186 Head ??? - Team Camaro Tech
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post #1 of 19 (permalink) Old Dec 13th, 05, 05:42 PM Thread Starter
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186 Head ???

I have a set of 69 186 heads from an SS 350-300 H/p with 194 valves,my ? is, I am going to enlarge them to 202's and I would like to know what kind of flow numbers that the 186 heads have compared to the,say,461,462 291's with 202 valves.Any help would be appreciated thanks Camaro BOB
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post #2 of 19 (permalink) Old Dec 13th, 05, 05:59 PM
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Re: 186 Head ???

Make sure the shop can make the plunge cut to "unshroud" the intake valve or else they won't flow as well as the 1.94" valves.

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post #3 of 19 (permalink) Old Dec 13th, 05, 07:49 PM
 
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Re: 186 Head ???

All those casting flow about the same.The ones with 2.02 intakes flow a little more but none flow over 200 cfm. I have flow test about a 100 diffrent heads including the 461x heads and most flow with in 10 cfm of each other.

Like gary said you must do the chamber work and the bowl area.
Just simply ploping in 1.600 and 2.02 will not do anything and will cost you flow due to the chamber wall being to close.

Going to the 2.02 and 1.600 will pick up the low lift flow and the upper flow will only increase about 3 cfm.

I have picks of a set of 461 and 291 i did i will try and post them.



Last edited by Rogers Performance; Dec 13th, 05 at 08:01 PM.
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post #4 of 19 (permalink) Old Dec 14th, 05, 01:27 PM
 
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Re: 186 Head ???

If your interested the Vortec heads flow 239 intake/147 exhaust out of the box with 1.94/1.50 valves. I have these heads on my car and "they work" Est. RWHP 475 w/100shot.
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post #5 of 19 (permalink) Old Dec 14th, 05, 02:37 PM
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Re: 186 Head ???

Mike would you be better off staying with 1.94 and 1.5 valves and doing a port and polish job?Using small stem back cut valves?You would not gain any CCs in chamber size also.

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post #6 of 19 (permalink) Old Dec 14th, 05, 02:52 PM
 
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Re: 186 Head ???

In my opion yes to a point.You want the flow co-efficent of the valve to be at 100%

You want to keep the smallest valve in the head to keep the port velocity up.

I have not seen any big improvement in flow using the under cut stem if you think about it the 11/32 part starts to come into the port when the valve opens.If you were going to use a 5/16 or 7mm stem then you would see an increase.
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post #7 of 19 (permalink) Old Dec 14th, 05, 03:09 PM
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Re: 186 Head ???

While on the subject is there a way too tell how much was removed from
a 186 head they have 2.02 1.60 valves had them cc with the spark plug
I'm going to run and they were 60 cc's.Wondering how to tell for sure
Thanks

'69 Frost Green Z/28
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post #8 of 19 (permalink) Old Dec 14th, 05, 04:06 PM
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Re: 186 Head ???

Quote:
Originally Posted by bdcole_51
I have a set of 69 186 heads from an SS 350-300 H/p with 194 valves,my ? is, I am going to enlarge them to 202's and I would like to know what kind of flow numbers that the 186 heads have compared to the,say,461,462 291's with 202 valves.Any help would be appreciated thanks Camaro BOB
Hi Bob, the 186's have (approx) 160 cc runners, as does the 041's, 461's, 462's, 291's and few others. However the "X"s which came on the Vettes averaged 171 cc's. If the valve installation is done correct, from the 1.940's to the 2.020's, they work much better, but only above 5000 RPM. Under that range there's no distinct advantage. Thanks, Gary in N.Y.
P.S. (Here we go again!) If you're interested in a POSSIBLE "heads-up" trade
with frgt. included, for a NEW set of bare Aluminum heads (200 cc runners x 2.020's x 1600's) just contact me up here or send me an e-mail me at
"[email protected]". It depends entirely on the casting dates. (Added)I'm assuming that being they're 1969 castings there are no "studs & guide plates". I can't use them if they have screw-in-studs. Thanks again.

Last edited by GOSFAST; Dec 14th, 05 at 04:13 PM. Reason: Correction
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post #9 of 19 (permalink) Old Dec 14th, 05, 04:26 PM
 
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Re: 186 Head ???

There are 2 areas on the head that can be used to measure how much could have been removed from the heads.

