Gasser HotRod Forums banner
1 - 19 of 19 Posts

·
Administrator
Joined
·
13,700 Posts
Spammer. He's history.

Never compared BBC to SBC head bolts as I always thought the length would be the big issue? I would have suspected that at the least you'd find yourself short on bolts for certain lengths, and excess for other lengths? The lower edge row of 8 bolts on a SBC head is more of those short bolts than a BBC has on it's lower edge. Not sure how the other points compare?

BBC-7/16-14
(8) 2.19 in, (4) 3.95 in, (12) 4.19, (8) 5.25 in

SBC-7/16-14
17 bolts to the set: 8 at 1.676" length, 7 at 3.823" length, 2 at 3.10" length.

So the 4 at 3.95" would likely work for a SBC, but nothing else would work.
 

·
Registered
Joined
·
7,603 Posts
I’ve had arp head studs interfere with roller rockers and the application was correct. So be careful and double check mismatched studs. Too long may be an issue.
 

·
Administrator
Joined
·
13,700 Posts
They look right.. I put one side on and slipped head on.. 487 casting 202 head with screw in rocker studs and push rod guides.. 71 Corvette I believe from casting #.
I have 487x heads on my '39 Chev SBC roller motor. I was told these 487 heads were used on both Corvettes and Z28 Camaro engines around 1971. The data says they are one of the highest flowing heads Chevy ever made, and compare well with a lot of aftermarket aluminum head flow rates.
 

·
Registered
Joined
·
125 Posts
Discussion Starter · #8 ·
I have 487x heads on my '39 Chev SBC roller motor. I was told these 487 heads were used on both Corvettes and Z28 Camaro engines around 1971. The data says they are one of the highest flowing heads Chevy ever made, and compare well with a lot of aftermarket aluminum head flow rates.
Yes they are either Camaro Z28 or Corvette.. screw in rocker studs and push rod guides from the factory.. I've heard they flow pretty good for cast iron heads. Thanks for everyone's input. I'll keep an eye on the clearances.. I just have alot of them.. enough to make a set.. I need to buy a set of roller rockers to check for interference. Thanks again.. I watched all of MMhotrod41 YouTube videos.. really cool stuff. 👍
 

·
Administrator
Joined
·
13,700 Posts
Yes they are either Camaro Z28 or Corvette.. screw in rocker studs and push rod guides from the factory.. I've heard they flow pretty good for cast iron heads. Thanks for everyone's input. I'll keep an eye on the clearances.. I just have alot of them.. enough to make a set.. I need to buy a set of roller rockers to check for interference. Thanks again.. I watched all of MMhotrod41 YouTube videos.. really cool stuff. 👍
Are you sure those screw in studs and guide plates were factory? Mine had neither when I bought them used. I had to have them tapped, and added when they rebuilt my 487 heads.
 

·
Registered
Joined
·
2,310 Posts
I'm fairly sure (notice I say "fairly sure", not completely sure) the only heads that Chevy offered with screw-in studs and guide plates were the cast iron angle plug "turbo heads" that took the smaller size "peanut" plugs. I think Chevy referred to them as their high performance off road heads.
I remember Blairs Speed Shop had a brand new pair sitting out on their display rack. Everytime I'd go in there I'd stand and look at them and just wish.................. It never came true :mad:

Gas Automotive wheel system Audio equipment Differential Machine
 

·
Registered
Joined
·
7,603 Posts
I found this info a while back.
Chevy Small Block Cylinder Head Identification Guide

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 CSB Cylinder Heads
Also Borrowed from CAR CRAFT Magazine
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
 

·
Administrator
Joined
·
13,700 Posts
Thanks Mario! I've often searched the internet for data on which SBC heads had screw in studs, but not much good info out there. Many people say that all the hi performance heads had them, but I know that's not accurate. They're really so inexpensive to buy, and most can D&T their heads if they have the tap, and a drill motor to drill the holes out. Toughest part is pulling all the old studs, but that just takes time, not special tools.
 

·
Registered
Joined
·
2,310 Posts
Here you go Vall.
. At about 1:19 he starts talking about the "292" casting factory high performance angle plug "turbo head". He never turns them over but does say that these heads were "the" head for almost any type racing; drag, nascar, off road, etc. I can't imagine a head being built for high performance motors without studs and plates. I'm almost positive that the pair at Blairs had them.
 

