I just picked up a set of 041 heads in nice shape with a recent rebuild with big springs, screw-in studs and guide plates for cheap. I did get less radical of springs for my mild 252 cam, and new teflon seals...

However, I noticed that the exhaust seats are fairly wide. They never had a 3 angle valve job done to them, either. Before I spend any more money on them, I want to know how I can tell if these heads will work with unleaded fuel.

Since I'm on a bit of a budget, I was thinking of going the Vortec route if the costs get to be too much with these heads, however, I would need either self aligning rockers, or screw in studs and plates for my current crane 1.6 rockers, making the vortecs fairly expensive.

I also have a few sets of late-smog heads around too... one set from a 1970 Chevy Implala 2 bbl 350 and 2 late 70's station wagon 350's. Not sure the casting #'s, as the motors are still together yet.

Oh, I'm building a mild-mannered 350 with about 330HP and 400 ft/lb tq from 2000 to 5500rpm. I'm looking for some opinions as to what you guys would do, or have done.

 

THe 041s are a perfectly good head to use for a good warm street-motor buildup. Forget the smoggers; throw them away.

041s IIRC had induction-hardened valve seats. They generally work OK with modern gas. However, without seeing yours, it's impossible to tell what's been done to them. They might even have had new seats installed in them.

If you don't have valves, buy Manley Street-Flow ones. http://store.summitracing.com/partde...AN%2D10722%2D8 and http://store.summitracing.com/partde...AN%2D10765%2D8 are the ones you should need (1.94"/1.6") unless the intakes are cut for 2.02" valves in which case you'd need http://store.summitracing.com/partde...AN%2D10766%2D8

Port them, especially clean up the area right behind the valve where the factory's cut for the seat meets the port in the casting; and remove any large obstacles you see to flow. Don't worry about enlarging th eports or "gasket matching", those aren't necessary. Just get the shape smoothed out.

Then get a good valve job done on them, and have the right valves on hand to get them lapped to the seats, and you should be good to go.

 

I've also heard that a lot of the hoopla surrounding hardened vs non-hardened seats is BS. There was a durability study done by the US post office when the switch was made from leaded to unleaded gas throughout the country. They found that over hundreds of thousands of miles and on all sorts of different vehicles that it didn't seem to make much difference in durability.

That being said, those were all low performance vehicles. My guess is that with the higher combustion temps found in a performance motor it might make a difference. I've still never seen an definitive testing to prove that though.

 

041's are good heads. if ya got 'em use 'em.

Follow RB's advice and you'll be very pleased with the performance.

By the time any noticable service life difference between a hardened seat (unleaded fuel) and a non hardened seat
shows up you'll be an old man.
Don't worry about it.

 

041 heads are a good set - 041x are a little better set. I had a set of '041s with 2.02/1.6 valves - 1.48" spings - screw in studs with guide plates. They had a mild port job and polished combustion chambers/exhaust ports. Nice heads - mine CC'd @ 180cc on the intake and 62cc chambers. The set I had were from a '69 or '70 350/370hp vette. Nice heads - made 400+ HP/TQ on my old 350.

 

Ok, thanks for the advice guys.

Just to put it into perspective, it'll be a 350, .020 overbore
Comp Cams HE252
041 heads 1.94/1.5
comp springs good to .500 lift
crane 1.6 roller tip rockers
hyp. flat-top pistons with 4-valve reliefs
Moly Rings
Cloyes Double-roller timing set
HV oil pump
Cast crank, .010 undercut
Proform HEI ignition kit
Bosch copper plugs
Edelbrock 600CFM carb
Performer intake

Desktop Dyno figures a 9.6:1 ratio and 325HP@ 5500 and 400 ft./lb. of torque from 2000-5000 rpm. I know it's not gospel, but with a stock convertor and 3.42 ratio rear, it'll be a great daily driver.

 

word of advice - sometimes desktop dyno under estimates true HP/TQ - seen it happen.

As far as I know of, there is not '041 head flow file for DD2000. Use the '462 flow file ( should be sbc_gm_462 ) - this has the same flow if not a little less then the '041.

 

I have a Jeep with a 350 chevy, I used to cruise the highway at about 3000 rpm for hours on end. After about 60,000 miles of that the valves sunk about 1/8 inch into the seats. The heads were from 1970, I think 882 castings. I've never had this happen before, maybe it was the constant 3000 rpm???

I got a set of vortecs and modified them to work with the early intake. Got some stock self aligning rockers from a friend, got some valve covers in the junkyard. My 1/4 mile times went from 14.27 (before I sunk the valves) to 13.49. I uesd to run 12.37 with N2) with the old heads, I think I'll be in the 11's with the vortecs and N2O but I'm afraid to try

 

i would definately add up the costs of doing each type, cause im thinking by the time you add in the cost of a valve job, possibly new valves, and all that stuff that you might be better off just selling the heads and rockers, and buying some vortecs and new rockers, the vortecs might cost a little more by the time your done, but not too much more, and its dyno proven that they are the highest flowing stock head, and make more power.... i used to work at a gmc dealership and they sold their core motors (not many dealerships do that) i got a vortec 350 4 bolt main with 9.6 compression and only 34k miles... reg cust price was around $300 for the long block, i paid $130, the reason the motor was pulled was because of low compression in one cylinder, turned out to be a bent valve.... in the end i ended up selling both heads and motor, but made a nice $300 profit... my point is its possible to find vortecs for cheap... vans with the vortec motors are starting to show up in junk yards...

 

Watch out for used Vortec heads. The Vortec truck motors have several problems with the intake manifolds that can ruin the heads. The manifold seals often develop leaks from people not doing routine coolant changes. This can create a steam pocket and end up cracking a head.

Also, the injector fuel pressure regulator can go bad and do one of several nasty things. The most severe of which is filling the motor with fuel until it hydrolocks and bends a rod, breaks or twists the crank, and does some serious valve damage.

A major remanufacturing facility recently stated that one out of every two Vortec heads they recieved for a core was damaged beyond repair.

The problem isn't the heads themselves, it seems to be the top end. I'm not saying don't buy used ones, but you need to be very careful, especially since new ones aren't that expensive.

 

My dad has the tools and experience to do the valve job, as he used t run a speed shop in the late 60's and early 70's, so that cost is factored out.

The valves I have to farm out, but it's fairly cheap to have done ( I barter in the "case currency" for that one) I already have rockers and intake I want to use, or else I am going to have to go with a bigger cam, new self-aligning rockers, studs and intake manifold. Once those all add up I'm suddenly looking at the cost of low-end aluminum heads or high -end Sportsman II's.

The more I've studied about the 041 heads, and the pile of parts I've amassed, I think they will be a good choice. My only holdback is the wide exhaust seat/unleadded fuel issue, which the general concensus seems to be that I'm worrying too much. If anyone else has experiences, I'd like to hear them!