[hurryinhoosier62]

Paul, what impresses me is the low end torque. 425 ft/lbs of torque @ 1800 rpm is fantastic! That's diesel numbers...

[gtofreek]

Actually, it was 425 @ 1600 RPM, it was 443 @ 1800 which is about what an original 400 did, only at 3200-3600 RPM's!

Did you see that reverse dyno pull down to 1300 RPM? I like that pull as you can really see how well the engine runs down low. Didn't try to hiccup or anything.

I love Harolds cams! They really work good, I don't care what anyone else says.

[hurryinhoosier62]

Yes, I did. VERY impressive engine. If my 3" main 421 turns out this good, I'll be elated!

[Chicagogoat]

There are too many things that this engine excels at like no other 400 I've seen! The fact that it runs fine on 91 octane @10.1:1 CR with iron heads is an outstanding accomplishment! The second amazing thing to me is the power and low end torque! Seeing is believing! I think this engine will destroy a lot of egos very soon! "It's just a 400 with iron heads, a mean cam, with a stock intake & Qjet"

[Boostedbird]

Nice engine Paul! I like the 400's and that it has some compression and runs on pump gas. I want to see it leaned out a touch with 4 tubes and a larger intake. I'm surprised that you didn't get the old " just because you didn't hear detonation , that doesn't mean that it's not happening."

[gtofreek]

Originally Posted by Chicagogoat

There are too many things that this engine excels at like no other 400 I've seen! The fact that it runs fine on 91 octane @10.1:1 CR with iron heads is an outstanding accomplishment! The second amazing thing to me is the power and low end torque! Seeing is believing! I think this engine will destroy a lot of egos very soon! "It's just a 400 with iron heads, a mean cam, with a stock intake & Qjet"

And don't forget the points distributor!

[gtofreek]

Originally Posted by Boostedbird

Nice engine Paul! I like the 400's and that it has some compression and runs on pump gas. I want to see it leaned out a touch with 4 tubes and a larger intake. I'm surprised that you didn't get the old " just because you didn't hear detonation , that doesn't mean that it's not happening."

We looked at the plugs which showed no signs of detonation. And the cam is advanced 6.75°! That just goes against what many preach around here, that you can't advance cams or they will build too much cylinder pressure, and detonate. It has more to do with valve positions at TDC, during overlap.

Plus, when my 428 used to detonate, it was a gutless wonder. Wouldn't get out of it's own way. I seriously doubt this engine would have made this kind of power if it was detonating.

[chiphead]

The reason I asked about the 110LSA, is that the slightly smaller Voodoo cam 219/227 is on a 112LSA. Made me wonder why? If I wanted to use the smaller cam, it appears to be much smaller for 1 step milder than the 231/239/110 used in this engine?

Would you need to advance the larger cam 6* degrees if it was on a 112"? Wouldn't it carry the powerband out further? What do I not understand?

[gtofreek]

Originally Posted by chiphead

The reason I asked about the 110LSA, is that the slightly smaller Voodoo cam 219/227 is on a 112LSA. Made me wonder why? If I wanted to use the smaller cam, it appears to be much smaller for 1 step milder than the 231/239/110 used in this engine?

Would you need to advance the larger cam 6* degrees if it was on a 112"? Wouldn't it carry the powerband out further? What do I not understand?

The smaller Voodoo's are on a 112° in order to get the in/ex lobe spacing more where they need to be on the smaller lobes. I would run that cam installed on a 106° ICL.

A 112° would carry the power band out further, but the 110° will carry it out to the limits of the lifters anyway, and it will make more power, so there is no need to go 112° on this. James said he didn't mind a little attitude with the cam, so we went this way.

[Will]

One thing I notice from the dyno sheet is this thing is running pretty rich in the 2000-3300 RPM range. I wonder if you could pump up the left side of that graph a bit by leaning it out to the 11.x:1 range and make it even more impressive... ;-)

I hope the owner has a good tire budget.

[chiphead]

The carb being rich is one thing helping to keep this engine out of detonation with 10:1 compression and 40* of timing! Those 670s are fuel hungry. Modern fast burn chambers may start to roll coal at 8:1 AFR. I imagine that if you leaned it out to about 11-12 AFR, it could start to pick up a few degrees of ping near peak torque. But yes, going to about 10.5 AFR in that region should be safe and may pick up a few ponies.

[gtofreek]

Originally Posted by Will

One thing I notice from the dyno sheet is this thing is running pretty rich in the 2000-3300 RPM range. I wonder if you could pump up the left side of that graph a bit by leaning it out to the 11.x:1 range and make it even more impressive... ;-)

I hope the owner has a good tire budget.

Yeah, I saw that but I'm not fully convinced his A/F meter was working right. The first run showed A/F ratios up around 126:1, then it would be 4:1 .2 seconds later. So we pulled plugs and looked at them, and the burn ring looked real good, so we didn't mess with it. Cliff built that carb for these engine specs, and it ran pretty flawlessly, and after reading the plugs, both the dyno operator[he has way more experience reading plugs than I do after more than 16,000 dyno pulls], and myself were convinced the carb needed no help.

