[lust4speed]

Our Inland Empire GTO Club had its dyno day a few weeks ago, and I thought I'd share how my blue goat did. Total of 13 Pontiac's ran on the chassis dyno and my 670 iron headed 1967 GTO came in second in horsepower and first in highest torque at the rear wheels out of all the cars. It came in above 3 of the aluminum headed engines (2 Kaufman and 1 Edelbrock). All my runs were made through the mufflers and half the runs were made with the stock air cleaner in place on the Quadrajet carburetor. While the numbers show that there's more to the engine than what you can see, I did pull it back out of the garage last weekend and drove it 227 miles to the Midnight At The Oasis show in Yuma, AZ. It managed 14.3 MPG on the way to the show but a strong headwind on the way home cut the mileage to 12.4 MPG. The mileage around Yuma on the poker run and Friday cruise was a low 7.8 MPG, but I did a lot of irrational driving that the Yuma PD would have frowned upon had they seen it.

My son Mark's '65 2+2 was 5th overall behind two aluminum head engines but in front of the remainder of the iron heads. His 421 came in at 362.8 HP and 500.3 Torque at the rear wheels on a 12 year old build with a Crower 60919 cam and Rhoads V-Max lifters.

Here's a quick rundown of our results:

Owner..Horsepower..Torque.......CI & Notes
Tim.........510.8.........517.4..........468 open header Kaufman 310's, solid roller cam
Mick.......450.5.........527.1..........462 mufflers 670 heads
Bill..........445.5.........465.6.........468 mufflers Kaufman 305's
Tom........400.8.........465.8.........462 mufflers Kaufman 305's
Mark......362.8.........500.3.........437 open header 62 heads
Bruce.....340.9.........370.7.........442 open header 96 heads
Jimmy....306.1..........387.3........400 mufflers 670 heads
Rick W....316.2.........372.6........468 mufflers round port Edel carb problems
Mark P....311.5.........363.4........462 open header 96 heads
Rick H.....247.9.........317.7........406 muffler 16 heads
Larry S....239.5.........333.3........400 mufflers 670 heads
Dan........183.4.........259.4........400 mufflers carb problems
Glin........151.5.........198.6........326 mufflers

[hal101]

WOW that is great

[lust4speed]

My car was rather anti-climatic on the dyno and just lifted up and made the pull, but Mark's car had probably the best attitude of any car out there that day. Here's the double pull of his car. His engine is only 9.1:1 compression. Mark's Pull

[steve25]

Great job with those iron 670 heads Mick, real sweet!

What would have shown even how good the iron heads are for motors of under 425 cid would have been if any of the 400 cid motors in your dyno day test had aluminum heads on them of over 200 CCs in port volume.

Unless your building a 400 cid or less, true all out race motor then cylinder heads of over 205 CCs of port volume will be found to be counter productive in your quest for the best average power numbers!

The factory had a total grasp on what size port was needed for max average power up to 5400 rpm, hence even with the 455 SD motor they went with 180 CCs of port volume.

I guess the lessons 1969 of the RAV heads on the 400 motors was still leaving a bad taste in there mouth even in 73 ,and rightfully so!

[Cliff R]

It's all about the combination and tuning. You can get it done with iron or aluminum heads but for sure it makes you feel better about your engine combo when it's using traditional parts like iron heads, factory carb/intake/distributor etc.

That's one of the main reasons I went back to a factory intake to sit under my factory carburetor. It goes better with the stock valve covers, HEI, and stock air clean and Shaker assembly. After you make a pass at the track folks are nearly in shock when they wonder by to take a gander at what you're using and see the stock appearance.

Anyhow, nice job for sure and excellent numbers from the engine combination.......Cliff

[PAUL K]

That's cool! Would you have track times for your car or any of the others?

[scott70]

Nice dyno #'s!! I like to see iron heads prove themselves. Is it a lean condition or excessive fuel that creates all the popping and banging when you let off the throttle? Out of all the open headered race cars Ive had I think I only had one that would do that at the end of the track when you let off the gas/..

[Half-Inch Stud]

Good to see a spread of data.

Were open-exhausts cars " opened-up to open headers for the test?

[Firebob]

Really good numbers for a chassis Dyno. They usually seem kind of deflating ( to your ego ) on paper because of the drivetrain loss. Or maybe it's just me.

[Lee]

Great data, thanks for sharing!

