Need Some Chevy Head Advice

[Bib_Overalls]

Friend of mine just scored a 283 short block assembly. It has been sitting for a while.  But it is supposed to be a low mileage rebuilt unit.

In any case, he needs heads.  I have a set of Power Packs.  But they will need new seats and are most likely to far gone to be economically rebuildable.

I also have a set of run-of-the-mill 305 heads.  The 305 bore is slightly smaller than the 283 so the combustion chamber should be fully over the piston and offer a tad bit of additional quench.  And they are unleaded gas friendly.  Is this a practical swap  :?:  

Garry lives in San Antonio and I live up here in the boondocks.  We are going to hook up at the pre-war swap meet in Oklahoma later this month.  If one set or the other will work I'll take them along.  But there is no point in hauling a hundred pounds of cast iron across half the county if it won't work.

[enjenjo]

The 305 heads will work, and actually flow better than the power pack heads.  With some work, they can be made much better than the power pack heads.

[Bib_Overalls]

Thanks!  Never hurts to ask.  An especially so when you know a real expert is going to answer.  

[enjenjo]

Thanks!  Never hurts to ask.  An especially so when you know a real expert is going to answer.  

So when is the expert going to show up?

[1FATGMC]

The 305 heads will work, and actually flow better than the power pack heads.  With some work, they can be made much better than the power pack heads.

I think some of the 305's have a really small combustion chamber size (like maybe 58cc's), and if yours do you might want to figure out the final compression ratio first.

THIS SITE has a Dynamic Compression Ratio program that you can download that includes a part that also figures the static compression.

If the 305's need to be rebuild I would look at some aftermarket heads myself.  Vortecs might have too small a combustion chamber also, but  World SR heads (I have these and like them) are a good deal for an iron head and the other iron head I would look at closely are the Dart Iron Eagle.  They have a new Iron Eagle series called the Iron Eagle Platinum which offer better flow and combustion chamber design over the older Iron Eagles.  I've seen them for $800-900 a pair.  Only problem is the smallest runner I see for them is a 200 cc intake runner (better for a 350 or 383).  You can still find the older Iron Eagles in a 180 cc runner (better for the 283 and street) for about $700-800.  You can get the world heads and dart heads in different cc combustion chambers 64 to 72-76cc.

One last thing I for sure would want to check that any after market heads are going to work with the small bore size on the 283.  

Personally unless he really wants a 283, why put the money into one when even a Mr Goodwrench $1300 350 will run circles around it and you can't tell them apart by looking at them.

c ya, Sum

Edit Note:  Doing a search I did find some Dart 180 CC Platinum Iron Eagle Assembled Heads on eBay, so maybe they do make a 180 cc head.  They have a buy it now of $729 and they are new.  They show a 64 cc chamber, but most all the Darts come in both the 64 cc and 72cc chamber.

eBay Heads

[kb426]

I'm a real fan of the 305 heads. I don't hear about them cracking alot. The castings on the early heads were notorious for lack of consistency on the ports. The Racing Head Service people told me back in the 80's that they would flow 400 pairs of heads to find one set of good ones to sell to racers.

[1FATGMC]

I'm a real fan of the 305 heads. I don't hear about them cracking alot. The castings on the early heads were notorious for lack of consistency on the ports. The Racing Head Service people told me back in the 80's that they would flow 400 pairs of heads to find one set of good ones to sell to racers.

Were they running them in stock car classes where the rules dictated stock heads and they could use these to jump the compression ratio way up there on a 350.

I used that calculator, from my other post, and it looks like with the 58cc heads on the 283 the static compression would be about 8.7 to 8.9.  Lower than I thought.  Knowing that I would probably go with what the wise man (enjenjo) suggested .  I guess I should have know that to begin with :cry: .

On a 350 with flattop pistons the 305 heads give around a 10.7 static compression ratio.

c ya, Sum

[Crosley.In.AZ]

On small bore engines the large valve heads can have problems with a large / high lift camshaft.

Possibly not a concern here.
.

[Dave]

Friend of mine just scored a 283 short block assembly. It has been sitting for a while.  But it is supposed to be a low mileage rebuilt unit.

In any case, he needs heads.  I have a set of Power Packs.  But they will need new seats and are most likely to far gone to be economically rebuildable.

I also have a set of run-of-the-mill 305 heads.  The 305 bore is slightly smaller than the 283 so the combustion chamber should be fully over the piston and offer a tad bit of additional quench.  And they are unleaded gas friendly.  Is this a practical swap  :?:  

Garry lives in San Antonio and I live up here in the boondocks.  We are going to hook up at the pre-war swap meet in Oklahoma later this month.  If one set or the other will work I'll take them along.  But there is no point in hauling a hundred pounds of cast iron across half the county if it won't work.

speaking of ..Anyone need a set of chevy 202 heads I just happen to have a set. Im sure they prolly need to be gone thru but ............
Dave

[EMSjunkie]

I just might be interested.

I have a set of 461 casting 1.94 / 1.50 heads, but one of them
developed an extra bolt hole, after a valve head broke off  

what casting number are they?

don't matter if they have accessory holes or not, ain't picky.


lemme know what ya want fer 'em.


Thanks Dave


Vance

[rumrumm]

You can get S/R heads at a reasonable price, but they have the old style D shaped chambers, and you have to run more advance than you do with the Vortecs which have the newer high swirl chamber. There is not a lot  of difference in price between the two, so a lot of people are using Vortecs. As  has been stated, 305 heads work great on 283's, and if you have some bowl blending done, they will flow exceptionally well on a 283 and still give you some badly needed low end torque.

[GPster]

I hope someone will clareify one item that may be completely off-the-wall. Somewhere in the midst of these engines manufacture the changed the angle of the intake manifold bolts. If I scored a 283 and found a good set of late model "Smog" heads the "scoring ' might not be so good if I had to buy an intake manifold. GPster

[1FATGMC]

I hope someone will clareify one item that may be completely off-the-wall. Somewhere in the midst of these engines manufacture the changed the angle of the intake manifold bolts. If I scored a 283 and found a good set of late model "Smog" heads the "scoring ' might not be so good if I had to buy an intake manifold. GPster

Joe from what I know, not much, the vortecs are going to have the different bolt pattern and need a special intake to match the intake runners.  I also think heads off of most anything from about 90 up like caprice heads and going to have the different bolt arrangement.

The other problem, Tony brought it up, is with the small bore on the 283 the valves on later heads could hit the cylinder wall sides at the top of the bores as they are larger valves.  If you look in the specs most of the aftermarket heads say 327's to 400's.

I still say why put money into a 283, more than it would take to build a 350 unless you have some special reason.  My Chevy wagon had a 283 and I liked it, but it was down on power.  Put an old 283 4 barrel intake manifold with the breather in front and use other 283 dress-up parts and lie about the 350 you built .

c ya, Sum

[GPster]

Put an old 283 4 barrel intake manifold with the breather in front and use other 283 dress-up parts and lie about the 350 you built .c ya, Sum

The 350 I have is out of a '79 truck and is 4 bolt main. It is more capable of excess speed than I am but I bought it for the Jeepster thinking that if I never became able to drive (anything let alone the Jeepster) "overkill" would be easier to unload. Swanton has been my furthest trips since I started driving and a 2300 four cylinder has done the job. My comment was not so much for myself but to prevent the reoccurance of someone having to ream out the holes in a manifold and build wedge shaped washers to make something that "just bolts together" work. GPster