[2wheeler]

I'm in the budget of finding a used set of heads for my '81 chevy shortbox daily driver but I was thinking about bracket racing it this year... looking around in the local rag I can only find three sets of heads for sale and almost anything would be better than the smoggers that are on it now. Just looking for opinions, I'm assuming the first pair are the best...

$400- ported and polished 350 heads 1.94 ss intake, 1.50 exhaust valves. Screw in studs and guide plates. Shaved, camaro .600 lift dual valve springs

$300- 041 heads, magnafluxed and decked. They have new seats and guides. All they need are 1.94/1.50 valves to go in

$200- 350 open chamber heads with 2.02 intake, 1.60 exhaust valves. High performance valve job, and shaved aprox. 100 miles on them.

[65smallblock]

The 400.00 set doesnt give enough info to make a good judgment. They could be anything from excellent to boat anchors. Ive got a set of "Camaro 350" heads with all those other goodies and I use them as a step to reach my top shelf.

041's are good. The "open chamber" heads are just like what youve already got.

Im a bit curious about the 305 heads. Im seeing threads on the webb comparing them (when ported) to vortec heads. Do they really have that much potential?? Anyone??

[GMC boogie]

041's would be the best choice based on the information you provided.

[2wheeler]

65smallblock- I have experienced 305 heads on a 350 and it gives you torque off the line power but they're equivalent to smoggers in the rpm range... It's a bear to reach 4,000 and your pulling hair to ever hit 4,500...
I wouldn't mind hitting 5,000 no problem.

The open chambers are definitly out of the question then, what are a couple of questions that I could ask to find the potential of the p/p 350 heads? So far it sounds like the 041s are the way to go... thanks for the insite.

[oldbogie]

Originally Posted by 2wheeler

I'm in the budget of finding a used set of heads for my '81 chevy shortbox daily driver but I was thinking about bracket racing it this year... looking around in the local rag I can only find three sets of heads for sale and almost anything would be better than the smoggers that are on it now. Just looking for opinions, I'm assuming the first pair are the best...

$400- ported and polished 350 heads 1.94 ss intake, 1.50 exhaust valves. Screw in studs and guide plates. Shaved, camaro .600 lift dual valve springs

$300- 041 heads, magnafluxed and decked. They have new seats and guides. All they need are 1.94/1.50 valves to go in

$200- 350 open chamber heads with 2.02 intake, 1.60 exhaust valves. High performance valve job, and shaved aprox. 100 miles on them.

The old story here is that when it comes to horsepower for the buck, you've got to go a long ways and spend a lot of money and effort to equal the Vortec head. Out of the box they're worth a 20 to 60 horsepower increase before your touch them with a die grinder. The amount of power they will provide is dependent on the engine's state of tune. 20 hp being more common to a lower compression, milder cammed engines and 40 aligns to engine's with more compression and cam timing that are capable of more revs than milder engines.

They do limit the lift at the valve to about .47 inch without modification to the upper valve guide and improved valve springs. Socggin-Dickey sells the P/N 125508060 head either OEM or modified for more lift at reasonable prices, not much more than you'd pay for a decent set of preped older heads. GM offers a couple race ready versions, part number 25534421 and more the 25534431. The 060 requires a unique intake that matches the tall port configuration and bolt pattern of the original L-31 Vortec. The latter 2 part numbers while more expensive will use more common intakes in terms of port height and bolt pattern. These heads are tough to beat either in cost or on the track.

One of the problems you have with the old engine is that GM trimmed the compression ratio with piston that uses a circular dish in the crown. One of the big issues, low compression aside, is that these pistons do not make full use of the squish/quench characteristics of any cylinder head and especially modern heads like the Vortec. This results in an engine that is rather detonation prone for the compression ratio. Replacing the pistons with those of a D-dish design do a lot to improve squish and quench which is a considerable asset in keeping detonation minimized for any head, but it really lets you push the Vortec types up into the 9's without difficulty. The other trick is to keep the piston crown to the head's squish/quench deck around .045 to .060 inch. When you assume Chevrolet's usual .025 inch clearance to the deck and a .020 inch shim to a .035 inch multilayer gasket, one arrives at the these clearances pretty quickly. Certainly with a .025 deck, a .053 inch thick gasket is already started into the excessive clearance direction. However, Vortec heads will take about 10ccs out of your current chamber size which will raise your current static compression by close to a full ratio, into the range of 9 to one or more. At this point even if you don't change pistons, the Vortec's improved mixture swirl, faster burn chamber, and better, though not ideal in your case, squish/quench will tolerate this compression.

Folks have put stock into modified 305 heads for many years to get performance somewhat comparable to older (pre 1973) closed chamber performance heads. 65Smallblock was looking at and wonder about the many bloggers claiming success with this. It is possible to make a pretty decent set of heads out these, especially by mid-1970s thru mid 1990s standards, but they just don't produce on par with Vortec/Fastburn heads, more like the L-98 head which ain't bad but a pair of out of the box Vortecs will smoke 'em
by an easy 40 ponies and will smoke older open chambers by 60 before you even start grinding on 'em. In fact the risk to Vortecs/Fastburns is that it's really easy to take the die grinder and cause them to flow less than they did out of the box. Ya got to have a fair idea of what your doing when you put a cutter to these modern heads.

