Aren't those heads gonna be quite the choke point with no port work on 427 cubes?

 

I'll guess 425/475. But I am just guessing.

 

The last 9 to 1 stroker build with the same heads and a smaller roller cam made over 400 hp and 500 ft/lbs. I say 435 hp/535 ft/lbs. The other one made great vacuum, curious how much that will drop. Also 10 to 1 is pushing it with iron heads, curious how it will run on 91 or will 93 be manditory?

 

 

Following closely.

Few questions. Valve sizes. 2.000 and 1.625. Why? Out of interest, since my head builder, for exact same 7a's chose that valve size. Didnt want 2.07 intakes and DEFINITEDLY NOT 1.68 exhausts. Ill trust him on this, as he has decades of experience solely from building heads. And were not building all-out race-heads. Interested because the norm here ( web) seems to be to stuff largest valves you can physically fit.

Im reaching 10:1 compression also, but instead i chose carbs but with fully programmable ignition with vacuum sensor to fight against detonation.

My quess.. 455/520

 

 

 

The owner has a clear reason for the conservative combination. His 16 year old will be driving it, at least for now.
Then he can replace the heads, cam etc once that scenario changes,

 

 

That's a lot of power! Impressive Mark.

 

What issues did you have? A lot of people make these sound like a miracle product

 

What do you guys have for pump premium, 91 octane or 93? What quench do you run on your motors? Awesome power by the way.

 

They're not, but remember this is a Terminator, not a Sniper. It uses a regular HP ECU.
It wouldn't learn as programmed and the onboard O2 is off significantly. When I did pulls based on the HP O2, it was struggling and registered a 14.5:1 afr on the dyno O2, but showed 13.5 on the HP software. However I was commanding 12.7, problem. It made 446 on that pull.
So I turned everything off, self learn, closed loop etc., and built a fuel map myself that targeted mid 12's for air/fuel. It made 487 so it's safe to say I was headed in the right direction. However the HP software showed that it barely got above 10.0:1. I'm discussing this with Holley but haven't found the issue yet.
None of these self learn systems are perfect, I've been saying that for years.
Christian - 93, squish was about .048-.050 on this build.

 

Drool. And this is with iron heads! Here I was thinking alum heads would be necessary to eclipse 450 HP in a SBO. The owner should be overjoyed with these results. Great job, I need to get off my rear and begin planning my build.

 

Congrats Mark ! That is outstanding and hope to do one your kits in a couple years for one of my cars