Author Topic: Pontiac 400-455 Questions and answers. Subthread  (Read 153779 times)

nhirschi

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #200 on: September 18, 2015, 12:54:45 PM »
question.im interested in putting an olds 455 in my 79 firebird,but would a 454 be a better engine in general and for getting parts.

chief poncho

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #201 on: September 18, 2015, 05:42:07 PM »
Better is a relative word.  Parts for a big block chevy (BBC) are generally more readily available and cheaper than a Buick, Olds or Pontiac (BOP) engine.  However, today's aftermarket is really strong allowing BOP engine builders lots options.

Why not go with a Pontiac 400 or 455 instead of an olds 455? Depending on the level of build, the Poncho mill probably wouldn't run much more than a similarly built BBC.  Honestly if you're open to other alternatives, an LSx conversion would probably make the most sense.  While it will require a bit more work, you end up with a modernized combo that will give you better power options, driveability and fuel economy. 
1971 Lucerne Blue Trans Am (455HO, Automatic) - currently my project car.
Previously Owned TA's/Musclecars: 2002 Pewter WS6/M6 Trans Am, 1968 Dodge Superbee 383/4speed,  1975 TA 455/4speed, 1989 Mustang LX 5.0/5speed, 1980 TA Indy Pace Car, 1977 TA 400/Auto, 1989 GTA 350TPI, 1990 GTA 350TPI, 1986 IROC 305TPI, 1989 Mustang LX 5.0/Auto, 1993 Mitsu 3000GT VR4 (and probably a few I've forgotten about)

EvilEdOlean

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #202 on: October 07, 2015, 10:16:34 AM »

Posted - 05 Oct 2015 :  08:58:52 AM  Show Profile  Email Poster  Edit Reply  Reply with Quote  Delete Reply
Finally got me an engine cylinder compression tester and tested
Compression in each cylinder. Below results show the cylinder # Dry and wet test readings
1 D 141 W 185
3 D 132 W 162
5 D 130 W 225
7 D 141 W 230
2 D 137 W 195
4 D 81 W 129
6 D 30 W 42
8 D65 W 100
Could be a bad head gasket on the driver side block, three cylinders on the same head 4,6,8 with low compression and the middle one the lowest and worst. Wet test on #6 should have been higher also. This may also explain why the radiator water was bubbly the second time I started the engine and did not look right. I think the engine overheated and blew out. Looks like I'm gonna be taking the passenger side Cylinder block off. Oh what fun, I not done this since 1980. Maybe next weekend.
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Facebook:
SPCC Facebook Group discussion, buy sell trade. 
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Email: Southwest Pontiac Car Club
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EvilEdOlean

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #203 on: October 11, 2015, 10:16:46 AM »

Posted - 05 Oct 2015 :  08:58:52 AM  Show Profile  Email Poster  Edit Reply  Reply with Quote  Delete Reply
Finally got me an engine cylinder compression tester and tested
Compression in each cylinder. Below results show the cylinder # Dry and wet test readings
1 D 141 W 185
3 D 132 W 162
5 D 130 W 225
7 D 141 W 230
2 D 137 W 195
4 D 81 W 129
6 D 30 W 42
8 D65 W 100
Could be a bad head gasket on the driver side block, three cylinders on the same head 4,6,8 with low compression and the middle one the lowest and worst. Wet test on #6 should have been higher also. This may also explain why the radiator water was bubbly the second time I started the engine and did not look right. I think the engine overheated and blew out. Looks like I'm gonna be taking the passenger side Cylinder block off. Oh what fun, I not done this since 1980. Maybe next weekend.

]Well got the passenger side head off yesterday, the number 8 and 2 piston were both hitting the combustion chamber on the head. Can anyone tell me how this can happen? I am assuming bad rod bearings or crankshaft bearing? I brought each piston to TDC and pushed down on them, Hearc a click when i pushed down but it did not appear to be any major gaps. Will pull off the driver side today to see if I have any of the same damage over there. Pushrods and valves all looked good. Number 8 cylinder chamber has some deep groves the head underside some deep pits now, At lease I know know have the 6x number 4 heads, if they are salvageable that is not known. Wish I knew how to post pictures here?

