Within Stock rules???

Originally Posted by Rick Leininger Jr.

Then why do all the newer combos (COPO, Cobra Jet, Drag Pak) go quicker when "gone through"?

So modified heads are the only way to make power? The engines are not sold completely blueprinted it is still a manufactured product. it's made like that so owners/engine builders can finish the engine anyway they see fit within the rules. Same thing that has been happening since the early 60's

There is no other way to improve a combo? Tuning, testing ect? Just do the heads and let it rip?

[Rick Leininger Jr.]

Originally Posted by Todd Hoven

So modified heads are the only way to make power? The engines are not sold completely blueprinted it is still a manufactured product. it's made like that so owners/engine builders can finish the engine anyway they see fit within the rules. Same thing that has been happening since the early 60's

There is no other way to improve a combo? Tuning, testing ect? Just do the heads and let it rip?

I never mentioned heads, or any other part(s). You said "These cars were build in a max effort capacity to begin with by a company that has every resource." and "The engines are not sold completely blueprinted it is still a manufactured product. it's made like that so owners/engine builders can finish the engine anyway they see fit within the rules."

Which is it?

[Billy Nees]

Originally Posted by Rick Leininger Jr.

Which is it?

That kinda depends on which side of the rules you want to walk on, doesn't it?

[Rick Leininger Jr.]

Originally Posted by Billy Nees

That kinda depends on which side of the rules you want to walk on, doesn't it?

Not necessarily, I think max effort and the performance that comes with it is possible without crossing any lines regarding rules, but that's just my definition.

Originally Posted by Rick Leininger Jr.

I never mentioned heads, or any other part(s). You said "These cars were build in a max effort capacity to begin with by a company that has every resource." and "The engines are not sold completely blueprinted it is still a manufactured product. it's made like that so owners/engine builders can finish the engine anyway they see fit within the rules."

Which is it?

I mean head design, materials used like Ti valves and retainers. Cranks, rods, and other special parts.

I guess is what I'm trying to say is that the CNC program that is used to profile the heads I'm sure has been researched and pretty close to the best you can buy. IMHO.

I think unless you have spent time with one of these engines you don't realize how good the parts are that used in these engines.

[camaroagogo]

These cars are all certainly "stock eliminators"!!

[Rick Leininger Jr.]

Originally Posted by Todd Hoven

I mean head design, materials used like Ti valves and retainers. Cranks, rods, and other special parts.

I guess is what I'm trying to say is that the CNC program that is used to profile the heads I'm sure has been researched and pretty close to the best you can buy. IMHO.

I think unless you have spent time with one of these engines you don't realize how good the parts are that used in these engines.

I've seen inside a few, whether good parts/execution were used is likely a matter of opinion, to each their own.

[Dwight Southerland]

For purely philosophical considerations, consider the following points.

• For a car-engine combination to be raced in NHRA “Stock” eliminator, they make the rules. Generally, it is assumed that the car has to be built by a manufacturer that is recognized by NHRA and that the specifications for the car and engine are provided to and accepted by the NHRA tech department. It is also assumed that eligible combinations are manufactured in sufficient quantity and available to the general public so that it fits some definition of being a “production” car. These assumptions are leftovers from the origins of the “Stock” category in the 1950s when the only cars were sold at dealerships and it was obvious what a “stock” car was and what it was not. Even then, however, there was some controversy with such models as the 1953-54 Hudson Jet with the Hornet twin-carb engine, the 1953 Buick Riviera, the 1957 Pontiac Bonneville with fuel injection, the 1955 Studebaker President Speedster and others. Fast forward to today’s selections and some of our purist assumptions simply don’t count. They make the rules and there is no external standard or prevailing authority to stand in judgment of what they say. All the decisions are made within the hallowed walls of NHRA and there is no scrutiny or oversight. Even looking at the “traditional” set of cars to be raced, there are enough exceptions, anomalies, and contradictions to show that the actual rule is “whatever that’s in the tech bulletins and class guides is what is legal”.
• Imagine you are racing Stock eliminator in the late 1970s. Out of the blue, Chevrolet decides to spec a production engine that is basically a Modified Production engine – 315 cu in, aluminum rods, ported cast iron heads, titanium valves, stud girdle, triple valve springs, roller camshaft, max compression ratio, 750 Holley carb on a single plane manifold – and stuff into a Monza car that has fiberglass fenders, hood and doors, a Dana 60 with ladder bars, a Doug Nash 5-speed transmission and back-halved with formed frame rails to fit 9x30 tires. Chevrolet says they are going to build 100 of them and sell them through their dealer network rated at 300 horsepower. Ford soon follows suit with a Pinto or Mustang II similarly equipped and then MoPar tops that with a race Hemi in a Colt or Arrow. Sound familiar?? Do you think that NHRA would have accepted those cars back then? Sure they would!! What’s the difference with that and what was allowed in the 1963-1969 era? And they even accepted a car with ported heads and had no specs for them (1969 SS/C AMX). Today is another one of those eras with the factory cars. Time and effort will force all these exceptions together, just as they have over the years.
• So, is that COPO engine legal with its max block, ported heads, etc. etc. etc.? If NHRA says so, it is. You may not like it when you struggle to pass tech with your traditional stocker, but they make the rules.
• It is surprising to see the righteous response to machining intake (or exhaust) surfaces of the heads to reduce the port volume so they can pass tech. That practice has been going on since the first days of recorded port volumes. That is the basis of the standards applied to the SS/AH engines and the requirement to not machine past the valve cover studs. Heck, when Chevrolet re-released the 291 cast iron BB head in the late 1980s, the exhaust ports in the new heads were too large for the current spec so before somebody petitioned to get the spec changed we would machine the exhaust surface back to meet the specs (and angle mill to reduce the length of the port roof!).

[Billy Nees]

Great post Dwight! You're the man!

[Brian4992]

The School built this engine 100% to the rules as we interpreted them. This specific engine was torn down at the 2015 Chevrolet Performance US Nationals. The engine passed tech. The tech guys did a very thorough job including;
intake port
exhaust port
chamber
valve head and stem size
bore and stroke
deck
gasket thickness
cam lift
lifter plunger travel
intake manifold and throttle body

-Brian