Topic: cam for a pontiac 400 with a 3.23 rear end

[pat]

i was looking for a good cam for a pontiac 400 (ys coded) with number 13 (about 72cc) heads and a 3.23 (px coded) rear end also i have headers a torker intake i havent decited on a carb yet i have a holey, an edlebrok, and a qudrajet to chose from. it has a stock block, pistons, crank.

[pat]

also the car has a 4 speed transmission. borg warner i dont know much else about it

tires that are on it are 245/60/15

[pat]

i read ricks series on cams and and now also need to know about rockers too.

i was going to use a stock type valve and spring.

and are there any short comings to the above set up?

[TAKID455]

try a comp cams equivalent to XE 274 or XE 268. the 274 will be better for the stick, but will prefer 9.5:1 static compression. HO racing's HC-02 cam would work nicely too. they are still available. I would installed 995 (?) comp cam valve springs as the lift will be towards the outer limit of the stockers. for the price, its also good insurance. a dropped valve will cost you the engine. I run full roller rockers to reduce wear.

[ronj1977]

i run a stock bottom end 76 block with headers,and 74 cc heads (62)  saginaw 4-speed w 3.23 rear gears  and the summit 2801 cam it is a tourqe monster i have been thinking about going up a size to the 2802  to lessen the tourqe a bit because as of now it gets squirrely in the first 3 gears so i kinda have to tether the throttle or the rear tires will let loose

[rkellerjr]

The XE274 and XE268 are going to be a bit much for the stock drive train, I wouldn't recommend them.  With my setup Pat I went with the Comp Cams XE262H which is a great cam with lots of RPM range, lots of torque, and easy on the stock drive train.  I love the cam.  If I could get traction out the rear end I'd "swear" I could lift the tires off the ground

When I did my rebuild I went mostly stock parts just a bit hefty llike forged rods, etc.  The engine was bored .040 but, I did add roller tip rockers to allow less stress in the valve train.

Anyway, hope that helps some.

[TAKID455]

The XE274 and XE268 are going to be a bit much for the stock drive train, I wouldn't recommend them. 

EH?? been running this combo for 3 years with no issues in front of a basic rebuilt driveline. the 274 is similar to the RA4 cam that was stock in the early cars.  highway speeds will put this cam right in the power curve which starts around 3k. This cam bleeds off some of the down low torque and moves it to the mid range so you can get off the line and not roast your tires. Although, if desired, that can be achieved.

[TAKID455]

Thanks Mike

Woohoo!!!!. 100%. sweet

In no way was I intending to belittle Rkellerjr in anyway. Just wanted to provide first hand experience of a proven example of a combination. Each person has an opinion and should be proud of them as that what makes this place interesting. If everyone had the same opinion, the world would be a boring place.

The 74 should have some tweaking by Dayton for better performance. If time allows, I'll let you tell me if there is a difference.

[rkellerjr]

Larry,

My recommendation comes from a couple Pontiac engine builders who do it as a profession.  Has your engine been rebuilt?  Are you using the stock valve (sorry didn't mean to say drive, I meant valve) train?  Those two CAM's would be hard on the stock VALVE train

[TAKID455]

My engine is rebuilt. I do all my own rebuilds. As far as 'stock' valve train as is original from day 1, no. I feel it is foolish to spend the time and money and not replace the valves and springs. Most valves will be pitted and or the seats may be recessed due to wear and tear. the original springs don't last long with lifts over .500" therefore I install comp 995 springs which have higher spring rates and can take the longer lifts. 400 and especially 455 ci is a lot of volume to fill using streetable small duration cams. To increase the area under the curve (duration and rate the valve is open), larger lifts are beneficial. Stock valve may be reused, but check to see if they have sufficient installed height to support the cam. A typical rebuild starts around 3500 on the cheap end, so why skimp out on 400 for new valves and springs?

back to the original poster how mentioned 'stock type' valve train, which does not indicate the original 197x parts will be retain. This is where the misinterpretation occurred between Rich & I whereas Rich assumed original 197x parts and I assumed aftermarket stock type replacement parts. This being the case, both parties are correct in their thoughts. I agree that the cams that I mentioned will be a little tough on original 197x parts, but not aftermarket stock type parts.

Hope the information provided allows pat to make a good decision.

[rkellerjr]

[ScottD3]

I have the 268 in my car with auto and it does well sounds good also.

[pat]

i think i am going with the 274 cam.
will the heads need any work done to put the 995 springs in? as the springs may or may not be oringnal to the heads i do not know as they were on there when i got it. i do not want to drop a valve and ruin my engine.

thank you all for your input this is a topic i have a hard time under standing.

[rkellerjr]

I'd recommend calling Jim LeHart at Central Virginia Machine Service and talking with him about this.  He's a veteran pontiac engine builder and well respected within the industry before you make any purchases.  Best wishes on your build Pat.

[Rarebird]

I used the Melling MTP-1 cam in mine and Im very pleased, great idle and monster amount of torque at low rpm , highly streetable,and no head modifications. and as for MPG I averaged about 16. IF I can keep my foot out of it.

 http://www.summitracing.com/parts/MEL-CL-MTP-1/