Fastcamaro87

ok i have the oppurtunity to get a set of the very rare and hard to find 462 casting
double hump heads, i am currently building a 406 small block and i am wondering if these
would be a good set of heads to go with, i plan on using a heavily ported/siamesed tpi
setup with a 52mm throttle body, and i will port the heads and fit them for oversize
valves, i can pick these up for $150 and it sounds like a good deal, any responses will be
greatly appreciated thanks very much

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87 IROC-z 305 TPI 5spd 10-bolt 3.73 posi ,8.8 Accel wires , bosch platinum +4 plugs,MAF sensor screens removed, gutted air box, ram air, K&N air filters,TB coolant bypass ,polyurethane tranny and torque arm mounts, K&N oil filter,Mobil 1 synthetic oil 20w50, futura GLS super sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

RB83L69

They don't have bolt holes in the ends.... it might be a bit difficult to install your accessories without them. That's why those are $150 instead of $450 or whatever like the other good heads that will work in late-model cars.

I would recommend that you pass and keep looking.

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"So many Mustangs, so little time..."
ICON Motorsports

Jim85IROC

iTrader: (2)

I've got 461s on my IROC, and as a result, I have no A/C.

The heads are decent, better than L98 heads, but nothing compared to vortec heads or the slathering of aftermarket choices.

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Fastcamaro87

well one of the heads is a 186 casting, and has the accessory bolt holes, the other is a 462 acording to everything i have found, they are identical except for the accessory bolt holes, also can i have the 462 casting drilled for the accessory bolt holes?and on top of everything else i am a college student working on a very tight budget, so cash is limited, thanks

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87 IROC-z 305 TPI 5spd 10-bolt 3.73 posi ,8.8 Accel wires , bosch platinum +4 plugs,MAF sensor screens removed, gutted air box, ram air, K&N air filters,TB coolant bypass ,polyurethane tranny and torque arm mounts, K&N oil filter,Mobil 1 synthetic oil 20w50, futura GLS super sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

AlkyIROC

The heads are 30 years old with 30 year old technology. 30 years ago they were performance heads because there wasn't anything else to use.

$150 may be cheap but by the time you port and polish them, install bigger valves, have screw in studs installed, have the spring pockets enlarged for bigger springs it'll cost you more than what it would cost to just buy some Dart heads that will already have all that work done, have better castings and flow better right out of the box even after you port the old ones.

And that's not guarenteeing the 30 year olds aren't cracked.

Leave those old heads for someone who is building a numbers matching car or someone who needs them because they race in a class that says they must run a factory head. By today's standard they are not performance heads any more.

Those heads were originally designed for 350 engines. Ported they could feed a 383. They won't flow enough air to properly feed a 406.

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87 IROC-Z SuperPro ET Bracket Race Car
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87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

[This message has been edited by Stephen 87 IROC (edited August 16, 2001).]

RB83L69

They're not identical... look closer. The 186 has the "squish" area under the spark plug, the 462 does not. So you'll have one head that will run OK on nodern gas (the 186) and one that will tend to ping.

Like everyone else is saying, they were good for their time (the 462 went out of production 35 years ago, the 186 31) but we've learned alot since then.

You cannot drill the bolt holes in non-bolt-hole heads. The boss on the outside of the head where the hole should go isn't there, and the boss of material in the water jacket (which you'd hit in about ¼" of drilling) isn't there either.

I have 2 sets of 186 castings, one on my 400 and one on the 305 that is currently in the car, plus a set of 492s laying around somewhere, so I have pretty good familiarity with those heads. Stephen about summed it up; if the heads are already worked up then they might be OK as a budget slap-together until you can do something better; but to work up a set of those castings in OE condition into a competitive motor will cost so much that for less money you can get a pair of new, aluminum aftermarket heads that will outperform them.

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"So many Mustangs, so little time..."
ICON Motorsports

Fastcamaro87

thanks for all the reply`s guyss i think ill hold off until i find something better.and on that note, will a set of aluminum l98 heads work any better?

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87 IROC-z 305 TPI 5spd 10-bolt 3.73 posi ,8.8 Accel wires , bosch platinum +4 plugs,MAF sensor screens removed, gutted air box, ram air, K&N air filters,TB coolant bypass ,polyurethane tranny and torque arm mounts, K&N oil filter,Mobil 1 synthetic oil 20w50, futura GLS super sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

Basett_Racing

Not trying to start a fight, but the 462 head does have the squish area, resulting in a 64 cc chamber as does the 186. I know because I have at least one set of each and I have actually cc'd them. Now the 461 head has no squish area, and it is a 62 cc chamber. The 461 was the first double hump design, it debuted in 1964. The 462 design came along later, the earliest casting date I've ever seen is 1966, but they may have came out in '65. The accessory bolt heads started coming out in '68 and was used through '70.
But in response to the original question, if you are on a budget, and simply can't afford anything else, they're better than any other factory head besides a Vortec (excluding LT1, LT4, LS1 of course) I recently built a double-hump headed 355 in a friend's 76 Nova, and it went 7.11 @ 99.80 in 1/8 (that would be 11.20-11.30 at a quarter mile track) two weeks ago w/ a 100 HP shot of NOS. It went 7.60's @ 89-90 on motor. So there's no doubt that they can go fast. I ported them, and sent them off for a valve job for him. He bought them for $200 w/ screw in studs, guide plates, Manley Valves, and good retainers/locks (They had aftermarket springs, but we replaced them anyway. He ended up only having around $400 in them, so he did good, but if he would bought all the aftermarket hardware + machine work, he would have went with some aftermarket ones for sure. It's easy to spend $800-$900 on hopping up factory heads, but when you can buy World Products Sportsman II's for around $700 or Dart Iron Eagle's for around $850, it's not worth spending that much on inferior heads. Like I said, I have 4 sets of stock double humps put up in my shop, but look at my sig, and you'll see that I opted for the Darts.


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82 Z28 383, Ported 215cc Dart Iron Eagle Heads 72 cc Comb. Chambers, Comp custom grind Hyd roller cam, Speed Pro .250" domes, Wheeler Motorsports 4340 I beam rods, Eagle 5140 steel crank, Weiand Team G intake, Holley 830 DP, hedman headers
Trans: Turbo 350 w/ 4000 stall -- Rearend 7.5 w/ Richmond 4.10's, Auburn Minispool
Best ET:11.60 @ 114.56, w/ a 7.34 1/8 @ 93.50, and a 1.622 60'


89 RS, L03 305, Hypertech Chip,cat delete, Dynomax exhaust,K&N open element Filter,160 stat, MSD coil --Trans:700R4 Corvette Servo -- Rearend: 7.5 GM 3.42 w/ posi-lock

Bassett Racing

94-6spd

I have a set of those double humps also. I did some figuring and found that vortecs were alot better as for performance and cost. I bought a set of vortecs off ebay for a good price and ported them myself. I also had a 5 angle valve job and the valves back cut. I don't have alot in them and they really do perform well. Check ebay.