Nostalgia Superstock 67 Fairlane

[KeiserMustang]

The alternator bracket set-up..your own design/fabrication or sourced through a vendor?

I designed the alternator mounts and made them when I still worked in the machine shop.

[KeiserMustang]

I'm kind of surprised that those springs won't handle that cam, especially with titanium retainers.  I think I'd try shimming them, maybe go to a 1.95" installed height using -.050" locks, assuming you have the room over the valve seal.  Alternatively, maybe a Pacalloy spring that's a step up...

My machinist and dyno operator is not convinced the springs are the problem either.  He seems to thing the motor is just running out of power up top and the sudden drop at the end of the pull is just a result of where we have the dyno set to brake.  It's a Superflow 901.  I don't honestly know how that works, but I thought we made a pull up to 7200 rpm and it still hit a ceiling at 6700 and dropped suddenly.

The valves are still 3/8" stem, maybe heavy?

The Comp 955 springs are Pacalloy.

Went ahead and ordered a set of -.050" locks.

[jayb]

Well, I can guarantee you that no motor runs out of power and drops off that suddenly.  A dyno curve should look smooth, not discontinuous like yours does.  Something is happening at that point in the RPM range.  Also, if the dyno settings were off the motor would not behave that way either.  I have a Superflow 901, and it is possible to squeeze off the power of the engine at the top end if you have the valving at the absorber set wrong, but it would have to be set WAY wrong, and it wouldn't cause a sharp drop in power like the one shown in your chart. 

One other possible cause might be an ignition issue.  Is that possible?

If you install those -.050" locks, will you take it back to the dyno to run it again?  It would be interesting to see if increasing the spring pressure helps the problem...

[blykins]

Compression ratio?

[fe66comet]

What heads are those? Just wondering for comparison, I upgraded my heads to 11/32 undercut stems and bigger valves. I am going to stay lower in the RPM range though and have smaller cubes.

[KeiserMustang]

Well, I can guarantee you that no motor runs out of power and drops off that suddenly.  A dyno curve should look smooth, not discontinuous like yours does.  Something is happening at that point in the RPM range.  Also, if the dyno settings were off the motor would not behave that way either.  I have a Superflow 901, and it is possible to squeeze off the power of the engine at the top end if you have the valving at the absorber set wrong, but it would have to be set WAY wrong, and it wouldn't cause a sharp drop in power like the one shown in your chart. 

One other possible cause might be an ignition issue.  Is that possible?

If you install those -.050" locks, will you take it back to the dyno to run it again?  It would be interesting to see if increasing the spring pressure helps the problem...

Absolutely, the engine is still on the dyno now, so as soon as I get the locks changed, we'll run it again.  I'd also like to run it up about another 500 rpm or maybe around 7300 to see if the HP curve rolls over smoothly like I think it should.

Ignition on the dyno is a very old 7AL.  Probably worth looking at.  Also, the MSD distributor in the motor is at least 14 years old.  We thought about changing the pickup as well, but I don't know if that's something that could cause a high RPM problem, or if bad is just bad and it won't run?

I'll be sure and post the results.  Hopefully on Saturday.

[KeiserMustang]

Compression ratio?

Somewhere around 13.5:1

[KeiserMustang]

What heads are those? Just wondering for comparison, I upgraded my heads to 11/32 undercut stems and bigger valves. I am going to stay lower in the RPM range though and have smaller cubes.

Edelbrock heads...

[fe66comet]

I thought so but was not sure, I have the RPM heads also. I am surprised you got that much power out of them but with 13:1 that explains a lot. I am shooting for 11.5:1 myself. Very interesting build for mostly off the shelf stuff and not a lot of fancy goodies. Can't wait to see how it pans out for you.

[KeiserMustang]

I thought so but was not sure, I have the RPM heads also. I am surprised you got that much power out of them but with 13:1 that explains a lot. I am shooting for 11.5:1 myself. Very interesting build for mostly off the shelf stuff and not a lot of fancy goodies. Can't wait to see how it pans out for you.

Hmmm...I sure wouldn't consider anything on this engine "off the shelf"...LOL 
There's not a single part that hasn't been cut, ground, machined, ported, polished, whittled, worked over, fitted, pulled apart, reworked, re-fitted and reassembled! 

Custom pistons, custom cam grind, custom pushrods, untold hours in the heads for bigger valves, intake ports "moved", chambers massaged, machined for T&D competition rocker system, intake reworked...

[fe66comet]

Port work excluded of course, I have the same rocker system. I went with the T&D race myself as it seemed the nicest system to me and I like the through rod oiling. The port work on my heads still need to be completed, along with chamber reshaping and I am looking for someone to port my intake right now.  I would do the intake lower myself but i am shooting for somewhere between 340-350 CFM intake wise @.700 lift.  The intake manifold will be the big question at this point as to how much I can squeeze out of it. I wonder how much you could have gained with a valve change and undercut stems? It looks like you lopped a lot out of the intake manifold so that certainly helped feed the beast , what was you final port size on the intake manifold? I suppose if all else fails for my plan I could do some welding to make my port work? Welding aluminum is not my forte so I would have to farm that out LOL.

[ScotiaFE]

Now the big
                 

How many pedals?

[KeiserMustang]

Now the big
                 

How many pedals?

Just two for now...
Adding the third pedal is REALLY expensive 
But it is part of the plan...someday.

[blykins]

Did you measure port velocity? 

[KeiserMustang]

Did you measure port velocity?

We did measure the flow numbers on the flow bench, but to be honest I'm not sure I've heard of measuring port velocity.  How is that done and what does it tell you in comparison to flow?