The first pic shows were the factory measures from for head thickness.

Most of my untouched heads from 461 to 186 castings will measure in the 1.175 to 1.180 range.As show in the second pic.

The third pick you can use the bolt hole but might not be as accurate as the first and second pic as heads are removed and put on it tends to screw this area up.

Even later castings measure close to this number.

This will also allow you to see if the head was milled on a angle.

Make sure both surfaces are clean of paint and gasket before measuring.





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post #10 of 19 (permalink) Old Dec 14th, 05, 07:05 PM
 
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Smile Re: 186 Head ???

I don't know if this means anything here, but I always kinda figured that -461/-462 heads were about 62 cc's for the 1.72"/1.50" valves, about 64 for the 1.94"/1.50" valves and my big valve -461's are 66.0 to 66.+ cc's.

pdq67



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post #11 of 19 (permalink) Old Dec 14th, 05, 07:25 PM
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Re: 186 Head ???

Sorry for hijacking this thread but why do people call Bronze Liners Bronze Guides? In my past experience and on a set of heads I have, the machinist insisted on the bronze guides not liners (as in pic above). It cost more and the heads have to be hogged-out to accept them as they are considerably thicker than the liners but I wonder if its worth having done? nBTW nice looking head work there.

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post #12 of 19 (permalink) Old Dec 14th, 05, 09:59 PM
 
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Re: 186 Head ???

[QUOTE=HOGDADDY]Sorry for hijacking this thread but why do people call Bronze Liners Bronze Guides?


Thanks for pointing that out.

Yes they are bronze liners they are about .030 thick wall.

The solid bronze guide is found more in the aluminum heads then cast iron but are used in dart and protopline cast iron heads.

Any time you repair a guide or remove one and put a new one in you run the risk of moving the center line and having the seat way off. Case in point would be a bbc head you never take out a guide in those heads if you can avoid it.

And thank you about the machine work.
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post #13 of 19 (permalink) Old Dec 15th, 05, 03:58 PM
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Re: 186 Head ???

Hi Bob, going to pass at this time on heads, (this time around), wrong dates. I believe you had another post up here about using those 186's on a 400" SB. Save your money, they won't deliver, been there, done that. Thanks, Gary in N.Y.
P.S. The heads in the trade deal are the SB "Australian's" that flow 260 CFM from the box and will make 440 HP (easy-no porting) on a 383" stroker, they are excellent "budget" heads for between $500.00/$600.00 (pair), and perform equally well on a 400" SB. One more item, the heads in the photo's (with the chamfers all chipped away) are totally repairable back to new AND original looking with NO welding. We do many on those repairs we see from resto the shop on the early SB's. Even cracks don't matter as long as they're shallow and not down to the bottom of the head. It's a very expensive repair however!
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post #14 of 19 (permalink) Old Dec 15th, 05, 07:29 PM
 
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Question Re: 186 Head ???

Gary,

Are the inexpensive Aussie SB heads you are talking about the ones I'm always mouthing about from Hotrodsusa?? I know I have been told and have looked it up, but my memory is about as long as my left hand index finger!!

I need to put this info in my new "Brains letter"....

pdq67



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post #15 of 19 (permalink) Old Dec 16th, 05, 07:00 AM
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Re: 186 Head ???

Quote:
Originally Posted by pdq67
Gary,

Are the inexpensive Aussie SB heads you are talking about the ones I'm always mouthing about from Hotrodsusa?? I know I have been told and have looked it up, but my memory is about as long as my left hand index finger!!
I need to put this info in my new "Brains letter"....pdq67
Hi pd, you're a tough act to follow sometimes (just kiddin')! Yes I believe they are and for the price (when you're on a budget) they perform as desired. The unit pictured here has a very mild cam and is totally "streetable" with no issues. 436HP and 447 Ft.Lbs. with the "Edelbrock-Scorpion"on top, we wanted to test this "old" intake on this unit. No add'l porting time "wasted" on them either, just a "quickie" clean-up. This one has 3/8 R/A studs on top. Thanks, Gary in N.Y.
P.S. If they ever release the BB's from "downunder", don't get involved (at least in the beginning) even though the price is also "right". I've been informed by one "major" warehouse they will not carry them! We are NOT talking the (Comp-Cams) Pro-Topline series here.
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