I'm putting them on my .030 over 350 with flat tops. Any idea of my CR?
What if i had stock-style dish pistons?

 

What's the deck clearance? What cc's valve reliefs?

Depending on the deck clearance, could be anywhere from 9¼:1 to almost 10½:1, depending on other parts details.

Those older heads lack several features in regard to how they run, that are necessary for a modern motor: hardened seats so that the valves won't eat their way through the head due to lack of lubrication that used to be provided by leaded fuel, and the "squish" area under the spark plug, that allows about a half point higher CR than what those heads will allow.

On modern fuel, about the highest CR I'd DARE to try to run with those heads, would be around 9¼:1. And even then, it would be premium ONLY.

I hope you're not intending to put those in any car that's been built any time since the early 70s..... since in addition to their incompatibility with modern fuel, they're also not compatible with little minor details you might want to include in your car, like, an alternator for example. Which, in addition to their otherwise general obsolescence, is probably why you got them so cheep or even free: they weren't of any use to the last person who had them, either.

 

is it possible its a typo and you ment 416's? or are you on the pipe?

 

If they don't have the 3 bolt holes on the front of the heads, then they won't be too much good to you without spending ALOT of money on goofy aftermarket brackets designed just to make those fossilized heads work. And even then, they are only decent heads now - a set of plentiful and very cheap 416 or 601 heads will perform as well or better than those heads, and will have the necessary 'modifications' for use on modern engines/fuel - like hardened valve seats, the accessory holes on the ends for your alternator and power steering pump mounts, etc.

461 heads had 62-64cc chambers, the 416 have 58-60cc chambers, and the 601 have 53-56cc chambers. 416 came on most cars and light trucks with 305 engines before 87, and the 601 came on light and medium trucks with 262 and 305 engines in the early 80s.

The 601 heads have the best design for a high performance build - they have the best chamber design mainly. The 461 and 416 both have a very similar chamber design which is a pretty decent one, but the 601 chamber design is about a half-way design between the 416 chamber and the modern LT1/Vortec heart shaped chambers. I used a set of 601 heads with 1.94/1.6 valves on my 350 with flat tops that had around 11.25:1 CR and it was torquey like you would not beleive. The low/mid-range torque and throttle response was incredible - much better than my new 64cc/200cc World heads feel, though the top-end of the 200cc is obviously much better.

Anyway, find a set of 601 or 416 heads (or Vortecs if you are buying an intake too) and use those - will make your life so much easier.

 

the bolt holes are not a problem for me. I ordered the March kit that totally mounts off the water pump. In fact i have all that bolted up. I hope to drop the engine in the car soon. I was just wondering about the CR that these would create on a stock deck block with stock style dish pistons in a .030 overbore. Thank you sofa for answering my question.

 

I guess the holes are a moot point then. The 461 heads' chambers will vary from 62-66cc.

If you look up "compression ratio calculator" on Google, you'll find several calculators that will just have you punch in numbers and give you an accurate answer, rather than us just giving you a rough estimate.

What do you mean by 'stock type' dished pistons? There are ones with valve reliefs only (about 6cc "dish"), a smaller dish like the L98 had (around 12cc dish) and the monster smog-era dished pistons (around 16cc dish).

You'll also need to know how deep the piston is in the bore (if you know the pin height on the piston, you can figure this out) and how thick your head gasket is. Generally, stock is pistons are .025" below the deck, but that can change depending on if the block decks were shaved, and what pistons you are using.

What you'll need to know for most calulators:

- Bore size
- Stroke
- Chamber CC's
- Piston dish CC's
- Deck clearance (how deep the piston is in the bore)
- Head gasket compressed thickness

 

how much was the pully setup out of curiosity? were these heads free or just something you already had?

 

I have 462's on mine. You will need lead substitute (available at every Walmart). Don't miss a fillup with it. If your block was a budget build and has not been zero decked your C/R will not be too high for premium (or maybe even midgrade) IF it has enough cam to lower the DCR. Close to correct quench height is important (which means don't try to lower the c/r with a thick gasket).
In the mid-late 70's we put those heads on stock 350's with steel shim gaskets and it would turn a 9.5/1 regular engine into a premium fuel engine with about 30+ hp increase. Same cam, stock intake, and everything. Just a head swap with used heads. That's why you heard good things about those heads.
Don't let the naysayers get you down. Have some fun. A lot of people can't stand the fact that you can make more than 350 HP without spending $1000 on heads .

 

i got them from a friend of mine, he went with zz4 heads. the setup was 250 from march. I Ordered individual brackets from 3 different kits.

So is it neccesary to run the lead substitute? is it for Valvetrain lubrication?
What happens if i don't?

 

The valve seats on the early heads were not hardened, they used the lead in the gas to lubricate the valve/seat contact.
If lead substitute is not used rapid wear of the seats will occur.
If the heads have exhaust seat inserts installed by a machine shop(rare) then it won't be needed.

 

Yeah, I used to do that too, because that was when those older heads started getting REAL cheap, because they wouldn't fit on current-model cars.... until I found that the newer double-humps, the ones WITH the bolt holes like the 186 and 041 and 492, with their better combustion chamber design, ran WAY WAY better than the old ones, even if the car didn't need the bolt holes. Like on old 60s Chevelles or Novas or something.

No you don't "have to" spend $1000 on heads to have fun, or to exceed 350 HP. All you need is the RIGHT stock castings. Doesn't bother me a bit to run stock castings, in fact I have a pair of 186s on my car right now. But 461s aren't the best recipe for "fun" in 2007, either.

 

oooo, I'm tellllin' !!!
Speaking of the 461's, do you think grinding the sparkplug side "de-quench" would make the chamber the same as 462 and newer (old) heads; changing it from 57cc to 62-63cc
Not talking about the runners, just the chambers.
(I know... it's easier to start with newer than '65 heads)

 

I've never tried it; but it does seem like it would help.

Generally relieving the "edge" of the chamber on the side oppposite the plug to where it's not so much of a "bathtub" but rather more of a "pool" helps, I DO know. Unfortunately that also adds a couple of cc to the chamber.

 

I just picked up a set of these heads as well. When I calculated it up with my flat tops, in my 350, 0.060" over I came up with ~10.5:1

 

I'm running a set of worked over 041's right now, actually I've been running em for about 6 years.. gottem years ago for $75, decent for the money, defently not the best thing out there though..