pontiac 400

[blackout5.3]

i have a 1977 trans am and it has a pontiac 400, i want to make some horse but im not going after a lot mid 350-370 maybe more i just want a cruiser.
every one says stroke it, but seems no one wants to help with any suggestions i just want to get away from the base 215hp and take some of that 20,000flbs of torque turn to horse LOL. i already have a weiand action plus intake, headers and a holly 750. any suggestions wich cam and crank to choose, and modifications to the heads i need to make for the stroke? or if it is needed.

[snaggeltooth]

A good port and polish on the heads will do good . you have the Ram air cams . I say the 3 , the ram air 4 can make a few more horses but the 3 is smother .. Up your compression to 10 and you should be good to go ....

[jonszo6]

I have a 1970 Pontiac GTO with the 400 rated at 350 horse and mine got a nice little boost by adding roller rockers...

[blackout5.3]

thanks guys, i have toyed with the idea of roller rockers and wondered what they would do, but i got a little suprise today, i hadent recieved the 400 yet when i posted last night, and when i picked it up today and took it to a friends house he said it was a olds403 not a 400.:flex:

[jerry caesar]

just out of curiousity, is your trans am a automatic car?

If you truly have a 403 in your hands, go on car crafts website and do some searching, over the past year I remember them doing something with the 403.
quick 403 links
realoldspower.com
http://www.mondellotwister.com/Art403Olds.htm
http://www.mondellotwister.com/ArtUnsungH.htm

Car crafts street buildup of a pontiac 455, do same with 400.

http://www.carcraft.com/techarticles/116_0306_pont/

[Zboner]

im about to build a 400 with a friend here shortly when it gets out of the machine shop and back to him, get the casting numbers off the heads, i think the 6x heads are the best for the 400's if im not mistaken

[jerry caesar]

there is an earlier head, which i cant think of off the top of my head, that has a smaller cc than the 6x, to bump compression on later low compression motors. But I have no idea what kind of 400 setup your going to do, stock pontiacs used flat top pistons and varied the compression with the combustion chamber design.

[Zboner]

i know ther compression is something stupid if your going to do a NA set up i think the 400's are like 7.5/1 or something or 8, but perfect for a supercharger!!!

[snaggeltooth]

if it is a 403 it will have the oil filler tube in the front of the engine Pontiacs fill through the valve covers http://i76.photobucket.com/albums/j16/snaggeltooth/81taeng3.jpg

[0to60n4.5]

A 403 is not nessasarily(sp) a bad thing . They make cams - heads - headers and such for them.

I have a 10.5 to 1 CR , port fuel injected one in my 79' Cadillac Seville that runs pretty good.

Back in the day - 20 years ago it was a fast 4 door. Now the factorys put out Sedans that will run circles around it.

[blackout5.3]

if it is a 403 it will have the oil filler tube in the front of the engine Pontiacs fill through the valve covers http://i76.photobucket.com/albums/j16/snaggeltooth/81taeng3.jpg


lmao looks like mr car guiru was wrong, Gawd i look foward to telling him, but it deffinatally fills through the valve covers not through a tube.

[blackout5.3]

just out of curiousity, is your trans am a automatic car?

If you truly have a 403 in your hands, go on car crafts website and do some searching, over the past year I remember them doing something with the 403.
quick 403 links
realoldspower.com
http://www.mondellotwister.com/Art403Olds.htm
http://www.mondellotwister.com/ArtUnsungH.htm

Car crafts street buildup of a pontiac 455, do same with 400.

http://www.carcraft.com/techarticles/116_0306_pont/

yes it is automatic, and im going back with a 700r4 so i will have OD for long hauls to shows

[blackout5.3]

im about to build a 400 with a friend here shortly when it gets out of the machine shop and back to him, get the casting numbers off the heads, i think the 6x heads are the best for the 400's if im not mistaken

aight, let me know what you find out, im all about getting more out of less

[jimmyblue]

Go look for older 400 heads like from pre-'72 and you
will find 10:1ish compression, high 9:1s at least. But
probably need to install hardened seats on older heads.
Don't know about flow.

Look at a BOP-pattern 200-4R as an alternative to
the 700 series, simple and strong and a length match
to a TH350. You don't need the dual pattern bell.
Can find TV cable adaptors for most carbs.

[1fastcamarosss11]

if you go with the 7004r let me know soon i have an 2,400 stall brand new in box on ebay right now. will end early for 285.00 shipped. it is an b&m . one of the better stall. street friend with a little punch. pm me thanks jeremy

[jerry caesar]

http://216.178.81.108/forums/archive/index.php?t-423290.html

some info on the 200-4r swap

[snaggeltooth]

Go look for older 400 heads like from pre-'72 and you
will find 10:1ish compression, high 9:1s at least. But
probably need to install hardened seats on older heads.
Don't know about flow.

Look at a BOP-pattern 200-4R as an alternative to
the 700 series, simple and strong and a length match
to a TH350. You don't need the dual pattern bell.
Can find TV cable adaptors for most carbs.

