Pontiac 400 Cam Suggestions?

I need some cam grind advice for my motor in the '40 Plymouth g***er, here's what I'm working with...'76 Pontiac 400, 6X heads, Weiand 4bbl intake, Holley 4150 600cfm carb, fenderwell headers, stock points ignition, stock fuel pump and compression, stock TH350 trans and converter, 3.23 rear gears in a stripped down '40 Plymouth 2dr sedan...I want more low end and mid range power instead of high end...so what cam would you guys recommend?

 

Now before everyone gives me **** for not having an all-out insane drag car setup, know this...the parts I have right now are ALL I have, and as such I must work with them...certain things will be upgraded later like the heads/compression, trans/converter and gears...I'm keeping this car mild for now...

 

The key to performance is cylinder pressure. If you have stock compression and stock gears and stock converter I would stay below 224@.050 duration. My favorite cam for your combination is a COMP CAMS 270H Magnum. It is not so big as to bleed off compression and lose low speed torque. It has a nice sound at idle and works with a stock converter. It will pull hard up to 6000 RPM. You will LIKE the way it DRIVES!

 

Is this going to be a steet car or race car ?

 

I'd suggest something like a blueprint RAMAIR IV cam 308/320 465 lift
Pontiacs like a lot of duration {I have a 347 Pontiac Injected frt engine dragster}
Jerry

 

is this a street car? sounds like it with stock convertor and 3:23s. posi? the ram air 4 cam is too much for a 400 and this combo even if you use rhoades lifters. for pure driveability and you did mention low and midrange improvement i love the good old h/o cam commonly referred to as the 068 cam. originally used on the tri power cars. I-212/E-225 duration @ .050 .406 lift. most guys add 1.65 rockers which add a couple degrees duration and bring lift to .447. this is a very streetable cam with a noticable lope. install it straight up. i ran 12:35 in my 68 gto with this cam tho its 455 powered w/3:55 rear. and the car got driven everywhere. good luck..lets see some pics

 

unless yoiu have future plans for power upgrades like a tunnel ram, a comp cams 268 will be slightly more streetable than the 270 depending ony our compression ratio. the 6x heads are an excellent start. if you use ahigher lift cam, invest in 7/16 rocker arm studs to replace the stepped 3.8 studs. and use poly locks instead of the single use stock nuts Pontiacs work better with dual pattern cams. avoid single pattern cams that copy chevy lift/ duration curves

 

How far away from the heads/driveline changes are you?
If it's a short time, cam the motor for the new parts and deal with a rough idle and low vacuum for a little while. It will make you more prone to finish 'er off. That's my thinking anyway. Kinda hillbilly, but it's not like the thing won't go down the road with the wrong cam.

 

It'll be a street car for the most part now, and the 3.23 rearend is a posi...the upgrades will be few and far between due to money and moving problems this year...and the heads are junk 2bbl '76 heads, maybe they're 4X...I can't remember...my first upgrades will be a torque converter and shift kit...

 

what he said! i had that same camshaft in my 67' firebird 400/4spd/4:11's and it pulled like a john deere tractor. only good for manual trans or high stall auto.

 

If it's only for high stall/manual trans and 4.11 gears, then why recommend it for me? I looked at the 270 Magnum from Comp Cams, I love the looks of it...are there any other companies with a comparable grind I should look at? Crane, Lunati,etc...

 

give nielson cams a call...he can grind you one for MUCH less than an off the shelf one and it'll be setup to your combo. he's gonna do the one for my caddy 346 and probably one for my 461 olds. quoted me $140 for the olds cam. 801-451-7745

 

Ruiner,

The problem you have there is a lack of compression. The '76 400 with stock 6X heads only has a 7.6:1 compression ratio. You can cam that engine all the live-long day but without some compression, you're not going to gain much performance.

You would be far better served finding a set of earlier heads to get the squeeze up and go from there. And don't fall into the trap of trying to find the more popular performance heads like 670s or what have you. Even a set of standard heads off of a 1970 350 2-barrel engine would give your compression ratio a swift kick in the pants. No, they won't flow like hot racing heads, but for an otherwise stock engine, your bang for the buck will be way up there. You can still find these kinds of "standard performance" heads in junkyards and at swap meets all over the place.

All you need to do is get the squeeze up into the 9:1 range to see a big change in your engine's performance over the stock 7.6:1.

 

Does that come with lifters? I'll give him a shout when it comes time to get my cam...there's a seller on evilbay selling the Comp Cams 270H Magnum for $150...I like the idea of supporting a small-time guy if his quality is good...

 

shpotty, thanks a ton, I'll start searching...and that ebay seller has the Crane 272 Energizer for $165 shipped, and the Comp Cams 270 Magnum for $195 shipped...maybe Nielsen would be a better deal...

 

PM member VOETOM. His Dad is Jim Hand who wrote the Pontiac performance book.

