what heads are these?

[justin4260]

ok I've got a 400 small block with 2 different heads. I'm trying to find a place to get another one of this casting number 330545 and casting date d2 73. a guy i know told me he looked it up in a book and said it was a corvette head. i went t the auto parts store and they said they make reproduction heads but they don't search by the casting number they go by the vehivle and then they can chose valve sizes and what not. so i looked he head up and got 2 different sources saying different things. one place said it was from a 307/350 and another from a 350/400. well i know you can't put 350 heads on a 400 so I'm wondering why they worked even though its a 400 block unless they were 400 heads. any info would be great.
the first picture is the casting number
second picture is what outintheshop.com said
third is what nastyz28.com said

[Norgermish]

Originally Posted by justin4260

well i know you can't put 350 heads on a 400 so I'm wondering why they worked even though its a 400 block unless they were 400 heads. any info would be great.
the first picture is the casting number
second picture is what outintheshop.com said
third is what nastyz28.com said

Just a quick thought, you can put 350 heads on a 400 block. All that is needed is to drill the steam holes between the combustion chambers. There are six holes 2 between each chamber. I've done it on common castings, 882's, 993's, even 624's before

[Norgermish]

It's probably going to be relatively tough to find 1 single 330545 head. Looks like your has guide plates in the photo, so it would be the 2.02/1.60 valves. Just curious, you said it has 2 different heads, what is the casting# on the other head?

[geezer#99]

Let's sum it up!!
You have two mismatched heads on a sbc!
Is it a 400? Or 350? Or who knows what?
What's the casting number?

[bruceman1968]

Justin has a 400 small block http://67-72chevytrucks.com/vboard/s...d.php?t=668726 When he replies I think we will find that the casting number on the other head is 3998993. If you read the note in the clip I posted you will see that the 330545 and 3998993 heads are the same except the 3998993 head is machined for 1.94/1.50 valves and push in studs. Any good machine shop can machine the 3998993 heads for 2.02/1.60 valves and screw in studs. Both heads are thick castings and NOT prone to cracking. After the machine work has been done(including CCing the heads and reworking where necessary) the heads are virtually identical, except of course for the casting numbers and casting symbols. Lets see what Justin says the casting number is on the other head. I'm betting on 3998993 with the machine work completed.

[justin4260]

the other head casting number is 333882 atlas thats what i think it is. the block is a 72 400 small block from a 72 impala. wow bruceman1968 your pretty good. also could somebody clear this up for me, can you use 350 heads on a 400 or not? some guys told me you can't and some say just drill the steam holes. what happens if you don't drill the steam holes?

[enaberif]

Lots of people rip on the 882s because they are only aware of the light casting. If you have a 882 heavy casting they are nothing special and just a standard sbc head. But the heavy castings are not going to crack as easily as the light.

[bruceman1968]

Justin, here's some info on your other head. Still no reason to look for a new one.

[kwmech]

You can use the 350 heads on a 400, don't hesitate to have the holes drilled or you can do it yourself with using the 400 gasket as a template and an 1/8'' drill bit at a slight angle away from the combustion chamber

[justin4260]

so can the 882 head have the valve size changed to 2.02/1.6 like the 545 heads?

[bruceman1968]

Justin, you CAN run 350 heads on a 400 block. Just make sure to drill the steam holes. If you don't steam builds up making a hot spot and you start blowing head gaskets.

[kwmech]

2.02s aren't really necessary on a 400 unless you're going to put it on the track all the time.

[justin4260]

Originally Posted by bruceman1968

Justin, you CAN run 350 heads on a 400 block. Just make sure to drill the steam holes. If you don't steam builds up making a hot spot and you start blowing head gaskets.

maybe that why i blew a head gasket on the 882 side (passenger)

Originally Posted by kwmech

2.02s aren't really necessary on a 400 unless you're going to put it on the track all the time.

it will be a daily at first but once i get a second car its going to be my hot rod truck. but try and keep the original look to a point.

[justin4260]

does anybody have a picture of what the steam holes look like? id rather not have to pay to have somebody drill for me but i also don't want to drill them wrong.

[bruceman1968]

Originally Posted by justin4260

so can the 882 head have the valve size changed to 2.02/1.6 like the 545 heads?

Yes the 882s can be machined for 2.02/1.60s. But some of them came with 2.02/1.60s from the factory. Your 882 head has screw in studs with guide plates, so they probably came with 2.02/1.60s and are the heavy casting. I think it's time for you to spool that motor up and let it eat!

[bruceman1968]

Justin, you can use the head gasket for the 400 as a template to mark the steam holes. Some will tell you that all six holes need to be drilled and some will say that only the lower three need to be drilled. Either way you can do this yourself but it won't cost much to have a shop do it either.

[justin4260]

Originally Posted by bruceman1968

Yes the 882s can be machined for 2.02/1.60s. But some of them came with 2.02/1.60s from the factory. Your 882 head has screw in studs with guide plates, so they probably came with 2.02/1.60s and are the heavy casting. I think it's time for you to spool that motor up and let it eat!

is there a way i could measure to make sure the 882s are the 2.02/1.60 and the thick casting not thin? and also I'm not familiar with heads to much. what are screw in studs and guid plates and the significance of them.

[bruceman1968]

Check the exhaust valve spring seat dimension. .84 indicates 2.02/1.60s

EDIT: sorry I missed part two. push in studs can work their way out. Screw in studs stay put. Guide plates help with push rod deflection. Screw in studs and guide plates are used on high output motors.

[justin4260]

[QUOTE=bruceman1968;7169191]Check the exhaust valve spring seat dimension. .84 indicates 2.02/1.60s

do i measure the diameter of the spring itself? and is it inches?

[bruceman1968]

.84 is the inside dimension. Your going to need the head apart(springs out) to measure it. It is in inches. Thousands of a inch. Are the heads off this motor? Do you have a micrometer/dial caliper? If the heads are off then just measure the diameter of the valve. The .84 is the inside dimension of the valve seat. I should of just told you to measure the big diameter of the valve itself. But you need the head off to do so.

[justin4260]

the heads are not off yet but the will be off soon. i believe my dad has a digital caliper i can use if not i can rent one at the local parts store. if i take the valve out is there a specific way i need to put it back in?

edit: what are some other things i should check while i have the heads off. in the heads and the cylnders.

[bruceman1968]

You won't need to take the valve out to determine if it's a 2.02 or a 1.94. You know that the valve on the 545 head is 2.020, so you should be able to compare the two heads visually to see if they look to be the same size. The difference between a 2.02 and a 1.94 is .080 thousands. That's about 5/64 of a inch. You should be able to see that visually, with both heads out side by side. If not you can use the dial caliper to help you determine it. It will be tricky to measure the valve with it still in the head. So if you can't see the difference then measure between the two valves with your dial caliper. It will be much easier to measure the space between, than the actual valve itself.

[justin4260]

when i change the head gaskets, do i have to get the heads and block machined? is there something I can do myself so i don't have to take it to a shop?

[mMad Dawg]

According to the Chevrolet Small Block Interchange Book your882 heads are the light casting and prone to cracking. They say 487 493 997 and 330545 from 17-74 will interchange.All but the 487 heads come with 194/160 valves. They are rated as intermediate performance. You can use 350 heads on a 400 but they have to have the steam holes drilled out or else they will overheat. A 400 head can also be used on a 350 but you must use a composition gasket. Hope this helps.

[mMad Dawg]

Sorry that should read 71-75.