Angle plug / bowtie heads.
Thread Starter
Racer
Joined: Feb 2007
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Angle plug / bowtie heads.
Back in the day these things were like the holy grail for small blocks. Are there truely any performance advantages over standard 2.02 heads of the same CC? I have a set that have been sitting in my garage for 10 years and I was wondering if there were any true performance gains to be had from them and if so why dont we see all these after market heads that are everywhere now a days using the angle plugs? Just wondering, opinions? experiances?
Race Director
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From: Database Error Indiana
There was more to it than the angle plug. Bigger ports, thicker deck surface and a slightly different shape to the chamber. Also most aftermarket heads give you a choice of angle or straight. The Bowties came in different phases. You can still get phase 2 and 3 from Scoggin/Dickey. Still a pretty good part for the price, although most prefer alluminum. You can get alluminum Bowties too. 
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Do you know which ones you have? Are they the Phase I, II, III-VI versions? Are they the Bowtire Iron ones? Are they the old 292 Turbo heads?
Either way, as mentioned, the real power was in the ports. The angled plug deal was primarily to get plug tip away from huge dome high compression pistons and not shroud flamefront so bad. That's why they were angled upwards also. On a normal compression motor with flat tops, sumps or small domes..there's no real advantage to angled plugs.
Newer heads are moving the plugs closer to center of combustion chamber..and that does help somewhat.
If you have 'em, I'd use them!
JIM
Either way, as mentioned, the real power was in the ports. The angled plug deal was primarily to get plug tip away from huge dome high compression pistons and not shroud flamefront so bad. That's why they were angled upwards also. On a normal compression motor with flat tops, sumps or small domes..there's no real advantage to angled plugs.
Newer heads are moving the plugs closer to center of combustion chamber..and that does help somewhat.
If you have 'em, I'd use them!
JIM
Thread Starter
Racer
Joined: Feb 2007
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Im at work so I cant quote the casting number but the heads have the chevy bowtie raised & cast into the head & they are iron heads What are the difference in phase 1,2, etc?
Mouse; what casting number? When you say bare do you mean just the heads with no valves etc. ?
Mouse; what casting number? When you say bare do you mean just the heads with no valves etc. ?
Last edited by L Holmes; Mar 31, 2007 at 01:43 PM.
Team Owner
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From: Orange Park Florida
Drifting
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I ran a set bought new in '76 and ran them for over 100,000 miles. They worked great, although it was before my G-tech days so I can't tell you how much, if any, better they were than the original 2.02s.
These days with low octane gas, aluminum is the only way to go....
These days with low octane gas, aluminum is the only way to go....
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Le Mans Master
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18 yrs ago was 14011058 they have been in the bottom of one of my closets all that time in the boxes they still look as new as when I
bought them. they are bare no valves the spring seats on these heads
are cut for 1.43 valve springs from the factory that is one of many
upgrades chevy done to them over the first 292 angle plug turbo heads.
higher tin alloy in the iron and improvements in the ports thicker
metal in the deck and thicker metal in places in the ports for someone
wanting to port them for racing.
Pro
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From: USA
I bought a set maybe 20yrs ago, maybe 30, just because they were ridiculously dirt cheap new from GM (cast-iron bow-ties), I think they're Ph I because they have the thin casting line between the exhaust port. put them on my roller-cammed '78 L82 for a while, that was a lot of fun, and very streetable, then when I swapped that out for a BB, they sat for a while. then I dusted them off, wiped them down and put them onto my daily driver TPI IROC, just because they were laying around (i.e. "free"), already had the Manley severe duty valves, good springs, titanium retainers, etc. and they've been on there ever since, probably got somewhere between 50,000 to 100,000 miles on them pulling yeoman duty. you just have to make sure the headers accommodate angle plugs...
they are indeed certified stone-age tech, probably just 2 generations beyond flat-heads, but back then, not much affordable hi-perf was available, not like nowadays, aluminum heads are damn near falling out of the trees almost.
they are indeed certified stone-age tech, probably just 2 generations beyond flat-heads, but back then, not much affordable hi-perf was available, not like nowadays, aluminum heads are damn near falling out of the trees almost.
Le Mans Master
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From: Fremont CA
Phase 1 bow ties weren't known as being very reliable....they tended to crack! My buddy told me he struggled greatly to get the bow ties to the level that his 292 Turbos heads were at when they first arrived. I have a set of phase6 aluminum heads NOS in the box and a set of AFR 292s the 292s I'll never sell, the phase 6s I'd love to sell but can't get $600 for them.....maybe make an end table out of them
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Phase 1 bow ties weren't known as being very reliable....they tended to crack! My buddy told me he struggled greatly to get the bow ties to the level that his 292 Turbos heads were at when they first arrived. I have a set of phase6 aluminum heads NOS in the box and a set of AFR 292s the 292s I'll never sell, the phase 6s I'd love to sell but can't get $600 for them.....maybe make an end table out of them
JIM
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Back in the early 70's every chevy hot rodder had to have some kind of double Hump casting head. I spent a lot of money improving my 186 casting and later my 292 casting. I used both on my Vette.
IMO - They are only good for someone who needs a period correct motor. They are very poor for performance because of the bad chamber and ports. I would never use them again.
IMO - They are only good for someone who needs a period correct motor. They are very poor for performance because of the bad chamber and ports. I would never use them again.
Race Director
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Yeah,,,but what the heck...never know what new comes out of it......
JIM
JIM
Le Mans Master
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what the heck we can update an old thread. i had a set of turbo castings back in the mid 70's? they were the first 2 sets in the D.C area. one set went on my 70 LT-1 corvette street car which picked up almost 3 tenths in a quarter mile, can't say there may not have been valve issues or weak springs in the heads i took off, but i was happy. the other set went on a 377 with heavy porting , tubes etc in a nova which ran 10:80 or thereabouts. which was dang good back then. there are a lot of heads today im sure are better , but they certainly aren't the worst head ever made. i think im remembering accurately im only senile on tuesdays