 

Ok, I found a pair of 350 heads locally cheap that are #17 heads, who knows what c/r those heads are? And VOETOM will be contacted later when I start getting away from stock parts and get into making real power...

 

I looked up the 17 code heads, '68 350 265hp 9.2 compression ratio, looks like I found what I needed...sweet...now maybe that cam swap will do something...

 

Have fun....tons of info on here...says #17 heads are 1968 350 heads with 8.6 compression ratio 1.96/1.66 small valve heads...a step in the right direction.

http://www.wallaceracing.com/head1.htm

 

I called the guy with the heads, and even though I can get them for $50 they have been sitting outside in WI for over a month in the snow...

 

The last time I put a cam in a Pontiac I got it from Jim Butler.
http://www.jbp-pontiac.com/
His recommendation was spot on...

and I'm waiting for flamedabone to chime in...

 

Yea...I'm here. All the above guys pretty much have it covered. Pick teh cam for teh application and the rest of teh combination.

Also, swap for a set of heads in the 96-100 cc range. (6X -4 and 6X -8. Also lots of 4Xs have the right cc.) Check out performanceyears.com for a complete list of cyl head casting #s and chamber ccs.

Good luck and holler if you need anything.

-Abone.

PS. I didn't know VOETOM is Jims young'n. Jim is the Tony Hawk of the Pontiac world. He literally wrote teh book...

PPS. Show us some PICS!!! of this beast.

 

With 3.23s and a turbo 350 the suggestions for an 068 cam and heads with smaller combustion chambers are spot on, although you might get away with a Ram IV cam and Rhoads lifters if the car is light enough. Just lose the carb and intake, the factory manifold (aluminum or iron) with a Pontiac or Buick Q-jet (around 800 cfm) will make more power and be more streetable, (although I won more than my fair share of street races with a P4B Edelbrock and a 3310-1 Holley it's not reputed to be the hot setup).

In your search for heads, I'd hold out for ones with the biggest valves you can find (2.11, 1.76 I believe), and don't go too small on chamber size or you'll lose all your power backing off the timing to control detonation. They're out there, you just got to look around. Add a free flowing exhaust and you're good to go.

Lots and lots of good info out there, internet ( start with forums.performanceyears.com) and print, with the Jim Hand book being a good place to start (and currently in print). The H O Specialties books from the early 70s had a lot of info too, but are really hard to find. Don't forget the factory manuals, either.

 

I have 6X-8 heads on it right now, the stock '76 400 2bbl heads...might I ask why you're suggesting to put 96-100cc heads on it? That seems relatively low compression-wise...I have a friend that might get his hands on some '71 350 heads via his friend that has a bunch of pontiac motors laying about, they're 8.0/8.2 compression...not great, but better than what's on there...he also mentioned I could just have my 6X-8 heads milled to bump up compression and that they flow quite a bit better than the '71 350 heads, so I might look into that option as well...

 

The '71 heads are 90cc with smaller valves than my '76 6X heads, and I found a chart on Wallace Racing that if I mill the heads around .045 I'll drop my 6x heads down 10cc's...maybe I'll just stick with the heads I have and have them milled, get a new cam and lifters...after milling the head, will I need new pushrods?

Here's the motor as it sat before being put into my '31 Plymouth project...


And here it is mounted in my '40 Plymouth g***er (the car that we're talking about in this thread)...

 

Ok, here's another question for you guys, and I know a lot of this is personal preference, but I'll ask anyway...what would you guys recommend for ME as far as cam style, roller, hydraulic or solid?...Now personally, I'm a wimp and would usually just go with a hydraulic cam and keep it closer to stock because I HATE ****tering parts out of motors by selecting the wrong parts, but the thought of hearing a solid lifter cam motor through open headers makes my boy parts tingle...I'm starting to lean towards having a custom grind solid lifter cam similar to the Comp Cams 270 Magnum...thoughts?

 

The 270 is still quite a bit for a low compression 400. The 068 would make more power across the rpm band, thus making a quicker car. Cams designed for more top really lose out on the bottom end- like the RaIV cam.
A Summit Racing 2801 is similar to the o68 but has some nice additional lift built in.
I would recommend getting Jim Hands book Max performance Pontiac v-8's than that would help you understand your engine better and picking the right cam, unlike putting a racing RAIV cam in a low compression 400, That would be a total dog. The 068 would run circles around it in that engine on the street, it really needs at least 3000 rpm to get that cam going plus some compression 10.1.

 

Hydraulic roller hands down....

 

RAM AIR 3 or 4 camshaft spec's, I ran a RAM Air 4 cam in my Bantam altered and it was great, I had a 400 with trw flat tops and 6x heads. Lots of low end and ran down the 1/4 mile real good with 3.52 gear and a turbo 350 trans, 2000 stall.

Jon

 

use the the ram air 4 cam it was used on the gto's for good power but not crazy.