Link to photos below!!!!
http://s989.photobucket.com/user/Edward_Ozogar/library/
« Last Edit: October 11, 2015, 01:26:13 PM by EvilEdOlean »
Web site under construction at:
Southwest Pontiac Car Club
http://edozogar.wix.com/el-paso-swpcc

Facebook:
SPCC Facebook Group discussion, buy sell trade. 
https://www.facebook.com/groups/El.Paso.Trans.Am.Club/
SPCC - Facebook Community page
https://www.facebook.com/SouthwestPontiacCarClub/

Email: Southwest Pontiac Car Club
spcc.elppasotexas.gov

77TAfromMO

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #204 on: March 17, 2016, 06:39:14 PM »
So a local engine builder I know has a 1971 455 engine that I am going to go have home build. Crank condition is unknown so but the time mag it and do any other work I we can buy a new forged crank. Since price does not seem to vary much between stroke lengths considering maybe going as up to 4.5" stroke. Anyone running this stroke crank or should I stay with with a 4.25 or 4.21. Curious what your combo might be and performance numbers.
1977 Brentwood Brown TA 400 Auto

Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #204 on: March 17, 2016, 06:39:14 PM »

gs462

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #205 on: November 17, 2016, 09:37:07 AM »
Hi, guys I'm new to Pontiacs. Can you tell me what is the best  production head to use on a 461 stroker. the heads will be fully ported but id like to start with the best flowing factory head.


Thanks.

oldskool

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #206 on: November 17, 2016, 12:49:02 PM »
"...tell me what is the best  production head to use on a 461 stroker..."


The best reasonably priced iron heads, for a pump gas stroker are the 6x-8 & 6x-4 heads. The 5c-4 & 5c-8 heads are nearly identical, but much less common. The 6x heads were used on '75 thru '79 models. Therefore they are quite common and still sell for a reasonable price.

The round port heads such as Ram Air IV, 455HO, & SD455 flow better, but are now VERY pricey. :(
« Last Edit: November 17, 2016, 01:00:07 PM by oldskool »

oldskool

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #207 on: November 17, 2016, 12:54:40 PM »
So a local engine builder I know has a 1971 455 engine that I am going to go have home build. Crank condition is unknown so but the time mag it and do any other work I we can buy a new forged crank. Since price does not seem to vary much between stroke lengths considering maybe going as up to 4.5" stroke. Anyone running this stroke crank or should I stay with with a 4.25 or 4.21. Curious what your combo might be and performance numbers.

If & good condition & ground correctly the 455 crank is just fine. But, if you go to an aftermarket forged crank, I'd stay with either a 4.21 or 4.25 stroke. A 4.50 stroker will have too much low end torque for a street car, with hard tires. Just a waste of power. IMO

A 4.21 stroke engine, with 6x heads, and a decent HFT cam can easily make near 400hp, at 5000rpm, & 500ft lbs of torque, down in the 3000-3500rpm range. Of course, more power is easily obtainable, with head and/or cam upgrades.
« Last Edit: November 17, 2016, 12:59:00 PM by oldskool »

chief poncho

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #208 on: November 17, 2016, 01:59:18 PM »
Well when you say production, do you mean readily available or are you open to more rare and thus expensive alternatives. 

Best flowing Pontiac head ever is the RAM AIR V head, but good luck ever finding any not to mention exhaust and intake manifolds.  These also were only available over the parts counter at dealerships and were never installed on a production line car.

Best flowing cast iron head is the 73 and 74 SD455 heads, cast number 16/x, but again, you'll pay a fortune for these.  Any round port Ram Air II/IV or HO head will outflow all other D-port heads, but again are going to be very expensive and not worth the money when compared to an aftermarket aluminum head.  RAII and IV are going to have small combustion chambers and put your CR over 13:1 unless you dish the pistons.  The later '71 and '72 HO heads have large combustion chambers and will drop your CR down to around 8.5:1.  See the following link for the cast numbers http://www.wallaceracing.com/head1.htm.

