305 chevy heads; 081 castings vs 416 castings

In this video I try to compare two different types of stock chevy 305 heads. I have a set of 081 castings and a set of 416 castings. I do my best to compare the intake ports and the combustion chambers. I also go over the other differences between the two.

[@whitewolf30f]

In 1995, the hot tip was a pair of 1976 305 heads, the only year they were heavy casted. Those coukd be cut for 1.94/1.60" valves, no problem. I did it myself. But now, just get a pair of L31 heads shaved 0.030" and do all you can fir exhaust flow.

[@MasterWitchDoctor]

and with a 1.94 inch intake valve they flow less than a 1.84. Those heads had a 1.72 inch intake and tiny intake ports that flowed about as well and straw trying to suck up an icee.

[@RustyNutsGarage]

Nice explanation of both heads. I didn't know the differences. I have set of 081's that I will port and put on a 327 this winter. I think I have the better heads over the 416s.

[@davidcraft4909]

Thanks for watching.

[@johnkelly8525]

Don't do it man , you have a 4 inch bore you can do so much better

[@MasterWitchDoctor]

305 heads on a 350 is a bad idea, the 081 heads shut off @ .500 lift and the chambers are so small your compression ratio will be so high it wont run on pump gas. If you want a good flowing street head get a pair of 113 corvette aluminum heads.

[@MasterWitchDoctor]

I have an 87 Monte Carlo SS I raced in NHRA Stock Eliminator K/SA (K Stock Automatic) and I have the option of using a 535 casting, 416 casting, and 081 casting. With a 3 angle valve job a 416 casting is hard pressed to hit 180 cfm @ .403 lift which is what a stock L69 cam has. With a 3 angle valve job the 081 flows 197 cfm at the same .403 lift which is actually better than every double hump head with a 1.94 inch intake valve @ .400 lift. Stock eliminator is limited to the stock cam lift which is .403 intake .415 exhaust. Both heads being equal the 081 outflow every other non vortec 305 by a lot and every 1.94 inch 350 head with the exception of the 113 corvette aluminum heads. If the other heads flowed better I'd be using them. And as far as the earlier smog castings (555, 434, 450, etc...) had 1.72 inch intake valves and are in no way shape or form a performance head. The chambers suck, the port suck, and theyre about 15 lbs heavier which in racing is a bad idea. Opening up the valve seat and putting a 1.94 inch intake valve in these heads will actually flow less than a 1.84 inch if you do not port them. Randy Brzezinski (Brzezinski Racing) has a whole video on this for those who are non believers. The intake ports on an 081 are 167cc whereas a 416 is 162. The exhaust ports are identical in cc's and flow numbers which is in the 119 cfm range with a 3 angle valve job. I wouldnt waste any money on these heads other than installing screw in studs and DO NOT ever use a roller tip rocker arms, they do ZERO for performance. Either use a full roller or a stock rocker, the roller tip rocker arms are waste of money.

[@keithbevins2989]

The roller tip rockers do help with valve guide wear.

[@davidcraft4909]

I never really thought about that, but I believe it. I always wanted roller tip because it's supposed reduce friction. But that's probably a better reason to buy them.

[@MasterWitchDoctor]

@@keithbevins2989 so does synthetic oil, its the fulcrum that matters not the tip where it presses on the valve.

[@scottshumaker4969]

What size engine you putting these heads on ? I have 416's going on a 1971 307 chevy.

[@davidcraft4909]

They are going on a 305.

[@MasterWitchDoctor]

everything being equal a 307 with its bigger bore and shorter stroke will beat a 305 in horsepower by a lot. Ive seen 307s making 325 hp all day long and the 305 heads only had a 3 angle valve job screw in studs crane springs and it had a retro fit hydraulic roller cam.

[@deanmoody1434]

58 cc’s - old style and TBI heads- vertical planning and horizontal planning- cfm flow’s better on the TBI heads, and yes they were resurfaced about .002 thousand’s on the 55 cc heads

[@itseithergonnaworkoritaint7852]

Are you sure those aren't 305 TPI heads? The TBI heads are the swirl port heads.

