Hot Rod Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
15,314 Posts
These are large open chamber, low compression SMOG head’s. They are low on compression and the chamber is a poor burner, which means you burn a lot of fuel for not nearly the power the engine could be developing. The head’s in configuration and the 1104 cam matches the GM 290 horse crate motor with a GM 4bbl intake and a Holley 650 CFM carb.

These head’s with .030 milled off and a .015 shim head gasket to get the compression up and with a mild port job of cleaning the pocket, streamlining the guide bosses and enlarging the runner to the paste line of the casting will dyno about 380 ft pounds at 3800 and 340 hp at 5400 with your cam and induction with long tube headers.

This same set up with L31 Vortec head’s will easily pull 30 more foot pounds and 40 to 50 more horsepower on the peaks with a longer flatter peak over more revs before decaying. The same power would be seen with aluminum import heads but aluminum brings issues of having to zero deck the block or run raised deck pistons to get the squish/quench clearance corrected. Which of course playing with the ports of L31’s or the imports offer more gains for the budget constrained builder. High end domestic head’s offer a lot more out of the box torque and power but certainly are not budget friendly.

These 487 head’s are sought after by class rule racers because as SMOG heads go these are the best of the worst. Bigger valves which Chevy stuffed some with are of little help as the ports really can’t feed them and the chamber burn is lazy slow and detonation prone. Raising the compression only makes the latter worse. Angle milling helps some but the complexity of this plus the weird angles cut on the intake to match it up to how the head sits is expensive and doesn’t on a dollars per horsepower gained prove that worthy of the effort and expense.

The cam your proposing is a step over stock stall converters so if you’re running an automatic your going to need to budget a higher stall converter of around 2500 to 3000 RPM’s.

What we know from experience is modern Ricardo (heart shaped) chambers bring a lot of action to the party that cannot be obtained from open chamber SMOG head’s.

Most aftermarket head makers also offer their wares in cast iron for a lot less cost than aluminum. These head’s are more robust than the L31’s.

Bogie
 

·
Registered
Joined
·
4 Posts
These are large open chamber, low compression SMOG head’s. They are low on compression and the chamber is a poor burner, which means you burn a lot of fuel for not nearly the power the engine could be developing. The head’s in configuration and the 1104 cam matches the GM 290 horse crate motor with a GM 4bbl intake and a Holley 650 CFM carb.

These head’s with .030 milled off and a .015 shim head gasket to get the compression up and with a mild port job of cleaning the pocket, streamlining the guide bosses and enlarging the runner to the paste line of the casting will dyno about 380 ft pounds at 3800 and 340 hp at 5400 with your cam and induction with long tube headers.

This same set up with L31 Vortec head’s will easily pull 30 more foot pounds and 40 to 50 more horsepower on the peaks with a longer flatter peak over more revs before decaying. The same power would be seen with aluminum import heads but aluminum brings issues of having to zero deck the block or run raised deck pistons to get the squish/quench clearance corrected. Which of course playing with the ports of L31’s or the imports offer more gains for the budget constrained builder. High end domestic head’s offer a lot more out of the box torque and power but certainly are not budget friendly.

These 487 head’s are sought after by class rule racers because as SMOG heads go these are the best of the worst. Bigger valves which Chevy stuffed some with are of little help as the ports really can’t feed them and the chamber burn is lazy slow and detonation prone. Raising the compression only makes the latter worse. Angle milling helps some but the complexity of this plus the weird angles cut on the intake to match it up to how the head sits is expensive and doesn’t on a dollars per horsepower gained prove that worthy of the effort and expense.

The cam your proposing is a step over stock stall converters so if you’re running an automatic your going to need to budget a higher stall converter of around 2500 to 3000 RPM’s.

What we know from experience is modern Ricardo (heart shaped) chambers bring a lot of action to the party that cannot be obtained from open chamber SMOG head’s.

Most aftermarket head makers also offer their wares in cast iron for a lot less cost than aluminum. These head’s are more robust than the L31’s.