Now for real options using factory cast iron heads that are readily available and affordable, I would look at the '71 and '72 400 4bbl heads cast number 96 and 7k3, followed by maybe the 6x-4.  Any of these would make a good place to start.

But in all honesty, unless you know someone that knows how to port the heads and they are doing it for free or little money, I would move right past the factory Pontiac heads and go with the Edelbrock or Butler heads.  You can get either D-port or Round Port designs.  By the time you buy a decent core, have all the machine work performed, plus replace components the aftermarket heads will more than likely outperform them right out of the box.  With porting, the aftermarket heads will far outperform pretty much any factory head.

1971 Lucerne Blue Trans Am (455HO, Automatic) - currently my project car.
Previously Owned TA's/Musclecars: 2002 Pewter WS6/M6 Trans Am, 1968 Dodge Superbee 383/4speed,  1975 TA 455/4speed, 1989 Mustang LX 5.0/5speed, 1980 TA Indy Pace Car, 1977 TA 400/Auto, 1989 GTA 350TPI, 1990 GTA 350TPI, 1986 IROC 305TPI, 1989 Mustang LX 5.0/Auto, 1993 Mitsu 3000GT VR4 (and probably a few I've forgotten about)

gs462

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #209 on: November 17, 2016, 08:29:38 PM »
I appreciate the replies, My buddy did head porting for a local race shop for 30+ years, so the port work and the valve job wont cost me anything. What do you guys think of the 670 head?
« Last Edit: November 17, 2016, 08:33:13 PM by gs462 »

chief poncho

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #210 on: November 17, 2016, 10:43:07 PM »
The 670 head would be great on a 400, but even then the compression is pretty high.  With the 72cc combustion chambers it'll bump your static compression over 12.5:1 or more.  I would stay away from any pre-70 389/400/428 head or you'll have exactly the same problem.  If you can find them, and they are expensive some 1970 455HO d-port heads wouldn't be bad either, they are cast number 64, but again are more expensive than some of the other options posted.  Take a look at the link to Wallace.  It lists the engine, year, cast number, valve size, and chamber size for most heads.

Here are some other options from that list:

1970 15's 87cc but small valve press in studs.
1973 4x or 4c but be careful about combustion chamber size some 4x's were 98cc and others 114cc
1975 5c but you will have to have the studs drilled and tapped otherwise live with the pressed in stock pieces.

If you wanted to go with recessed pistons, you could probably use the 670's or other small chamber heads. 
1971 Lucerne Blue Trans Am (455HO, Automatic) - currently my project car.
Previously Owned TA's/Musclecars: 2002 Pewter WS6/M6 Trans Am, 1968 Dodge Superbee 383/4speed,  1975 TA 455/4speed, 1989 Mustang LX 5.0/5speed, 1980 TA Indy Pace Car, 1977 TA 400/Auto, 1989 GTA 350TPI, 1990 GTA 350TPI, 1986 IROC 305TPI, 1989 Mustang LX 5.0/Auto, 1993 Mitsu 3000GT VR4 (and probably a few I've forgotten about)

gs462

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #211 on: December 01, 2016, 08:58:34 PM »
Chief thanks for the answers Im a complete noob when it comes to Pontiacs. Can you tell me what the max stroke my 400 block will take before I have to do major clearance work??

chief poncho

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #212 on: December 02, 2016, 05:20:38 PM »
I don't know what the limitation is, but there are several aftermarket stroker kits for the 400 that'll put you at about 4.21.  I believe those kits come with cranks that are machined to fit without modifying the 400 block.  Keep in mind a factory 421-455 crank won't work in a 400 unless you have the main journals turned down to 3.00" vs the 3.25" 421-455 size. 