[vidguy]

Originally Posted by Boostedbird

Nice engine Paul! I like the 400's and that it has some compression and runs on pump gas. I want to see it leaned out a touch with 4 tubes and a larger intake. I'm surprised that you didn't get the old " just because you didn't hear detonation , that doesn't mean that it's not happening."

I trust that Paul and the Dyno Operator were checking this, as I too was shocked that he ran it on 91 octane without Detonation.

Cliff told me that the carb was built a "little fat" as that is always the safe thing to do for break-in on a dyno. Rather have it a tad rich then start Pinging itself to death. He clearly had this just right and Paul's cam choice, install/timing complemented the carb and the heads.

I will however run 103 octane gas in this or at least a mix of 103 and 91.

Now I'm thinking I may need a RobbMc powersurge to keep the fuel coming. Again, I'm trying to run this as Original. That includes the fuel and exhaust, (ram air manifolds). So I don't want to run new fuel lines but a powersurge may be acceptable as an add on.... I'll drive it and see if it noses over on hard acceleration..

Tires? Will, I have 15 year old Eagle ST's on it.. Clearly they'll have to GO before the second burnout...

[Will]

Originally Posted by chiphead

The carb being rich is one thing helping to keep this engine out of detonation with 10:1 compression and 40* of timing! Those 670s are fuel hungry. Modern fast burn chambers may start to roll coal at 8:1 AFR. I imagine that if you leaned it out to about 11-12 AFR, it could start to pick up a few degrees of ping near peak torque. But yes, going to about 10.5 AFR in that region should be safe and may pick up a few ponies.

Well, according to the chart it goes to the mid 12.x range by 3900-4000 RPM where the highest torque peak is, and that's about where I'd expect peak torque to be with a cam like this. True, it's making about the same torque down around 3000 with a much fatter AFR according to the chart, but if it's not pinging at 3900 at 12.4-12.7 I don't know why it would ping at 3000 at 11.5.

But, if what Paul says below is true and the AF ratio sensor is off then who knows what it actually was and it doesn't really matter anyway because it ran fine!

Originally Posted by gtofreek

Yeah, I saw that but I'm not fully convinced his A/F meter was working right. The first run showed A/F ratios up around 126:1, then it would be 4:1 .2 seconds later. So we pulled plugs and looked at them, and the burn ring looked real good, so we didn't mess with it. Cliff built that carb for these engine specs, and it ran pretty flawlessly, and after reading the plugs, both the dyno operator[he has way more experience reading plugs than I do after more than 16,000 dyno pulls], and myself were convinced the carb needed no help.

[vidguy]

It's been decided. We're gonna put the motor back on the dyno and do some comparisons!

Paul happened to get an SD ported intake in for another motor (probably the only one available in the country right now ) so he kindly offered to split the cost to do some testing. Here is what I'd like to do that Paul offered:

- A ported SD intake with my 750 Qjet. Same 91 octane gas (so that it is apples to apples)
- Paul's shops Holley on stock intake 91 octane gas
- A ported SD intake with Paul's shops Holley built by his buddy Jeff
- A Victor intake with Qjet
- A Victor intake with the Holley

I'm requesting that Paul run 101 or 103 octane for the last three tests.
Paul can you see if you can have the dyno's A/F gauge working correctly?

Paul, is this plan possible like we discussed?
Thanks for the offer Paul. I'm very interested in the results.

[bendutro]

Thank you guys so much for sharing this info. I have a set of RAIII heads that Dave B. ported to the same level as your 670s. I'm following this build closely. ;-)

[ta man]

Originally Posted by vidguy

It's been decided. We're gonna put the motor back on the dyno and do some comparisons!

Paul happened to get an SD ported intake in for another motor (probably the only one available in the country right now ) so he kindly offered to split the cost to do some testing. Here is what I'd like to do that Paul offered:

- A ported SD intake with my 750 Qjet. Same 91 octane gas (so that it is apples to apples)
- Paul's shops Holley on stock intake 91 octane gas
- A ported SD intake with Paul's shops Holley built by his buddy Jeff
- A Victor intake with Qjet
- A Victor intake with the Holley

I'm requesting that Paul run 101 or 103 octane for the last three tests.
Paul can you see if you can have the dyno's A/F gauge working correctly?

Paul, is this plan possible like we discussed?
Thanks for the offer Paul. I'm very interested in the results.

Be nice to find a ported torker 2 and a open spacer also for testing.

[pontibeast]

This is terrific info for others that can save a lot of wasted cash by having hard numbers to lay out a build plan with. Thank you all so much for doing the extra testing and also for sharing the data. This is what makes PY such a great forum, open sharing of info to help the Pontiac brand and cars stand out and improve.

[tom s]

AZ 91 I will bet is better than CA 91 gas!Tom

[vidguy]

Originally Posted by tom s

AZ 91 I will bet is better than CA 91 gas!Tom

Ha. Probably Tom.