I looking for a set of better factory heads for my stock 283. In my search, I have been told that there are both open chamber and closed chamber small block heads. I know this is true for big block heads, but my casting numbers reference book doesn't mention this at all for small blocks. By the way, the casting number on the heads that are supposed to be closed chamber is 462.
Thanks in advance. DRuss32

how about a set of S/R heads from world?

I haven't been looking at aftermarket heads. Just original Chevy stuff. I want the motor to have a very traditional look so it goes with the traditional theme of the car. The era is late 50's to early 60's.

Cost and condition are also considerations. Do you know of a good source for used World Products heads?

Druss32

Are you looking for stock replacement heads? or a higher performance factory head? either way, look here:
http://www.mortec.com/castnum.htm

This site will tell you what you need to know, just read the notes beside the casting numbers, the camel hump heads and others are usually all over Ebay, but you gotta be careful, if the guides are shot you`ll spend more money replacing everything in them than you would have just buying a new set of aftermarket heads.

Can you answer the question I asked in my original post?


Do factory small block Chevy heads come in both open and closed chamber versions?

Thanks.

The answer is yes, however, it`s not how small block heads are referred to, it`s usually just said small or large chamber. Anything under 68cc`s on a factory head is referred to as small chambers or closed chambers. The CC listing per casting on the mortec site will tell you which are open and closed.

You need the closed chamber heads (small combustion chambers, 64cc) for a 283. Open chamber heads are 76 cc and will drop the compression ratio of a 283 off the map.

World S/R Torquer


These heads have 170cc ports, 58cc chambers and 1.94/1.50 valves to work with the 283's small bore size. They have hardened seats for unleaded gas, better combustion chamber shape, and have the old style bolt patterns unlike Vortech heads.

They're just plain better than the old heads.

Larry

When I rebuilt an old 283 on my 57 Chevy truck, the heads didn't have accessory holes which really sucked trying to install an alt or PS. I'd go with aftermarket iron heads and paint to match. You'd gain better performance. Not many would know its not a "true" GM head.

i was told that open chamber would slow a stock 283 down on hp

I got a set of 305 heads from a mid 80's something with the 55cc chambers off ebay for my 283. They were rebuilt, nothing special, but nice and clean and ready to go.
I have only run the motor to break in the cam, but they seem to work just fine.

yeah

he's sayin the 76cc heads would drop the compression too low for that motor... which i'd believe, since it's gonna be tough to keep it up with the same volume on the 350 I'm putting together. Been playing with measurements all night for compression on a 350 .030 over with those chambers... And I came out with 8.6:1 if I use a steel shim gasket and have the block zero decked.

Blob is on the right track here; get some 416 casting # 305 heads--small chambers will help keep the compression ratio up, and these are reputed to be the best flowing 305 heads (not necessarily saying a lot) available. With a little port clean up work they are known to power well set up third gen Camaros into the low 14s in the 1/4 mile.

http://www.beckracing.com/page21.htm#SECT1

The 4th piston from the top is a flat-top 283 piston. The chart will tell you what the compression ratio would be for different-sized combustion chambers.
Note there are no 76cc heads listed. CR would probably in the low 7's.

Note the compression height is 1.805". Some cheaper "rebuilder" pistons are shorter, just like the situation with 350 pistons.

Its True The S/R Torquer 305 Heads Are Nice On A 283. Any 305 Head Would Work Well Although It Would Depend On Whether You Wanted Max Performance Or Max Fuel Economy. CC's Were 58 Or 64 (Give Or Take) Intake Vaves Were 1.72" Or 1.84". Exhaust Valves Were All 1.50". Ferrea Makes Undercut Stem Versions For Them All Which Improves Flow. The 416 And 601 Are Two Contenders. 64CC Former, 58CC Latter. Both Are 1.84/1.50. Would Not Use Anything Bigger Than 64CC On 283. Maximum Torque And Fuel Economy Use 1.72 Intake Heads. Still Run Strong. (Original 283's Were 1.72/1.50.) Be Careful Of Someone Trying To Sell You 267 Heads For 305 Heads. Although The 267 Was A Fine Motor As Were Its Heads, The Heads Were Unique To The 267 In That They Had The Smallest SBC Chambers Ever(Around 55CC's) Plus A Unique Exhaust Valve At 1.38". Intakes, Once Again Were 1.72". Insignias On The 267 Heads Were Unique- Kinda Like ^^ Except Narrower At The Bottom Of The ^. I Would Still Rather Have The 305's Or S/R's On A 283. (Put A Set Of 601's On A 262 In A 4-Speed Monza. 'Twas A Runnin' Lil' SOB, Aye And For Sure No One F'ed With It On Top End!) If You Use The 601's Gently Unshroud The Valves (Mostly Intake) And Eliminate The Sharp Edged Radius Where The Exhaust Just Leaves The Chamber At The Bottom Of The Port Near The Seat. Its Nice To Haul A## On Pump Gas! MW