455 or 400 needed.

What is the cheapest place to get a pontiac 400 or 455 for a 1973 firebird. thanks

I have a nice pontiac 400 with some aftermarket improvements that is ready to run, NY zip 12538, pickup only no shipping.

Can also ask here:

http://transamcountry.com/forum/

I am in CA.

Ok guys I got a creat 400. It is the ram air v8 with 366 hp. I plan on just doing a cam and valve springs. What cam would be best for the ram air heads? I don't want to over cam it. Thanks

Ok guys I got a creat 400. It is the ram air v8 with 366 hp. I plan on just doing a cam and valve springs. What cam would be best for the ram air heads? I don't want to over cam it. Thanks

What do you mean by "best" and "over cam"?

If you want the most power possible out of those heads you will most likely end up with a cam that is fairly unruly on the street.

What are your goals for the motor/car?

Ok what cam can I go with without absolutely having to run a larger stall.(Stock stall)

Ok what cam can I go with without absolutely having to run a larger stall.(Stock stall)

Autos are out of my range of knowledge. I'm sure someone else can help you with that.

I run a 224* flat tappet cam in my sbc 400 with a stock converter and that's about the limit IMO.

Ok thanks, what kinds of times do you think it will get? Because my uncle is trying to build it to beat me. But I don't think it will run a 12.1 with stock stall and the ram air 400 with a cam only.

I don't think so either. With stock stall, smog heads, 750 vacuum secondary Holley on a dual plane intake, 3.42s & Radial T/As, my best is a 13.7 @ 101. Track altitude = 4,100 ft, so figure ~ 13 flat at sea level. He'd need more stall, gears, cam, and a sticky tire to run low 12s.

I too am considering building a 400 from a 1971 impala what can I do and why do many people refer to this engine as weak kneed? I want to obtain atleast 450 rwhp from a streetable application with 3.73 gears, long tube headers, and whatever bolt on aftrmakets parts I need. I need guidence. Also I here of people stroking the moter to a 406 but a 350 gets stoked to a 383 I dont understand why a 400-406 would make a good amount of power.

I too am considering building a 400 from a 1971 impala what can I do and why do many people refer to this engine as weak kneed? I want to obtain atleast 450 rwhp from a streetable application with 3.73 gears, long tube headers, and whatever bolt on aftrmakets parts I need. I need guidence. Also I here of people stroking the moter to a 406 but a 350 gets stoked to a 383 I dont understand why a 400-406 would make a good amount of power.

Alright, let's start with the 400 sbc's bad rep. A lot of people used this block (and still do) for racing because of its large bore (4.125") and capacity for large stroke. It's not a particularly strong block when you start boring the cylinders and running a lot of boost or nitrous, or even just high RPM horsepower. It's also not as weak as some people make it out to be, you won't have a problem with your power goals. If i'm not mistaken the earlier 400 blocks (like yours) are stronger though.

Second, a 400 block does not get "stroked" to a 406, it gets "bored" .030" over its stock 4.125" bore. That is just a common practice to clean up the cylinder walls and perhaps unshroud the valves. A 350 is turned into a 383 swapping in the crank from a 400, which has a longer 3.75" stroke (hence the term "stroker motor"). If you want to do something similar to your 400 then give it a 4.0" stroke with the .030" overbore and you have a 434, without the .030" overbore it is the famous chevy 427.

Third, if you want to make good power out of your motor then don't look at the shortblock, look at the heads. Buy yourself a good set of heads and then build the shortblock into something that the airflow of your new heads can support. Get a good intake and cam to match your goals and voila! you have yourself a bad nasty, streetable, 450rwhp.

Just my humble opinion, I'm sure some of the other guys on here can help you further.

Alright, let's start with the 400 sbc's bad rep. A lot of people used this block (and still do) for racing because of its large bore (4.125") and capacity for large stroke. It's not a particularly strong block when you start boring the cylinders and running a lot of boost or nitrous, or even just high RPM horsepower. It's also not as weak as some people make it out to be, you won't have a problem with your power goals. If i'm not mistaken the earlier 400 blocks (like yours) are stronger though.

Second, a 400 block does not get "stroked" to a 406, it gets "bored" .030" over its stock 4.125" bore. That is just a common practice to clean up the cylinder walls and perhaps unshroud the valves. A 350 is turned into a 383 swapping in the crank from a 400, which has a longer 3.75" stroke (hence the term "stroker motor"). If you want to do something similar to your 400 then give it a 4.0" stroke with the .030" overbore and you have a 434, without the .030" overbore it is the famous chevy 427.

Third, if you want to make good power out of your motor then don't look at the shortblock, look at the heads. Buy yourself a good set of heads and then build the shortblock into something that the airflow of your new heads can support. Get a good intake and cam to match your goals and voila! you have yourself a bad nasty, streetable, 450rwhp.

Just my humble opinion, I'm sure some of the other guys on here can help you further.

Thats some good info Jay thanks do you recommend a head and cam set? Also when you say build the short block are you talking about pistons cranks and rods or what? Its ok to laugh I am very new to all of this but I want to learn so I will stumble around in the dark if I have to. But I digress. Is there a kit or something to that effect already put together or do I have to peice the components together myself. One more question if the 426 hemi put out 500hp does that mean the 427 could also?

Your 400 can make over 500hp with the right heads and cam.

Ok guys I got a creat 400. It is the ram air v8 with 366 hp. I plan on just doing a cam and valve springs. What cam would be best for the ram air heads? I don't want to over cam it. Thanks

Are you sure it has R/A Heads cause realisticaly all D port Pontiac Head's are the same, `68-70
If it is a 366 Horse R/A V8 then all that's different from a standard 350 HP 400 is the cam and the tune.
A Comp Cams Magnum 270H is a great performer and can be used with a stock stall.

Thats some good info Jay thanks do you recommend a head and cam set? Also when you say build the short block are you talking about pistons cranks and rods or what? Its ok to laugh I am very new to all of this but I want to learn so I will stumble around in the dark if I have to. But I digress. Is there a kit or something to that effect already put together or do I have to peice the components together myself. One more question if the 426 hemi put out 500hp does that mean the 427 could also?

I've always been partial to Dart heads, but there are a lot of good heads out there. I'm no head porter or cam designer, and I would be asking these guys the same kind of questions. The Dart Pro 1 CNC heads would be a great out of the box head for you I think. It's a 227cc runner which is probably a little smaller than optimal for a 427 but I think it would make for good street manners. Again I can't stress enough how little I really know compared to some of the other guys on this board. Give me a while and I can probably find a good cam to go with those heads, but if you called Comp Cams after you decide on everything else they can get you what you need.

Shortblock refers to the block with the rotating assembly (crank, rods, pistons). To some people that even covers the cam. Longblock refers to shortblock + heads (sometime without the valvetrain). You can buy a rotating assembly with 4" crank and 4.155" bore and rods the right length already balanced and ready to be installed.

A 427 is capable of well over 800 hp naturally aspirated with the right set of heads and everything else spot on. I think 500hp should be pretty easy.

Let me look around and see if I can find you a good deal on a rotating assembly and then a cam that would work well with those heads. You may very well be better off calling comp cams and asking them though, last time I talked to them they had some good knowledgeable help.

WOW this thread is confusing, I think some of you guys are talking about Chevy 400's and the others are talking about the Pontiac's....

WOW this thread is confusing, I think some of you guys are talking about Chevy 400's and the others are talking about the Pontiac's....

Yeah I was talking about Chevy 400s with giwanabe, seeing as how the motor is from his Impala I assumed it was an SBC.