13 different Pontiacs, variety of heads, CID variance of 142 inches, and EVERY one of them made more torque than HP, yet nearly every build thread has something to the effect of, "I want ??? horsepower." If their cars weigh about the same and have equal traction, I'd love to see Mark and Tom race.

[Chief of the 60's]

What fuel?

[ta man]

Pretty cool! I like the assortment of engines.

[ta man]

Originally Posted by Lee

Great data, thanks for sharing!

13 different Pontiacs, variety of heads, CID variance of 142 inches, and EVERY one of them made more torque than HP, yet nearly every build thread has something to the effect of, "I want ??? horsepower." If their cars weigh about the same and have equal traction, I'd love to see Mark and Tom race.

Take all the cars to a dragstrip and compare!

[77 TRASHCAN]

I hope Jim Hand is reading this!!!

[wbnapier]

May I ask where you went in the IE to do the dyno? I'm close by and would like to have the info for future reference.

[ponyakr]

Originally Posted by ta man

Take all the cars to a dragstrip and compare!

The Stock Stock & SS racers have been making big power with iron heads for a long time. LOTS of 10 sec Stockers. And that's with low lift non-roller cams, near stock stroke cranks, heavy pistons, iron intake, & Q-jet. Randi Lyn Shipp's '67 Bird is the 1st that comes to mind. I think she's run in the 10.40's. And that's with 670 heads, a '67 iron intake, & a 750cfm Q-jet.

http://www.classracerinfo.com/Engine...4&MAKE=Pontiac

https://www.dragracecentral.com/DRCS...r2017#indextop

Also some 9 sec SS cars, with iron heads. The Burton 400 powered GT 3rd gen, from 2017, comes to mind. Greg Meyer also has a quick 400 powered GT car. Both these cars run low 10's . Not positive if both cars have dipped into the 9's or not. Maybe somebody knows. If round port iron heads count, that adds several 10 sec Stockers & 9 sec SS cars. Leo Glasbrenner, Scott Burton, Brad Burton, Keri Angeles Pari, and JB Clegg, come to mind. Norman Warling posted that Scott made a high 9 sec run with his Stocker, if I remember correctly.

Seems like I remember somebody posting a chart showing aprox how much hp it takes to run a certain 1/4 mile speed.

http://www.wallaceracing.com/hpcalculatorquarter.php

["QUICK-SILVER"]

Originally Posted by scott70

Nice dyno #'s!! I like to see iron heads prove themselves.

Neat as can be.

Originally Posted by scott70

Is it a lean condition or excessive fuel that creates all the popping and banging when you let off the throttle? Out of all the open headered race cars Ive had I think I only had one that would do that at the end of the track when you let off the gas/..

That would be from excess fuel air mix getting lit off in the pipes. Shutting throttle blades at WOT (backing off) runs intake vacuum up 2~3 times what idle circuit is adjusted for. Fuel mix gets too rich to burn and gets dumped in the exhaust. When cylinders do fire off it ignites the unspent mix in the exhaust.
The closer throttle blades are to shut, at idle position, the richer the mixture gets while backing off. That's why some do more backfiring than others.
Lots of factory carbs had a dashpot that kept throttle blades from snapping shut. It kept the throttle blades partially cracked and bled down slowly to the idle position. Saved fuel and kept mufflers from blowing up.

Clay

[Jim Moshier]

Mick,
WOW, that is impressive numbers! with iron heads or Aluminum sounds like you have a nice combination and 14 mpg is pretty good as well. Mark compression in 9.1 to 1 what is yours and do they both use premium 91 octane. Thanks for sharing

Jim

[ta man]

Originally Posted by ponyakr

The Stock Stock & SS racers have been making big power with iron heads for a long time. LOTS of 10 sec Stockers. And that's with low lift non-roller cams, near stock stroke cranks, heavy pistons, iron intake, & Q-jet. Randi Lyn Shipp's '67 Bird is the 1st that comes to mind. I think she's run in the 10.40's. And that's with 670 heads, a '67 iron intake, & a 750cfm Q-jet.

http://www.classracerinfo.com/Engine...4&MAKE=Pontiac

https://www.dragracecentral.com/DRCS...r2017#indextop

Also some 9 sec SS cars, with iron heads. The Burton 400 powered GT 3rd gen, from 2017, comes to mind. Greg Meyer also has a quick 400 powered GT car. Both these cars run low 10's . Not positive if both cars have dipped into the 9's or not. Maybe somebody knows. If round port iron heads count, that adds several 10 sec Stockers & 9 sec SS cars. Leo Glasbrenner, Scott Burton, Brad Burton, Keri Angeles Pari, and JB Clegg, come to mind. Norman Warling posted that Scott made a high 9 sec run with his Stocker, if I remember correctly.

