is probably worth more power than cooling the air. Cool fuel pulls more heat out of the intake tract than air. The old 1% increase in HP per 10 degree temp drop rule of thumb has been disproven many times. There is an improvement but not that much.

[Skip Fix]

For 3" mains King does have a 0.001 tighter set also.

[android 211]

Jim Hand found the cast iron intake was worth 10hp over the RA/HO aluminum intake. The repros aren't as good as the originals either. And the '68 RA II had an iron intake. Very cool setup overall. Will the air conditioning be revived?

[Stan Weiss]

Originally Posted by TCSGTO

Yes, they are at the boundary layer and don’t really “ram” anything. I kept the open scoops but ditched the pan when the car started getting well into the 11’s. Up till then it did seem to help a little on the street on hot days but you cool your engine down between passes anyway at the track.The scoops got to be a restriction at higher power levels.
FWIW keeping the fuel cool is probably worth more power than cooling the air. Cool fuel pulls more heat out of the intake tract than air. The old 1% increase in HP per 10 degree temp drop rule of thumb has been disproven many times. There is an improvement but not that much.

Interesting. If you look at how the dyno correction factor is calculated you will see that SAE 607 (which is used by most engine dynos) works out to just about 1% per 10 degrees,

Stan

[grandam1979]

That would be cool ram air II with a/c then that cam you got will be perfect. Actually I would use it if you already have it either way. If your not chasing e.t.’s at the track and you drive it a lot you will like the cam you have. My 2¢

[Verdoro 68]

Originally Posted by 25stevem

If you just switched over to main studs without at least getting the main bore checked with a precision ground round checking rod or if not Aline honed then that’s why number 5 could be doing what your seeing.

Main studs pull on the blocks main Webb in a different way then do bolts!

Before you order up different bearings and if you still have the old rear main bolts, then I would install them and torque them up and see what might change with your bearing clearance.

During the last rebuild is when I switched to studs, it was align honed then. I don't think I have the original bolts, but that would be an interesting experiment.

Originally Posted by HWYSTR455

Pretty sure the OE spec for #5 is a higher number than the rest, and believe the last 2 engines I had were at 30/32, and the one Olds engine was 35, none had any issues. But I would again suggest speaking to Butler.

Good to know!

Just ran into a snag with the bearings if I need another set. I sized the clearances using King XP and the standard size are out of stock until late October. Butler sells the HP line. I'll give Butler a call after the holiday.

Sounds like the consensus across the board is to ditch the PRW rockers. That opens up the 1.5 or 1.65 question again. I'll have to see what the heads are clearanced for when I get them back.

Regarding the cam, I'm already two roller cams into this build since I upped the cubes from a 400. I'll use what I have and see how I like it. This isn't a track car, just looking for something good and torquey to cruise around with and put my foot into every now and then.

[Formulajones]

Originally Posted by 25stevem

The scoops on the 68 to 70 hoods and even the 65 to 67 hoods do not provide a pressure gain above atmospheric that’s worth even talking about if my two cents is worth anything!

Its more informative to look at temperature drop that they can provide by means of wind chill.

Now the hood scoops on the 71 GTO way at the front of the hood are far better at pressurizing the carb!

I never claimed it as a pressure gain or meant that it had any ram air affect, other than that term just being used as a general reference, that's all.

The fact remains that having those scoops functional on dad's car has proven to be worth a bit of ET and has always run it's fastest time, with numerous engine combos in the car, with the scoops open and sealed to the carb.

The part that I found most interesting was the question that Bruce brought up, since now those 2 little scoops are the only thing feeding the 571 that makes 724hp, and it hasn't seemed to kill any performance. So how much CFM actually gets through those openings?

I did however mention how those scoops are poorly positioned right in the boundary layer. My 70 Formula works the best out of the bunch from what I've experimented with, and the Z and Chevelle both grabbing at the base of the windshield work exceptionally well.

I'm still of the mindset that the OP's setup would look killer with the 68 system intact and functional. He likes period correct making the car appear as if he would have built it in 69-70 using over the counter OEM performance parts, as he mentioned in an earlier post, and to me the 68 RA pan setup is at the top of that list.