[@MasterWitchDoctor]

@@itseithergonnaworkoritaint7852 081s where used on the 87 and 88 305 LG4 tuned port.

[@StrokerB]

Do you rebuild engines?

[@davidcraft4909]

I have rebuilt a few, but only older chevy engines.

[@lordsauto]

Are the 081 heads for the roller block

[@davidcraft4909]

I'm not sure yet. I would rather use the 081s, but it kind of depends on which set needs the least amount of work and which set would make the best compression ratio with flat top pistons.

[@accessgainer8]

It can be used on either block.

[@MasterWitchDoctor]

@@davidcraft4909 the 87 L69 305 used flat top pistons and a .016 thick steel head gasket. I use the factory stock gaskets in my 305 which makes 11:1 static compression which is NHRA rules.

[@davidcraft4909]

@MasterWitchDoctor I was just about to ask you what compression your car has, and the next question is what kind of cam. I'm just trying to get a little bit of info on what works.

[@MasterWitchDoctor]

@@davidcraft4909 the factory L69 305 came with 9.5:1 compression. NHRA measures compression in static compression not dynamic compression because static is exact whereas dynamic compression varies. NHRA allows for 11:1 static compression and my cam is a custom ground Crane solid lifter with .018 clearance on the intake .022 on the exhaust. A 305 is responsive to a cam a lot more than a 350 because of the smaller bore size so if youre wanting advice on a cam id keep the intake duration 224 or less and lift is effected by the heads ability to flow. Most stock heads (305 especially) wont flow much better after .450 lift because of port saturation and a higher lift cam creats parasitic stress on the crank and it starts to lose horsepower. My suggestion would be a Crane 215 intake 225 exhaust .450 / .460 lift. assuming your 305 has a 1.84 inch intake you need a cam with a lobe center angle of 109 degrees according to David Vizards 128 rule. That formula is 128 - (CID / Number of Cylinders / Valve Size x .91) = Lobe Center Angle. In your case this is 128 - (305 / 8 / 1.84 x .91 = 18.85) = 109.44. My solid lifter cam is also 109 degrees so I know for a fact this number is dead on.

[@dillinpicklesworth5698]

416 is 58ish 081 is 56ish from factory No real flow difference, But 416 can be worked better because better strength in casting, up sizing valve won't increase flow much but cleaning up roof and entry helps, 416s have been a junkyard gem for rules class dirt track engines, H.O. heads prone to cracking like vortec heads, 416 flows as good as standard 350 heads but add good compression, the box around the plug on 081 heads create a hot spot prone to pre ignition and needs to be rounded on the corners if installed on 350, hope this helps, 👍

[@davidcraft4909]

Any information helps thanks for commenting. I'm building a 305 with flat tops. I was leaning towards using the 416 heads just because I have a few intakes for the older style. But the valves are looser in the 416s and probably need valve guides. The 081s are noticeably tighter so I will use them instead. People were using 305 heads on 350s to bump up the compression 20 years ago. I'm not a big fan of doing that but it will make a soup bowl piston 350 wake up a little bit.

[@andrewfortier88]

Last year I built a low mile 305 standard bore. Installed flat tops mild port job and 3 angle valve job on the 416 heads summit 1103 cam and knock off rpm intake with performer 600cfm carb. Sounds mean at idle makes decent power and runs on cheap 87 octane gas. Well worth it if its just laying around.

[@davidcraft4909]

@andrewfortier88 I will definitely take a look at that cam. Because I really don't have any knowledge or experience on what would be a good cam for a 305. I was actually thinking about using a stock lt-1 cam since I can get a used one for free. I'm not really sure if that's a good cam, but I'm looking into that. Thanks for watching and commenting.

[@andrewfortier88]

@@davidcraft4909 it is a mild cam in a 350 but in a 305 with 10:1 compression it really runs nice, starts easy has a nice chop good throttle response and pulls good to 5500 rpm. If I was to make an honest guess I'd say 275+hp. Stock hp is like 160

[@andrewfortier88]

@@davidcraft4909 Lt1 would be a roller cam I've only ever built a flat tappet. I always take the old cam out and toss it in the scrap pile. Plenty of cheap cam kits out there to suit your build.