1979 Original Project Thread

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  #81  
Old 12-18-2011, 06:18 PM
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So how does it fit to the valance and fenders? Mot the glass hoods don't seem to have good alignment and take lots of contouring to get them close. Looks like the passenger side front corner is a bit high?
 
  #82  
Old 12-18-2011, 08:54 PM
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Originally Posted by Axle
Just an update. I decoded the cylinder heads, they are 462624 heads! Factory 1.94 intake 1.5 exhaust. Best 350 bucks I've ever spent!
I don't get the victory celebration here. Those are run of the mill smog heads. 1.94" are not very desirable unless there in a Vortec head.
The 624 is a light weight version of the 882 head.,. one of the worst that GM produced and not intended for high performance use.
There are better heads out there.

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Key Cast Marks Cast Nos. Description

A Rectangle 460 ‘55 & up 265/283 low comp (8:1) 1.72/1.50 valves

B Narrow triangle over rectangle 520, 896 ‘58 & up 283 PowerPak/’57-’60 Fuel Inj.,9.25:1 CR, 1.72/1.50 valves, 59cc chamber; could be good replacement on late 305 but no accessory bosses.

C Vertical bar over rectangle 997 ‘57 Corvette 270HP, 9.5:1 CR, chamber similar to PowerPak but with sharp corners in plug shroud area

D 2 vert bars over rect 997 ‘56 Corvette 2X4 bbl, 283; ‘58 pass car FI; chamber same as ‘57 270HP Corvette

E, F Large “camel humps” 291, 461, 461X, 462 Original hi-perf or “fuelie” heads; chamber sizes are 62-64cc; both 1.94/1.50 & 2.02/1.60 valve versions available; 291 on 327’s thr ‘68; 291 have temp sender hole; 462 don't

G Left-facing right triangle 041 ‘69-’70 350/300HP, accessory bolt holes, most have 1.94/1.50 valves

H Small “camel humps” 186, 492 Later hi-perf or “fuelie” heads, some 186 (‘69 & later) & all 492 have accessory bolt holes; 1.94/1.50 or 2.02/1.60 valves; 64cc chambers; ‘70 LT1/Z28 use 492; avail as PN3987376

I Large triangle over rectangle (“crown”) 882 Large chamber (76cc), hardened exhaust valve seats, compromised intake port(‘71-’76 350/400cid), best of lightweight heads

J NONE 113 ‘86-’90 Corvette/ present 350-HO aluminum, no exhaust heat, 58cc chamber, 1.94/1.50 valves, centerbolt valve covers; good street head, ‘88-on have raised D ex port, 3/8 screw-in studs

K 3 right-facing “stairs” (“bench” on intake runner) 487 ‘71-’76 76cc, best large-chamber head; 1.94/1.50 & 2.02/1.60 valves available; latter machined for screw-in studs & guideplates

L Right-facing “bench” 993 Common big-chamber head, not a lightweight casting; sim to 487; may have steam holes

M One triangle 882 Alternative marking for 882; see I, above

N 2 triangles 624 Late-model lightweight casting version of 882

O “Saddle” and vertical bar 416 Late-model 305, conventional valve covers, intake port not restricted; lightweight; 57cc chamb

P Double (Captain’s) bars 193 Mid-’80’s style centerbolt cover with restrictive vane cast in intake port (hi-swirl); not recommended for high-performance applications.

Top Ten Production Chevy SB Cylinder Heads

No’s 1-6 are small-chamber, hi-comp and must have dished pistons to get comp below 10.5:1. No’s 1-7 have nonhardened exhaust valve seats which must be replaced for use with unleaded fuel.

No’s 1-6 are small-chamber, hi-comp and must have dished pistons to get comp below 10.5:1. No’s 1-7 have nonhardened exhaust valve seats which must be replaced for use with unleaded fuel.

