The Stovebolt Site Forums The Shop Area The HiPo Shop 2.02 or 1.94 heads ?

I am looking at a 1968 327 to put in the old truck.Trying to decide if it has 202 or 194 heads. It has the double hump casting marks a lowrise castiron manifold with a qjet. the damper pulley is not bolted to the crank. My guess is a 300 hp 327 with the 194 heads. my buddy hopes it is a 202 head so we can put a bigger cam in it and get the hp up.Any way to tell with out pulling the head? Thanks for any thoughts.

Check here: http://outintheshop.com/faq/casting/heads.html

Look at the casting Numbers, 461 were 1.94, however there are 461 heads out there that have 2.02 valves. Lots of heads were rebuilt and people went to the 2.02 valves. You do not need 2.02 valves to put a bigger cam in the engine.
The 1.94 heads will perform well enough with a larger cam in the engine. For some reason beyond my comprehension, People think that you have to have big valves for performance. You don't need those for a street engine.
Unless you are constantly running your engine at 5,000 RPM, you won't see any significant change in the performance of the engine with the larger valves. A word to the wise, some of the early heads did not have a port for the water temp. sender, If you have heads like that, be sure to get an intake manifold that allows for the temp sensor.

I concur...I have a '66 327 (275hp) with 461 'double hump' heads, and they have 1.94 intake valves. Yours could have been modified, of course, so the only way to know for sure is to remove a head and look/measure. With 2.02 intakes, you can't hardly get a fingernail in between the valves.

cm

After many hours of dyno testing and a few thousand miles on a circle track, I'm of the opinion that the only time the 2.02" intake is an advantage is on an engine that's going to see a lot of full-throttle operation above 6K RPM or more. I prefer to use the 1.94" intakes, combined with a 1.6" exhaust valve and some pocket porting under both valves. The only time the extra intake size is needed is on a race-only engine that doesn't need any low end or midrange performance.
Jerry

I don't know, HRL. Sounds like an un-researched, good ole boy, Git-R-Done approach. Maybe you should forget about a lifetime of real world experience and consider studying this issue to death before you spew potential disinformation such as this.
I'm sure that there are bloggers out there somewhere who can steer you in the right direction.
Carl

The BEST advice I can give you concerning ALL small block Chevrolet engines is to calculate your volumetric efficiency and make sure you get as much air coming in as you get going out. Too many people I have known in the past that guess, or just want what they want on their small block Chevy engines over cam and over carb the capabilities of the engine, resulting in an engine that runs way too rich or way too lean and not within a RPM range suited for the street. In other words, the BEST scenario is they are not satisfied with the performance of the engine and at the WORST, the engine just runs like garbage. There is a mathematical equation that can give you the answers needed for the best volumetric efficiency for your application.

Tim

Double hump heads sound nice, but so much more can be done with aftermarket heads. I'd run the 1.94 intakes and wouldn't sweat it.

I made quite a few bucks turning 76CC 350 Chevy low compression heads into 60CC "cheaters" for the round track guys to use on their claimer engines. A .100" angle mill job gave the heads enough compression to be competitive and they still had the right casting number to get past the tech inspectors. Along with a 1.94/1.6 intake/exhaust valve job, they were at least as effective as the expensive and illegal double hump heads. Very few tech inspectors had even a suspicion of what was going on.
Jerry

One thing the factory equipped 2.02" heads had that most back yard shops didn't do when they installed larger valves was a chamber that was unshrouded to help the larger intake valve breathe. Installing a 2.02" in most small chamber heads that aren't relieved won't really provide any benefit. And unless you open up the bowl accordingly for the larger valve, it won't help much either even if you unshroud the chamber.

A pocket porting job was part of building the cheater heads I used to produce. They definitely wouldn't pass an engine teardown, but very few competitors wanted to pony up the money for that kind of protest.
Jerry

Its not cheating if you don't get caught.
Nor post it on the internet...

Carl,

I think what I just read and understood from Jerry was that IF someone were to do something like what he was talking about, most inspectors probably wouldn't check, allowing you to get away with a more then most people would think.

Did i read it correctly?

Chris

Since I'm not building race engines anymore, I can share a few tricks of the trade. The one I really liked was being able to turn an engine 1500 RPM faster than the competition on a restricted-size carburetor, and nobody could figure out why. The question I usually asked my customers was "Do you want it legal, or fast?"

That particular engine was built 100 cubic inches smaller than the one everybody else was running, and that made a Holley 7448 350 CFM carb do things it just wasn't supposed to do. When the 350's we were running against were turning 6200 RPM, mine was turning 8,000. Every casting number that was visible during a tech inspection indicated it was a 305. The short stroke crankshaft that made it a 255 cubic inch wasn't technically "legal" for the class we were running, but the casting number was buried way down in the crankcase. LOL!
Jerry

The lack of this kind of creative engineering in today's racing is exactly why I no longer follow racing. That, and there are too many pretty boys behind the wheels. I want a driver who is fully capable and somewhat likely to rip someone's head off when the need arises. When Danica Patrick is the "toughest" hombre after a race, you have a problem.
Carl

When a few of us dirt trackers from Merced California used to convoy up to Antioch for the end-of-season big money 100-lap race, we would pit together, and watch each other's backs. Since we usually had slightly faster cars than the locals and won most of the money, we had to run against the other drivers, the fans, and the officials. It was pretty much a combat zone!

Dirt tracking is fun- - - -NASCAR is boring!
Jerry