Looks like Butler sells kits that go up to 4.5" stroke!  I don't know if those require machining, but most likely would.

http://butlerperformance.com/c-1234863-engine-components-internal-rotating-assemblies-stroker-kits-400-blocks-406-495-cu-in.html
1971 Lucerne Blue Trans Am (455HO, Automatic) - currently my project car.
Previously Owned TA's/Musclecars: 2002 Pewter WS6/M6 Trans Am, 1968 Dodge Superbee 383/4speed,  1975 TA 455/4speed, 1989 Mustang LX 5.0/5speed, 1980 TA Indy Pace Car, 1977 TA 400/Auto, 1989 GTA 350TPI, 1990 GTA 350TPI, 1986 IROC 305TPI, 1989 Mustang LX 5.0/Auto, 1993 Mitsu 3000GT VR4 (and probably a few I've forgotten about)

gs462

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #213 on: December 04, 2016, 06:37:29 PM »
I don't know what the limitation is, but there are several aftermarket stroker kits for the 400 that'll put you at about 4.21.  I believe those kits come with cranks that are machined to fit without modifying the 400 block.  Keep in mind a factory 421-455 crank won't work in a 400 unless you have the main journals turned down to 3.00" vs the 3.25" 421-455 size. 

Looks like Butler sells kits that go up to 4.5" stroke!  I don't know if those require machining, but most likely would.

http://butlerperformance.com/c-1234863-engine-components-internal-rotating-assemblies-stroker-kits-400-blocks-406-495-cu-in.html

Thanks that is what I was wondering Id like to make the most cubes I can so as to make the most power while still looking stock.

Rapp79

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #214 on: August 07, 2017, 07:02:49 PM »
I'm new to the forum so sorry If I've messed something up posting. Anyway, I'm in the process of swapping the transmission and 403 for a new th350 and a Pontiac 400 I'm currently having built. The previous owner had some issues with it where coolant got into the tranny fluid and the motor was pretty bad. I fixed most of the oil leaks, redid the intake manifold gaskets and fixed the brakes. I got it good enough to drive and I drove it to school my whole senior year of highschool while restoring as much of it as I could. Anyway, I was curious what all I could use off of the 403 on the 400. I'm planning on driving to college and it's about a 25 mile trip one way so I was also curious if it would be too much for the 'ol girl. The body and frame are all solid but as soon as I swap the motor I'm planning on putting in new socks and rebuilding the suspension to make it a little more smooth.

Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #214 on: August 07, 2017, 07:02:49 PM »



70RAIV455

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #215 on: August 07, 2017, 07:25:49 PM »
I'm new to the forum so sorry If I've messed something up posting. Anyway, I'm in the process of swapping the transmission and 403 for a new th350 and a Pontiac 400 I'm currently having built. The previous owner had some issues with it where coolant got into the tranny fluid and the motor was pretty bad. I fixed most of the oil leaks, redid the intake manifold gaskets and fixed the brakes. I got it good enough to drive and I drove it to school my whole senior year of highschool while restoring as much of it as I could. Anyway, I was curious what all I could use off of the 403 on the 400. I'm planning on driving to college and it's about a 25 mile trip one way so I was also curious if it would be too much for the 'ol girl. The body and frame are all solid but as soon as I swap the motor I'm planning on putting in new socks and rebuilding the suspension to make it a little more smooth.
Just the starter motor & The Alternator.

Grand73Am

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #216 on: August 07, 2017, 07:57:57 PM »
I agree that the starter and alternator are about all you can use from the 403. You could have used the th350 that was on the 403, since it fits the 400 too. The motor mounts on the frame are the same if you wanted to re-use them, but they don't cost much so when swapping an engine, it's usually preferable to put new ones in.
If you have a/c, the compressor is the same, but the mounting brackets are all different.
Steve F.