Bogie
I can manage to get some 2.02, for 600.00, what do you think of the price, what should I offer? I had a pair of 2.02, developed a crack in each one, between the valves, #5 & #6 cylinders, my buddy added water, during spectator eliminators, #@%*ed me off! It ran great, I needed it once again, in the winter... short drive for advice on another chevy project
 

·
Registered
Joined
·
4 Posts
I can manage to get some 2.02, for 600.00, what do you think of the price, what should I offer? I had a pair of 2.02, developed a crack in each one, between the valves, #5 & #6 cylinders, my buddy added water, during spectator eliminators, #@%*ed me off! It ran great, I needed it once again, in the winter... short drive for advice on another chevy project
It was in a 70 Nova SS, I was working on a 76 Monte Carlo restoration.
 

·
Registered
Joined
·
15,314 Posts
Unless you need these for a numbers matching restoration or a specific race class that requires these by rule they are a complete waste, especially at 600 dollars. That kind of money will put you into a much better head whether that’s an L31, Vortec or something from the aftermarket.

There is no way to recommend these head’s for a performance build, they are physically weak and thus crack prone and are waaay down on power. A 2.02 intake on these head’s is totally meaningless. The ports even after porting just can’t feed the curtain area a larger valve provides and tge casting is not thick enough to port them to a size needed to feed that valve. Those head’s that came from GM with big valves were just a feel good exercise for the nonsense (especially for the understanding of these things in 1970) that ipso-facto big valves are bettter, this isn’t necessarily true.

Kindly reread what I originally wrote I’m not blowing smoke, I don’t care how much Brzezinski says about the miracles that can be performed on these head’s, unless your aimed at a specific stock racing class or you are building a numbers matching historic car, these head’s are best avoided. In that regard he’s always looking for cores of this head but I doubt he’s paying 600 dollars per pair.

Actually with modern head’s you can pull equivalent power to the cam your leaning toward with a smaller cam. This gets into dynamic compression ratio which is a measure of stroke used to the point where the intake is seated. Especially if you are running pump gas this is important as to the octane limits of modern fuels. The later in the compression stroke the intake is closed the more the stroke is reduced thus the engines working pressure thus its power. Modern design for power on the available fuel tends to as little duration as gets the job done and more lift. More lift demands more instant port flow in exchange for more open time from duration. The plan here is to conserve operating cylinder pressure and regain filling with more valve opening. These days with modern head’s and a more moderate duration cam building a 400 horse 350 is something you have to work against rather than for. This just drops out of modern chamber head’s, a tight squish/quench of .035 to .040 inch, a cam similar to Comps XE276H, an Edelbrock Performer RPM intake and a carb in the range of 650 to 750 cfm with long tube headers and you’ve got 400 hp on a 9.5 compression ratio. Very potent, very streetable and uses 89 to 93 octane fuel. From a 1960’s early 70’s perspective this is or was unheard of from the 11 to 1 compression of the day.

So yes you can get to big numbers with these 487 head’s but your going to have to put a lot of cam and compression in the motor and without a piston change you can’t get even to the point where the compression challenges 91-93 octane. It’s just a hard row to hoe with this historical stuff to get modern power. So it boils down to what you are doing in that is this a numbers matching museum piece, a class restricted racer, or a hot street build. If the latter I’d scrap the 487’s and go with a modern head whether aluminum or iron because that’s where the power is even with your old style cam choice there just is this large increase in torque and power just sitting there to be plucked with Ricardo chambered head’s within today’s fuel capped compression ratios.

My preference runs to aluminum head’s as they allow crazy high compression 10-11 to 1 because they move heat so fast. But even modern chambered iron do a great job on 9.5 to 1

Bogie
 

·
More for Less Racer
Joined
·
20,935 Posts
If the 487 heads need a rebuld, forget it, the cost isn't worth it. You can get new, better aftermarket for near what it costs to rebuild a old stock set anymore.