Seems like I remember somebody posting a chart showing aprox how much hp it takes to run a certain 1/4 mile speed.

http://www.wallaceracing.com/hpcalculatorquarter.php

Basically what I meant was this was a dyno comparision. A fun club day suggestion would be a "track day". To see if the guys with the better power to weight ratios can out run the others or will some of the lesser powered cars surprise.

[lust4speed]

Originally Posted by PAUL K

That's cool! Would you have track times for your car or any of the others?

I raced the blue goat for years until I finished up the dedicated drag car. The flimsy Muncie and 10-bolt rear went back in the blue goat at that time so I try and behave myself in it. I broke my self imposed rule and took it to the strip last year and stripped out the cone clutches on the first pass, and didn't get a time. All the cars at the dyno session are street cars and all run on our goofy 91 octane CA gas. Tim with his 66 GTO ran 11.22 on first pass in Arizona and had to slow it down to keep from getting booted from Pontiac Heaven in 2016. It would have run faster on later passes but we had to take out a bunch of timing and he had to short shift at 4,500 to get it over 11.50's. Son Mark in his 65 2+2 ran a corrected 12.88 in a Pontiac Shootout article with a race weight of 4,480 and a smaller cam a few years ago. Bill B. with his 69 GTO runs 11.80's. Bruce R. with his 67 GTO runs 12.5's and Mark P. with his 67 GTO clone runs 12.6's.

Were open-exhausts cars " opened-up to open headers for the test?

Most that had headers were. Both my car and Bill B.'s have Doug's headers but were run through the mufflers. Most that could run uncorked did so as noted.

Really good numbers for a chassis Dyno. They usually seem kind of deflating ( to your ego ) on paper because of the drivetrain loss. Or maybe it's just me.

Seems like most use a 20% driveline loss percentage. I usually use 15% for a manual car like my blue goat.

May I ask where you went in the IE to do the dyno? I'm close by and would like to have the info for future reference.

We were very happy with Josh at JEP located in Hemet, CA. He gave us a great club price and supplied his big barbeque and we fed everyone all they could eat hamburgers, hotdogs, and chips. Some other places like Westech charge too much to try and put on a club dyno day. Then we have others that are just too flaky to trust running our cars. Josh is the owner and was very safety conscience and ran a tight ship all day.

What fuel?

Everything that day was on pump 91 octane.

Take all the cars to a dragstrip and compare!

We actually have a really high percentage of club members that race, but a lot of us have progressed to dedicated strip cars. I raced the blue goat from 1989 to 2003 at all the Pontiac Drag Days races until I swapped out to the red drag GTO. The blue car back then would run high 11's and I'd have to slow it down to stay under the old 12.00 rollbar rule. This was the first time the club itself sponsored and paid for a dyno day. We go to shows, but many of us in the club would rather be drag racing than anything else. We do a pretty good job getting new members out to the track and getting their feet wet. We have members that belong to other Pontiac clubs, but are members with us also because we flog our cars like they were treated back in the day.

If their cars weigh about the same and have equal traction, I'd love to see Mark and Tom race.

Tom G. has a '65 GTO convertible with no roll bar so no track time, and my son Mark now runs the '68 Firebird at the track with rollbar in the low 11.30's with another set of 670 heads that are basically twins to the set on my blue car.

Mark compression in 9.1 to 1 what is yours and do they both use premium 91 octane. Thanks for sharing

Mine is 9.27 - was aiming for 9.3 and came pretty close on the final measurements. Tim's aluminum headed engine is 10.35, Tom's aluminum headed engine is 10.2, Bruce's 96 headed 428 engine is 9.2, and Rick W. engine with the round port Edelbrocks with the very small roller is 10.1 per his request.

After you make a pass at the track folks are nearly in shock when they wonder by to take a gander at what you're using and see the stock appearance.

Which is my reason for the correct heads, valve covers, intake manifold, and air cleaner. Nothing better than showing off the almost pure stock looking engine and whooping a$$. It could easily be faster with aluminum heads and open element air cleaner and other stuff, but definitely not as much fun. Even the dyno operator kept checking his stuff and ran my car a few extra pulls making sure what he was seeing was correct.

Anyway, first love is the dragstrip, but a day at the dyno can still be a great way to spend a Saturday. You get to hang out, tell lies, and it even feels like you can race a dyno by the end of the day...