·
Administrator
Joined
·
13,700 Posts
I never heard him mention if they were tapped for screw in studs, unless I missed that? As far as performance heads go for Chevrolet cams, I'm also not sure Chevrolet ever offered a true high lift cam that would require screw in studs to keep it from pulling studs? It's pretty generally accepted that most machine shops will replace the pressed studs if the cam is .500" or higher, or if the engine is a very high performance engine. But I don't think even the old 370 hp 327's cam was over .500" lift? But I'd guess those heads had screw in studs and guide plates.
 

·
Registered
Joined
·
125 Posts
Discussion Starter · #15 ·
Are you sure those screw in studs and guide plates were factory? Mine had neither when I bought them used. I had to have them tapped, and added when they rebuilt my 487 heads.
Sorry just saw this.

As far as I know they are factory.. let me see if I can find the info I read about the 487 Corvette heads having screw in rocker studs and push rod guides and I remember it being the 202 valves only not the 194's. Although what I read may be not correct.
 

·
Registered
Joined
·
125 Posts
Discussion Starter · #16 · (Edited)
In regards to Corvette & Z28:
Base engine used 1.94/1.50 valves, pressed rocker studs and softer (less tension) valve springs with exhaust valve rotator cups; LT-1 used 2.02/1.60 valves, screw-in rocker studs with guide plates, stiffer springs and a different retainer. I Also read the screw in rocker stud guide plate heads are rare. I need to see if I can find the guide plates because I think they were stamped GM.
 

·
Administrator
Joined
·
13,700 Posts
Mine are 487x heads. Not sure what the "x" designates after the 487 ass everything I've searched online doesn't mention any difference between 487 and 487x? But mine were 2.02"x1.60" and press in studs. I suppose someone may have had them rebuilt previously and upsized the valves, which is easy to do, and not even do anything except cut seats for the larger valves.
I didn't have guide plates installed as I'm not a fan of guide plates myself. I've seen them wear out even hardened pushrods, and lose a pushrod. So I told the machine shop to not bother with guide plates when they rebuilt mine.
 

·
Registered
Joined
·
125 Posts
Discussion Starter · #18 · (Edited)
I believe the X designates an 10cc larger intake runner.. I read only the factory 202 valve cylinder head was machined for screw in rocker studs and guide plates. They did not machine the 194 cylinder head for screw rocker studs & guide plates factory. But both were low compression 75-76 chamber.
The 461 Fuelie or camel hump head is virtually the same as a 487 or 487X just with a higher compression 64 chamber just without accessory holes. If I remember right mine may be 487 not 487X. They are both high performance heads.. and I think the 487X never came with screw in rocker studs / guides, only the 202 487 head did. Fuelie head is a better for a naturally aspirated engine.. the 487 and 487X is better for supercharged / turbo engines due to chamber size. And I think the 305 H.O head is a 58 chamber.
 

·
Administrator
Joined
·
13,700 Posts
I believe the X designates an 10cc larger intake runner.. I read only the factory 202 valve cylinder head was machined for screw in rocker studs and guide plates. They did not machine the 194 cylinder head for screw rocker studs & guide plates factory. But both were low compression 75-76 chamber.
The 461 Fuelie or camel hump head is virtually the same as a 487 or 487X just with a higher compression 64 chamber just without accessory holes. If I remember right mine may be 487 not 487X. They are both high performance heads.. and I think the 487X never came with screw in rocker studs / guides, only the 202 487 head did. Fuelie head is a better for a naturally aspirated engine.. the 487 and 487X is better for supercharged / turbo engines due to chamber size. And I think the 305 H.O head is a 58 chamber.
Original 461 camel hump heads have smaller runners than the 487 heads. The 487 have 180cc runners, while the 461 has 160cc runners. There's a company remaking 461 heads cast in aluminum, and with larger 180cc runners. Those were great heads in their time, but pretty constricted flow compared to almost any SBC head today.
I have 461 heads on my Austin's 355 SBC, but they've been ported a little, and chambers slightly relieved where the valves were unshrouded.
 
1 - 19 of 19 Posts
Top