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Old 10-31-2006, 12:27 PM
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1968 pontiac heads

Did pontiac ever make a high out put head for a 350v8 with ac.At this time I have the 2brl low performance motor.

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Old 10-31-2006, 01:06 PM
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Yes, they made a 350HO (320 hp) which had #18 heads. Standard should be #17 on the center port. but I believe the compression and cam were different as well, not just the heads.
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Old 11-01-2006, 05:47 AM
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Do some searching on the net. Most any Pontiac cylinder head will work on your 350. Same block as the 326, 389, 400, 421 & 455. I don't see you making a lot more power with a stock type head swap. More trouble then it will be worth in my book. I would suggest finding a decent 455 to put in your car. Yank the stocker and keep it for posterity.
Mark
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Old 11-01-2006, 02:32 PM
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I don't know that I'd jump straight to big cubes. I ran a 350 HO for years and loved it. Beat my share of mouse motors with it.
320 hp from a stock 350 ain't to shabby.

Not sure why so many jump straight to the 455 for the Pontiac when other makes build up the small blocks.
A well built Pontiac 350 or 400 is a good runner for the street. The bigger journal on the 455 hurts the rpm's but it does make gobs of torque.
You can build a 455 out of a 400 using a turned 455 crank. Little more to it than that but it gives you a better winding injun.

Here's the HP run down of 68 Pontiacs
1968
350/265
350/320 H.O.
400/265
400/350
400/360 H.O.
400/360
(Ram Air)
400/366
(Ram Air II)
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Old 11-02-2006, 04:58 AM
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Quote:
Originally Posted by 428ho
Not sure why so many jump straight to the 455 for the Pontiac when other makes build up the small blocks.
A well built Pontiac 350 or 400 is a good runner for the street. The bigger journal on the 455 hurts the rpm's but it does make gobs of torque.
You can build a 455 out of a 400 using a turned 455 crank. Little more to it than that but it gives you a better winding injun.
Bigger cubes just makes more torque... Torque is king for a street motor and a mildly built 455 will walk all over a radical 350 any day. The small block Versus Big block analogy doesn't apply to PONTIAC motors. The "PONTIAC" 350 is a big block. The block is no different from a 455 other then bore size and crank journals as you mentioned.
I have run both myself and much preferred the tamer 455 over the wild 350. Much easier to drive, better vacuum for power brakes and the slight loss of upper RPM's isn't even noticed as the race is usually over before it's an issue. Just my thoughts. I put a lot of money into a 350 and had a faster 455 for much less...
Do a search on the site. There have been a lot of threads devoted to Pontiacs and there is a lot of info already available.
Mark

Last edited by astroracer; 11-02-2006 at 05:04 AM.
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Old 11-02-2006, 06:52 AM
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Just so it's here- manufacturers do make stroker kits for the poncho blocks, turning the 400 into a 455. That way you don't have to find a 455 crank and get it turned, you likely would need it cleaned up and balanced but...
Also, in theory, if you wanted something different just to be different a poncho 350 could get stroked to a 400 using the same 455 crank in a xxx block trick. It's something I've thought about doing for a while, but I don't know anyone who has done it so take it for what it's worth.
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Old 11-02-2006, 07:22 AM
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I wasn't referring to Pontiac as a small block. The other guys build their small blocks. A 350-400 Chevy is still equal to a 350-400 Pontiac in cubic inches, not physical block size.
I guess a lot of people do go to the 455 since it is a bolt in swap. But depending on the 455 you may actually lose HP over a stock HO 350

I like the 455 but for street use I'm not sure I'd what that many cubic inches on a daily basis.
Just like you see a lot of small block cars of other makes, big inches isn't everything. Well, so they say

Right now I have a fairly radical 400 and while it was a blast to drive (it's in restoration right now) when I was running the HO 350 the car was more enjoyable as a driver. All I did was add an aluminum intake, holley and headers and the 350 really came alive.

If I was building for street/strip use then I might go big. The original poster never stated where he was going with his engine.
Seems this thread took a little detour when all he asked was about a 350 head.

I agree somewhat about cubes vs rpms, but depending on the engine you find you'll still have to go inside to boost the cam and compression or make a cam and head swap.

Notice the HP fall off of later Pontiac engines, mainly due to lower compression and anemic cams. Some later heads had way to open a chamber as well.

1971
350/250 hp
400/265 hp
400/300 hp
455/325 hp
455/335 hp H.O.

1972
350/160,175 hp
400/200 hp
400/250 hp
455/220 hp
455/250 hp
455/300 hp H.O.

1973
350/150, 175 hp
400/170, 185 hp
400/200, 230 hp
455/215, 250 hp

1974
350/155, 170 hp
350/170, 185, 200 hp
400/175, 190 hp
400/200, 225 hp
455/215, 250 hp
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Old 11-02-2006, 11:06 AM
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Here is an article Car Craft published on a built up 350 Poncho....
http://www.carcraft.com/techarticles..._pontiac_350s/
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Old 11-02-2006, 11:34 AM
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Nice link Auto.

I have another #17 head '68 Pontiac 350 sitting in the corner, been wondering what to do with it.
Hmmm, set of Edlebrocks, new slugs, cam, rollers...

Wonder if the wife would notice the difference between a built 350 over the stock OHC 6 in the convertible bird?
Maybe best to just keep the hood closed?
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Old 12-21-2006, 02:21 PM
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I would really like to build my base 68 firebird as close to an HO as possible.Does any one know were I can find 350 ho heads that take ac.I would like to put ram air heads on but have been told that they were never built to take ac?All your comments have been very helpful as this is first time I have
restored a vech in twenty years.Parts are a little harder to get this time around.I live in the northwest (Seattle).
Thanks!!
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Old 12-21-2006, 03:01 PM
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Is it true that no factory pontiac 455 ever had a taller deck than the rest of the pontiac V8 line? I always understood that from 326-455 had the same deck height. However, I believe that I read some wrong information on some web site recently that said the 455 had a higher deck height. Also, what about the 287 and 316, are they the same deck heights as all the rest of the V8's? Finally, the 336, how many of those were made? I did a search on the internet and on ebay and don't see much information about them.
This spring/summer I am planning on building at least 3 T's to sell. Each one will have a mild 350 Buick, Olds, and Pontiac in it with 200R4 for a trans. This should be interesting.
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