I would agree on the heads except for one thing. He already has a set of 6X and he will have to do a port and valve job on them..Otherwise he will have to find a good set of older heads and do the same thing......
To find out your information all you have to do is pick up a current issue of High Performance Pontiac, there is always somebody asking the same question that you are and them guys know alot more about these things than we do .....

[blackout5.3]

hey thanks guys, you are a heap of help! if i had asked that sort of question at MM they would have had some sort of snotty answers and then turned that post into a how great my car is contest.

[toecutter_tx]

It might be easier and cheaper to find an Olds 455 and build from there.
It will bolt right in.
If indeed it is a 403 I wouldnt invest in any mods past an intake carb and headers.

[05gtoautoX]

the 403s had a big problem with oiling, cam/valvetrain and they were cast with very thin cylinder bores, also as some of you know I'm very biased toward pontiac engines, they are torque monsters and are very well built, if you have a 403, swap in a poncho 400, it too will bolt right in with the exception of motor mounts, look for some 1968/69 #62,48, 16 heads, a good cam/RRs and a set of headers. now the other thing is you're looking at a 700R-4 well in stock for it'll handle about 300 ft. lbs. of torque. so you will need it built, als you can get an adapter to fit the B.O.P. bellhousing. but just remember a stock 400 with either of those heads had 440ft./lbs of torque not to mention with any other mods, if you do have a olds 403, and decide to swap in a 400 pontiac let me know and if you need to find one I'm sure I can find you one or you can buy one from me.

[BB540]

You still workin on this build up? 400 is an easy build up to get that kinda power. The factory basically did all the work for you.
Its not that 6x are the best heads its that they are the easiest to find when your out junkin. Basically a simple cleanup on the bowls and port openings will help you out, as far as the rest go with about a 9.5 to 1 ratio with what ever cc head you use and then pick a cam

Any dual pattern cam with about a 112 lobe center would work good. You dont want to go past 110 on the pontiac motors on the street. Probally comp cams XE274H would work good for a street package. I know of another cam but I cant find the specs as it was a project I was building a few years back.

HYDRAULIC-High performance street, very Hyd. Hyd. 1800 to 6000
51-224-4 XE274H 274 286 230 236@.050 .488 .491 at 110°

I was gonna use the same basic package block and head package but with a chet herbert cam, a single plane intake, and an offset ground factoy crank for 6.8 chevy rods to make about 500+ horse. Rollor Rockers and good qualty locks are a must on pontiacs ! Same with using a windage tray!

Oh and I know some one is gonna ask about that crank set up. Basically it optimises your rod to stroke ratio and after market bbc rods are usually cheaper then pontiacs although in the past 5 years thats changed. Now eagle makes a crank thats already cut like that for bbc 6.8 rods for about $350 and with every one selling rods like the eagle h beam ones you can pick up a set for around 300-350! and as far as the pistons i think you can get trw's for that type of package but I know for sure ross has an of the shelf piston set up for that package. For what your doing you dont really need to do the offset stroker set up.

You should easily make about 400 horse with out doing that.

Pete McCarthy has a good book with a lot of basic info called "Pontiac Musclecar Performance 1955-1979" Other then that all I can say is hit up the true pontiac Guru's like Jim Butlers - www.jbp-pontiac.com, Rock and Roll Engineering - www.pontiacpower.com, sdperformance - www.sdperformance.com just to name a few.
The guys at SD were pretty friendly and knowledgeable back when I talked to them but that was a few years back.
Good luck

[Chirodan]

If I'm not mistaken, compression in a 71 firebird 400 was 8.2/1 so it is pretty low, but that is good for me. I'm trying to rebuild and forge for some kinda forced induction setup. Still looking into it @ this point.

Good luck... and nice car.:yup:

[blackout5.3]

i stoped working on that buildup, it was magnafluxed and found to have spider cracks all over the mains.. so im looking for a late 60s poncho OR go with that 383 stroker..

[1fastcamarosss11]

i have a complete 350 with everything brand new. let me know if interested, the block is out of an 70's truck.

all parts still in original summit boxes with receipts. :yup:

[blackout5.3]

well the guy thats doin it for me, can get a 383 stroked and lower end complete cheap, all i have to do is add heads, cam, intake, and they will still back it up with a 2 year warranty

[1fastcamarosss11]

let me know what you need i have it all new in boxes. :yup:

[blackout5.3]

:flex: saweeeet! cheap i hope LOL

[05gtoautoX]

check out ebay, they have quire a few poncho motors on there, if possible stick a 428 or 455 in there, If you like torque, if NOT then go with a SBC 383:)

[05gtoautoX]

OH BTW, a 428-455 have the exact same dimensions as a 400, and will bolt right in.

[Glenn]

Step one: remove smog cam

Step two: see how far you can throw it

Step three: replace with any decent cam, Crane has a nice RA replica.