Rank Cast # Good Points Bad Points

1 3782461X Hi comp (57.5cc), best ports of any OEM production cast-iron head, intake runner vol 170-180cc No accessory bolt holes, rare, likely to be cracked, 2.02/1.60 versions very rare

2 3991492 ‘70 hi-comp (61.2cc), good ports, acc bolt holes, 2.02/1.60 valve versions have screw-in studs & gplates Close proximity of water jacket to spring pocket on 492s cast prior to 1972 req special seat cutter if using larger springs

3 3890462 Ports similar to 461, but better comb chamber shape More common than 461-461X, but still rare; no acc bolt holes

4 3782461 Similar to 461X but with smaller intake ports Rare, probably cracked, no acc bolt holes

5 3927186 ‘64-’70, av chamb vol 64cc, ‘69-’70 have acc bolt holes Rare, valvespring seats close to water jackets

6 3947041 ‘69 350/300 HP, good chamb (similar to 462), acc bolt holes Very rare, valvespring seats close to water jacket

7 3932441 ‘69-’70, large chambers (73cc), some have steam holes for 400 blocks, ports decent, accessory bolt holes No 2.02/1.60 valve versions from factory

8 3973487 ‘71, 76cc, like 441 but better chamb, hard seats, acc bolt holes Big chamb needs domed pistons to get hi-comp

9 3998993 ‘71-’76 US/ ‘85-’88 Mexico, similar to 487, widely available Big chamb needs domed pistons to get hi-comp

10 332882 ‘71-’76, 350/400, big chamb, acc bolt holes, hard seats Changed intake ports, become worse, BEST of the worst

11 462624 ‘76-’78, 305, 58cc chamb, 1.84/1.50 valves, hardened seats, accessory bolt holes, best of the 305 heads 1.84/1.50 valves and ports too small for large cid; accepts 1.94/1.60 valves & seats

Casting no’s. & Date codes are cast on top of head (under valve cover) between second & third rocker arms from left.
First letter (A through M) is month (Jan through Dec)(I not used), one or two digits for day of month, one digit for last digit of year cast.
Lightweight castings (not for hi-perf use) have “scalloped” edge below exhaust ports; regular have straight edge.
 
  #83  
Old 12-18-2011, 09:21 PM
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Where you confusing them with a 461 or 461x? I could see then. I'm not picking on you BTW I was just wondering why it was the best $350 you spent. It is a good price for a running 4 bolt 350, don't get me wrong. Not rying to put you down, I'm actually trying to save you from a headache.

I did a quick search and all I come up with are these quotes.

624 casting are probably the worst of the gm light weight castings for cracking. These are THIN they crack across the exhaust seats and thru to the heat crossover. They will not tolerate much decking either.

I would find some better heads to start with. Even 882's are better.
That particular casting number is a light weight casting that is known to crack.
No matter how you slice it, 624 heads are horrible. Until they are gone, there isn't much you can expect performance-wise.
 
  #84  
Old 12-19-2011, 06:07 PM
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The hood is just sitting loose in the picture, but non the less it still isnt a good fit, it does help with the sleeper look though! lol

Too much reading for now, but yes $350 Canadian is an amazing price for a running 4 bolt and also being able to pull it yourself and not have to haul it away. Keep in mind parts regardless of what they are, are half the cost in US then it is here in Canada. It's been awhile since I played with the heads so Im not doubting anything your saying, but my focus isnt there right now, its just to get the car running, working on it when it is still a fair ways from running isnt fun anymore, SO #1 is get it running, #2 assess it #3 now we can tinker and make it faster and faster
 
  #85  
Old 12-19-2011, 09:31 PM
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maybe once u get it running it will help u get more motivated,always nice to have ur toy running,better than mine dont even have an engine yet,well i have the motor its sitting in my 87 irocz until im ready for it.so yes i do have a running hotrod just not my favorite one the 80 camaro,plus its tearing my iroc to pieces already shattered my t-tops once.LOL
 
  #86  
Old 12-20-2011, 12:06 AM
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I agreed it was a good deal for the engine. I thought you were getting pumped up over the heads.
 
  #87  
Old 12-24-2011, 10:19 AM
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but did u see the flow rate on them heads its pretty good.happy christmas eve everyone.
 
  #88  
Old 03-18-2012, 09:33 PM
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WELL ITS RUNNING, AND I DROVE IT! and thats about it! Pictures soon. It is rather loud! I have a foot of pipe directed down coming off the headers. Remember, I did everything so that I could drive it and get some motivation back, and it's back! I will be in touch with pictures and hopefully some video. See ya!
 
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