Hot Rod Forum : Hotrodders Bulletin Board - Reply to Topic
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine> Pontiac 400
User Name
Password
lost password?   |   register now

Thread: Pontiac 400 Reply to Thread
Title:
  
Message:
Trackback:
Send Trackbacks to (Separate multiple URLs with spaces) :

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Additional Options
Miscellaneous Options

Topic Review (Newest First)
05-19-2013 09:00 PM
77pontolds
400 pontiac

The engine responds better now, thanks to the demon. It has a pertronics hei dist, but is otherwise stock 71 in a 77. My parts car is a 80 turbo TA, and I'm interested in finding a new home for it. It has a 400 in it now , which I plan to keep for a spare for my car.
05-19-2013 09:23 AM
Mr. P-Body I doubt the intake helped anything but weight, as the factory intakes are excellent (yes, even the EGR units). But I'm glad you're happy! THAT is what it's all about!

Keep on Yakkin! (that's Ponti-YAKKIN!)

Jim
05-18-2013 10:06 PM
77pontolds
Quote:
Originally Posted by hcompton View Post
Glad to hear it. Do you have alum intake and hei? Your set to enjoy. They dont need much to be fun.

The 400 will not show a stock 403 trans much respect. If you havenet already best to have a great trans built next. That should be the next biggest drop in et for single improvment.

Not sure what purpose the 403 was built for but it was not performance or tq. it was not all that strong compared to the beating a new 400 will take. So not even sure why they built then. The 350 from olds and chevy and pontiac was comparable and had advantages. I just dont see the advantage to the 403. Most of gm products have a perfect nitch where they belong and were properly designed to work great at doing.
Hello again, I have a edelbrock performer intake, and now a Demon 725. It runs real good!!!
01-21-2013 08:48 AM
Mr. P-Body Can't say 100% sure, but what I recall, the 403 was already approved by CARB (California Air resource Board) and the Pontiac was not. It was less expensive for GM to use the line data in other assembly plants, than to recertify the Pontiac for California. At the time, they weren't too concerned with selling actual performance cars as they were selling the "image" of performance. That's was the great era of "sheeps in wolf skin". You remember. All the "scoops" weere closed up, cataytic converters were choking things, vacuum lines everywhere... Hey, Chevy even got into the act with a "NACA" or "Douglas" scoop that was nothing more than a sticker on the hood of the revived (due to T/A sales) Z/28.

In '79. my brother and I went to various dealerships and test-drove all the "performance" offerings. The ONLY car we found rfom GM that would truly turn the tires over from a "standing start" were the T/As. But we had to go to Arizona to find them! A stock 403 car came with TH350, no other option. It wouldn't turn them. A '79 Corvette in Cal, also had TH350 as the only trans. It too wouldn't turn the tires over. -We DID find a 400/4-speed T/A at Mecham Pontiac (yes, the infamous governor, actually pretty nice guy and honorable business man) in Glendale, AZ. IT would rip the tires! Nobody had a '79 Corvette with a manual trans available for a test drive.

FWIW

Jim
01-19-2013 07:05 PM
hcompton
Quote:
Originally Posted by 77pontolds View Post
Wow! You folks were right. The 400 Pontiac makes my Firebird haul 555. It makes me want to put casters on the rear. It is quite a difference from the Olds 403. Now I have to be careful when I nail it, cause when it shifts into second gear, it wants to go sideways. Fun!!!
Glad to hear it. Do you have alum intake and hei? Your set to enjoy. They dont need much to be fun.

The 400 will not show a stock 403 trans much respect. If you havenet already best to have a great trans built next. That should be the next biggest drop in et for single improvment.

Not sure what purpose the 403 was built for but it was not performance or tq. it was not all that strong compared to the beating a new 400 will take. So not even sure why they built then. The 350 from olds and chevy and pontiac was comparable and had advantages. I just dont see the advantage to the 403. Most of gm products have a perfect nitch where they belong and were properly designed to work great at doing.
01-19-2013 02:16 PM
LATECH 77pontolds.... Good going congratulations on the finish up of your engine.
Glad to hear that you got lots of torque from that baby.
Enjoy.... LA Tech
01-19-2013 10:08 AM
cobalt327
Quote:
Originally Posted by hcompton View Post
Lol how old is that article. They dont even make those 3 tubes any more. My three tubes from headman were way better than any manifolds and a few of the four tubes i tried.
So you're telling me you did back-to-back tests, w/ONLY the headers being changed? And you lost power w/which 4-tube headers?

More to the point, I DID have occasion to test 3-tube Hedman aluminized "headers" against a set of Hedman 4-tube headers on a 400 Pontiac belonging to my friend and neighbor, Bill Anderson. '78 T/A, engine I built, had a cam from HO, #12 heads. It picked up 1.5 tenths- WITH ABSOLUTELY NO OTHER CHANGES, other than the runs were made one week apart. I'll be glad to give you his email addy should you doubt me.