Rapp79

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #217 on: August 07, 2017, 09:41:52 PM »
I agree that the starter and alternator are about all you can use from the 403. You could have used the th350 that was on the 403, since it fits the 400 too. The motor mounts on the frame are the same if you wanted to re-use them, but they don't cost much so when swapping an engine, it's usually preferable to put new ones in.
If you have a/c, the compressor is the same, but the mounting brackets are all different.
Thanks! good to know. I was thinking the water pump pulley would be the same since they look fairly similar but just to be safe I'll order one specifically for a 400. I'm putting in a new transmission since the old one was pretty hashed from the previous owner completely neglecting to flush the contaminated transmission fluid when his radiator leaked into the tranny cooler. I flushed it but it was starting to have a delay going into reverse and it's slipping gears so I got another one. The frame motor mounts are actually in pretty good shape so I'll reuse them. The A/C and heat were deleted by the previous owner so I don't have to worry about those. Other than the water pump pulley I think I'm all set with parts for the swap. Thanks again!
« Last Edit: August 07, 2017, 09:51:39 PM by Rapp79 »

Calamity

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #218 on: March 07, 2018, 02:02:00 PM »
Looking to remove my heater and A/C unit, going to be a fair weather car, and looking for pictures on routing the house from the water pump to the back of the head. Anyone got anything? Its the 400 engine.

Dusty Bird

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #219 on: November 14, 2018, 07:53:20 PM »
Hello All

Been along time since my last post, sorry.

My Question:

Has anyone installed the LONG BRANCH exhaust manifolds on a 1970, 2nd Gen Firebird????

I have a 1970 and I really like the look of the LONG BRANCH Manifolds.

If you know anyone or have any picture's that would help a lot too.

Why is it that they say they won't fit???

Any Help would be GREATLY APPRECIATED.

Thanks In Advance for any help or information.

Take Care All

Dusty



stitcher

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #220 on: April 05, 2019, 08:55:59 PM »
Since the blocks seem to be the same, can a 350 block be bored and stroked to a 400 or 455 cu. in.?

oldskool

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #221 on: April 06, 2019, 09:30:11 AM »
Since the blocks seem to be the same, can a 350 block be bored and stroked to a 400 or 455 cu. in.?

They can definitely be stroked using the 4" & the 4.25" stroke cranks. Cubes will range from 383 to 413, depending on bore size. Butler offers both rotating assemblies.

https://butlerperformance.com/i-24591337-butler-performance383-388ci-balanced-rotating-assembly-stroker-kit-for-350-block-4-000str.html?ref=category:1234861

https://butlerperformance.com/i-24591338-butler-performance407-413ci-balanced-rotating-assembly-stroker-kit-for-350-block-4-250str.html?ref=category:1234861

The casting number 500810 blocks have the thin main webs, like the 557 400 blocks have. So, I wouldn't build a stroker with a 500810 block. Any other good 350 block should work OK. Max safe bore will depend on core shift, internal corrosion, etc. Some Pontiac blocks can be bored .070 or more. Some won't even safely bore .060. A competent machine shop can check the cylinder walls for thickness, to determine max safe bore size.

Especially if you use heads with 2.11/1.77 valves, you'll need valve clearance chamfers, which some call "notches", at the tops of all the cylinders. This valve clearance is needed for what some called valve "unshrouding", to allow good flow. Can also allow the use of a larger cam. These chamfers can be added to any block, using a hand grinder, such as those used for head porting. Obviously, they need to be in the correct locations, and of the correct size.   

72blackbird

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Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #222 on: May 22, 2019, 12:09:36 PM »
I build so many 400s, 455s, and 461s it almost get boring- a 350p with a 4" stroke, 6.8 BBC rods would make for a nice Poncho w/ good torque too.

350Ps are plentiful, but as mentioned that small bore does require chamfers to let you use big valve heads with it.

Geno
1977 SE T/A (sold :( )
1974 455 T/A (sold :( )
1972 Esprit restomod
1976 T/A restomod
1975 Formula 400 4-speed donor car
1978 Martinique blue W72 4-speed T/A, hurst tops

Re: Pontiac 400-455 Questions and answers. Subthread
« Reply #222 on: May 22, 2019, 12:09:36 PM »
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