Bogie

[cool rockin daddy]

I have the 041's on my small block. Good head. However, I am counting the days until I can put some GM Bowtie Vortec 180 heads on it. An easy 30-40 HP upgrade. You won't spend that much more for 'em than you would the 041's after you get valves and install them.

[ScoTFrenzel]

Originally Posted by cool rockin daddy

I have the 041's on my small block. Good head. However, I am counting the days until I can put some GM Bowtie Vortec 180 heads on it. An easy 30-40 HP upgrade. You won't spend that much more for 'em than you would the 041's after you get valves and install them.

The EngineQuest 180 Vortec head is better than the GM.
EQ is an iron replacement head the circle track guys use.

[GMC boogie]

In case you did not know....Cool rocking daddy is talking about the GM BOWTIE Vortec head. A very much improved version of the production "062" head.

I have used one set of EQ "IMCA" heads they produce for class rule dirt racers that have depleted the early 70's large chamber heads.

I have not seen thier Vortec version. They have a quality product but I doubt it's better than the Bowtie Vortec.

If you know something I don't.....please elaborate on your statement.

[F-BIRD'88]

I have run both vortec heads and fully ported big valve 305 heads on the same 350 in the same car.
I'm not going to say the modified 305 heads are exactly the same or just as good, but they certainly are comparable in performance. Very strong well past 6000 rpm.

Stock OEM 062 vortecs flow 228cfm. My ported 305 heads flow 234cfm.
The key word here is fully ported. If you just do a little, expect a little. They flow about 188 in stock OEM form.

The L-31 vortec heads work really good. Fully ported 305 heads work suprizingly good.

Both are light years ahead of stock smogger heads on a 350.

I'd go for the 041 heads. These work very good to0 especially with some porting.

[2wheeler]

Okay so I got the casting numbers of the first set of heads and they're 462624... Does that change anything? The machinist also said they are about 68cc. 624s or 041s??

[F-BIRD'88]

No question there. Of the two choices the 041's a clear better choice.

[ap72]

Originally Posted by F-BIRD'88

I have run both vortec heads and fully ported big valve 305 heads on the same 350 in the same car.
I'm not going to say the modified 305 heads are exactly the same or just as good, but they certainly are comparable in performance. Very strong well past 6000 rpm.

Stock OEM 062 vortecs flow 228cfm. My ported 305 heads flow 234cfm.
The key word here is fully ported. If you just do a little, expect a little. They flow about 188 in stock OEM form.

The L-31 vortec heads work really good. Fully ported 305 heads work suprizingly good.

Both are light years ahead of stock smogger heads on a 350.

I'd go for the 041 heads. These work very good to0 especially with some porting.

When I start clearing off current projects I want to do the 305 head thing. Not for any particular reason, just to expieriment I like to see how far you can push stock parts. I'll probably tune it for ethanol as long as it lasts at the pumps. With gas falling its questionable, even in the midwest. There was a time when you didn't have an affordable aftermarket and hot street cars were all running ported factory castings.

[65smallblock]

Originally Posted by 2wheeler

65smallblock- I have experienced 305 heads on a 350 and it gives you torque off the line power but they're equivalent to smoggers in the rpm range... It's a bear to reach 4,000 and your pulling hair to ever hit 4,500...

Sounds to me like what you had on that 350 was maybe a set of swirl port heads. ?? I think that they were put on 305's and 350's and once in a while some schmucks try to pass them (swirlie) off as Vortecs. The ones Im talking about dont have the swirl ports, Im specificaly looking @ a set of 416 heads.

F-bird, how would you rate a set of ported 305 heads vs a set of old fuelies? Sounds like they would flow about as well.

[F-BIRD'88]

The "old fuelies" refering to the 63 65 327 corvette 461X head with large 170cc ports and 2.02's flows 214 cfm in stock origional OEM form. Of course they flow a lot more than that in full ported form. 260+cfm. (full effort)

On a typical street/strip 350 a "fuelie head" with some port and chamber work that gets the flow up to 230 cfm to 250 ish works very well.

The stock 041's (1.94 valve) flow right around 195cfm in origional form.
They port up real well. Nice HP head.

[65smallblock]

Originally Posted by 2wheeler

Okay so I got the casting numbers of the first set of heads and they're 462624... Does that change anything? The machinist also said they are about 68cc. 624s or 041s??

According to Mortec the 462624 has 76cc chambers. They are probably just like tha 882 heads Ive got, all show and no go. I call them oxymoron heads. Id steer clear of those ones.

I think Id probly steer clear of that "machinist" as well. He would clearly put lipstick on a pig to try to sell it @ an inflated price.