Same with those $600 2.02's you mentioned, if they are a factory head of any kind other than 906 or 062 casting Vortec they aren't worth it, go with a budget aluminum for nearly the same price.
 

·
Registered
Joined
·
4 Posts
Unless you need these for a numbers matching restoration or a specific race class that requires these by rule they are a complete waste, especially at 600 dollars. That kind of money will put you into a much better head whether that’s an L31, Vortec or something from the aftermarket.

There is no way to recommend these head’s for a performance build, they are physically weak and thus crack prone and are waaay down on power. A 2.02 intake on these head’s is totally meaningless. The ports even after porting just can’t feed the curtain area a larger valve provides and tge casting is not thick enough to port them to a size needed to feed that valve. Those head’s that came from GM with big valves were just a feel good exercise for the nonsense (especially for the understanding of these things in 1970) that ipso-facto big valves are bettter, this isn’t necessarily true.

Kindly reread what I originally wrote I’m not blowing smoke, I don’t care how much Brzezinski says about the miracles that can be performed on these head’s, unless your aimed at a specific stock racing class or you are building a numbers matching historic car, these head’s are best avoided. In that regard he’s always looking for cores of this head but I doubt he’s paying 600 dollars per pair.

Actually with modern head’s you can pull equivalent power to the cam your leaning toward with a smaller cam. This gets into dynamic compression ratio which is a measure of stroke used to the point where the intake is seated. Especially if you are running pump gas this is important as to the octane limits of modern fuels. The later in the compression stroke the intake is closed the more the stroke is reduced thus the engines working pressure thus its power. Modern design for power on the available fuel tends to as little duration as gets the job done and more lift. More lift demands more instant port flow in exchange for more open time from duration. The plan here is to conserve operating cylinder pressure and regain filling with more valve opening. These days with modern head’s and a more moderate duration cam building a 400 horse 350 is something you have to work against rather than for. This just drops out of modern chamber head’s, a tight squish/quench of .035 to .040 inch, a cam similar to Comps XE276H, an Edelbrock Performer RPM intake and a carb in the range of 650 to 750 cfm with long tube headers and you’ve got 400 hp on a 9.5 compression ratio. Very potent, very streetable and uses 89 to 93 octane fuel. From a 1960’s early 70’s perspective this is or was unheard of from the 11 to 1 compression of the day.

So yes you can get to big numbers with these 487 head’s but your going to have to put a lot of cam and compression in the motor and without a piston change you can’t get even to the point where the compression challenges 91-93 octane. It’s just a hard row to hoe with this historical stuff to get modern power. So it boils down to what you are doing in that is this a numbers matching museum piece, a class restricted racer, or a hot street build. If the latter I’d scrap the 487’s and go with a modern head whether aluminum or iron because that’s where the power is even with your old style cam choice there just is this large increase in torque and power just sitting there to be plucked with Ricardo chambered head’s within today’s fuel capped compression ratios.

My preference runs to aluminum head’s as they allow crazy high compression 10-11 to 1 because they move heat so fast. But even modern chambered iron do a great job on 9.5 to 1

Bogie
Thanks for your prompt response, that's what I thought about the heads, I have a lead on another pair of heads.
 

·
Registered
Joined
·
4,259 Posts
I have had good luck asking around if people are doing a LS swap.

I have bought a running 383 with world heads, 1.7 rockers and some other junk for $1000

I also bought a carbutated 355 with vortec heads for $800.

Both of these engines ran great and had less then 50k on them. I beat the snot out of them floating valves and such offroad eventually running them out of oil in off camber situations.

But I basically had the cost of the heads alone into them. So it pays to ask around before you tear down a block and throw 3 or 4 grand and 3 or 4 months into building a 350 or 400hp engine. When you could have same hp broke in and ready for $1000 next weekend.

You need to check a few things when going this route. But if someone wants a LS then they are usually ok taking a loss on a built sbc that they no longer have a use for.
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top