[ZeGermanHam]

Came across a new video (posted 7/17/2020) detailing the build and dyno test of a 389 bored & stroked to 461 and using Autotrend 3x2 EFI setup. Pontiac engine builds so rarely come up on YouTube that I thought you all might enjoy viewing.

Video: https://youtu.be/-VjXNjo71SY

[1965gp]

Cool vid. Interesting how the throttle bodies bolt to the intake!

[shaker455]

I liked the vid but I was not impressed with dyno performance.
Either way nice build and happy to see a Pontiac get some attention.

[Scott65]

^Agreed
Really expensive modest performance

[steve25]

Not at all impressed with the level of power the motor made even putting the big cost of the new parts aside!

This also puts in into clear perspective how purely stupid it is to run after market big port volume Round port heads as many people do with a stock iron tripower set up that is more restrictive then the one in the video no less!

If you care to look for the info from HPP mag, Jim Taylor some years ago built a up iron tripower 440 street motor with ported iron 389/ 421 heads which flowed all of 218 peak Intake cfm and that motor made over 450 hp, in fact it may have been a peak of 475 hp I just can't recall , infact the motor made 350 hp just running on the center 2bbl!

So yes I am not impressed at all, in the least!!

[charlie66]

They didn't mention if they had to open up the push rod hole for the 1.65.

Nice build. I guess that intake was the reason for the lower power ..

[Murf]

Yeah, it sure was a mixed up combination. I wonder what the intake was costing them in output.

Most people used to stress that it was unwise to compare numbers from different dynamometers. Is that no longer true?

Murf


Sent from my iPhone using Tapatalk Pro

[slowbird]

Originally Posted by steve25

Not at all impressed with the level of power the motor made even putting the big cost of the new parts aside!

This also puts in into clear perspective how purely stupid it is to run after market big port volume Round port heads as many people do with a stock iron tripower set up that is more restrictive then the one in the video no less!

If you care to look for the info from HPP mag, Jim Taylor some years ago built a up iron tripower 440 street motor with ported iron 389/ 421 heads which flowed all of 218 peak Intake cfm and that motor made over 450 hp, in fact it may have been a peak of 475 hp I just can't recall , infact the motor made 350 hp just running on the center 2bbl!

So yes I am not impressed at all, in the least!!

Aftermarket heads and stock tri-power (just port matched) work just fine. You statement saying it's stupid is stupid.

[Jay S]

Thanks for sharing the link for the video.

That looked $$$$$$$$$$!!!!!!. Plus the owner lost all the main caps and they did all billets. Yikes!

Curious how they came up with the “modest 9.8 scr compression? Flat top pistons, 72 cc e head 4.155x4.25. That should be 11+? Even with a 87 cc E’s and the flat tops it would difficult to get it below 10:1.

[steve25]

Working and getting the most bang for your dollars invested are two completely different things, you can't see that?

[slowbird]

Originally Posted by steve25

Working and getting the most bang for your dollars invested are two completely different things, you can't see that?

You made a general blanket statement saying it's stupid to put a tri-power on e-heads. I said that statement is stupid.
We ran mid-low 10s with stock '65 tri-power e-heads and hft cam weighing 3450lbs seemed to work. We also picked up half sec going from well port iron heads to the e-heads. So from our testing/experience e-heads and tri-power work well together.

[Formulajones]

Originally Posted by Jay S

Thanks for sharing the link for the video.

That looked $$$$$$$$$$!!!!!!. Plus the owner lost all the main caps and they did all billets. Yikes!

Curious how they came up with the “modest 9.8 scr compression? Flat top pistons, 72 cc e head 4.155x4.25. That should be 11+? Even with a 87 cc E’s and the flat tops it would difficult to get it below 10:1.

I was wondering that too.

[Formulajones]

Originally Posted by Murf

Yeah, it sure was a mixed up combination. I wonder what the intake was costing them in output.

Most people used to stress that it was unwise to compare numbers from different dynamometers. Is that no longer true?

Murf


Sent from my iPhone using Tapatalk Pro

For the most part....yeah. Something I learned from Paul, I don't really trust any dyno numbers posted on a forum or on you tube unless they provide the BSFC and lbs per hour so you can figure out the % correction factor used and see if it's reasonable. Because they can basically make it what ever they want. Ever see a dyno sheet that just has HP and TQ listed but all the other columns are zeros?? Those are the fishy dyno sheets, lol.

This one however doesn't appear to be inflated for the sake of notoriety though.

[Formulajones]

I do like that EFI tri-power setup. Pretty cool.

[Murf]

Yeah, I thought it was pretty cool too.
It’s hard to know what the owner was wanting to do.
I wonder if maybe he was wanting the “cool” factor but could step it up with just an intake change when he wanted to.

Thanks for the info on dyno numbers Formulajones!

Murf


Sent from my iPhone using Tapatalk Pro

[Formulajones]

You're more than welcome Murf! Stay safe up there, hope to see ya again soon, maybe with a car this time

[Steve C.]

During a dyno session the first thing Steve Brule at Westech Performance looks at is the BSFC numbers !

Jim McFarland explains brake-specific fuel consumption (BSFC) and how it impacts the thermal efficiency of a racing engine ...

https://www.hotrod.com/articles/ctrp...l-consumption/



.

[Murf]

Originally Posted by Formulajones

You're more than welcome Murf! Stay safe up there, hope to see ya again soon, maybe with a car this time

We’ve been talking about. IDK, that’s a long haul for us. I was thinking maybe you’d drive up to Great Bend in the fall.

It was great meet you guys& man that weather is awesome!

Hey, I sent you a PM.

Murf


Sent from my iPhone using Tapatalk Pro

[ZeGermanHam]

Originally Posted by Murf

Yeah, I thought it was pretty cool too.
It’s hard to know what the owner was wanting to do.
I wonder if maybe he was wanting the “cool” factor but could step it up with just an intake change when he wanted to.

I think the owner is just going for underhood visual appeal, since the engine is going into a '55 Safari wagon show car with skinny whitewall tires. Perhaps not an optimal combination of parts, but he'll for sure have too much power for the car as it is.

[ponjohn]

It says 416 in the print portion of the video. I'd be ok with that power if it was a 416 - 461- nah.