When you learn why a 4-tube header works better than a shortie/block hugger/3-tube header, get back to me. Has to do w/the scavenging effect that a 4-tube has that's disrupted when using a 3-tube. The age of Hand's article is irrelevant- what's relevant that you choose to ignore is the big tube never "peaks", and if it DID, the rpm would be too high for the smaller pipes.
01-19-2013 08:34 AM
Mr. P-Body Regarding flow and low-speed power, headers aren't really in their "natural habitat". I have no doubt, the three tube cheepies made more "seat of the pants" power than the log manifolds. I also have no doubt, on a dyno, the Ram Air exhaust manifolds make more power above 3,500 RPM than the 3-tube jobs. There is no way they can make more peak power than a good 4-tube header unless something is terribly "amiss" elsewhere.

Headers are not installed specifically for "flow" increase. The sound wave plays an important role in making peak power. Isolation of exhaust pulses from each other, and the length of the primary tube, have the greatest impact on power production from headers. The BIG difference would show clearly at a track with "open" headers.

77pontolds,

Glad you got the 'bird going! Olds guys always get defensive when I tell them this about the 400 Pontiac. But it's true. Not many better street-performance engines than 400 Pontiac. Wait 'til you pump it up a little... (:- Ignore the buzzing in your ear about Chevys. If it were a Camaro, I'd agree with a Chevy... T/A and GTO were the top of their respective classes for a lot of reasons.

Jim
01-19-2013 06:53 AM
hcompton
Quote:
Originally Posted by cobalt327 View Post
Don't believe me? Fine. What if Jim Hand said the same thing?

Building a Strong Street Machine - Part 12
Lol how old is that article. They dont even make those 3 tubes any more. My three tubes from headman were way better than any manifolds and a few of the four tubes i tried.

Fyi hooker 1 3/4 long tubes are not the same price as the 3 tubes about 100 bucks cheaper and only a few hp down.

Just depends if the cost and clearence are worth it for the four tubes.
01-18-2013 09:19 PM
cobalt327
Quote:
Originally Posted by 77pontolds View Post
Wow! You folks were right. The 400 Pontiac makes my Firebird haul 555. It makes me want to put casters on the rear. It is quite a difference from the Olds 403. Now I have to be careful when I nail it, cause when it shifts into second gear, it wants to go sideways. Fun!!!
Good deal! Must be running good- the Olds 403 usually is no slouch up to at least 4500 or so (stock). Stay safe out there and enjoy.
01-18-2013 09:16 PM
cobalt327
Quote:
Originally Posted by hcompton View Post
They gave more hp and tq than any of the four tubes with in a hundred bucks.
Don't believe me? Fine. What if Jim Hand said the same thing?

Building a Strong Street Machine - Part 12
01-18-2013 09:03 PM
77pontolds
Pontiac 400

Wow! You folks were right. The 400 Pontiac makes my Firebird haul 555. It makes me want to put casters on the rear. It is quite a difference from the Olds 403. Now I have to be careful when I nail it, cause when it shifts into second gear, it wants to go sideways. Fun!!!
01-10-2013 02:22 PM
hcompton
Quote:
Originally Posted by cobalt327 View Post
Better than nothing I suppose, but not a 4-tube.
They gave more hp and tq than any of the four tubes with in a hundred bucks. Even the guy at jegs confirmed that unless you going with full length 600 headers these are with in one or 2 hp higher or lower of just about all the cheap headers on the market. They really out performed a lot of the cheap hooker and other four tube headers. But once you got into good flowing stainless headers they were out shined. With a sbc small runner work well but the big poncho like the flow. 1 5/8 inch primaries and 2 inch for the double is plenty big enough. The center cylinders dont fire right on top of each other so no real need for a bigger tube. I think its more for fit then anything else.

Since the two center ports are so close to each other headers dont actually fit well unless they have the pipes flatted to fit the ports. And with cheap 4 tubes they just weld em on and ship it when you look from the valve out you can see the pipe does not properly cover the ports if the pipes are circular.
01-10-2013 02:12 PM
cobalt327 Better than nothing I suppose, but not a 4-tube.
01-10-2013 09:25 AM
hcompton
Quote:
Originally Posted by 77pontolds View Post
I haven't had a chance to lean into it yet because of the snow, but I think it will be pretty impressive. It has 3.73 rear end gears, a 200-4R auto, and a 625 Carter AFB. I'm going to try out a 750 Demon to see if it makes any difference, since it would be a loaner to check out. More later, Next it goes to the body/paint shop for a freshen-up, and to get rid of the hail damage. Thanks, Uncle Rich
I used a set of headmen 3 tube headers for my stock engine and it was way more power than stock manifolds and a lot cheaper than four tubes. also its the most power for the buck with headers. cheap four tubes make less and expensive ones are just that expensive.

3 Tubes use the center pipe is larger and covers both center ports. Sounds like its going to be junk but works perfect for near stock builds. Or even ones with a few updates. It gives long tube power for cheap header prices. Headman also makes them to fit most cars. I did have to smack a dent in mine to make it fit but that was no big deal since it ran way better than the manifolds. They did rust up really fast. But for the price paint is not an issue.

Part number for headmans is 28140 they have them to fit most ponchos.
This thread has more than 15 replies. Click here to review the whole thread.

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -6. The time now is 05:26 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.