[PontiacDanny]

Hello Guys !

Can any one advice me with a cam selection. I am thinking of getting my 400 pontiac rebuilt. I will be using all GM Parts but I am thinking of upgrading my cam. I am looking for more power ofcourse and would love some rumpity rump sound while i am at a stop light... my 400 is the 220HP with TH400 Auto Trans. I am looking for a good start up power and hp increase of about 300 more or less... i am on dual exhaust with no headers.... I hate headers...coz they are always leaky... any advice would be helpful. Thanks

[PontiacDanny]

Hello Guys !

Can any one advice me with a cam selection. I am thinking of getting my 400 pontiac rebuilt. I will be using all GM Parts but I am thinking of upgrading my cam. I am looking for more power ofcourse and would love some rumpity rump sound while i am at a stop light... my 400 is the 220HP with TH400 Auto Trans. I am looking for a good start up power and hp increase of about 300 more or less... i am on dual exhaust with no headers.... I hate headers...coz they are always leaky... any advice would be helpful. Thanks

[Skip Fix]

Stock heads? block decked?

[PontiacDanny]

Hi there, yes stock 6X heads and yes the block is decked

[Skip Fix]

Double check they are the 6X-4 heads, should be on the 220 hp motor. Milled heads or pocket porting? The original 6X-4s had around 93cc milling gets down to 89. Compressin ratio can make a difference in cam selection and where to install cam.

The original cam is close to the 067 cam but retarded for what ever reason Pontiac engineers did for emissions. That 067 installed straight up would wake it up a little as it traps more compression.

I just built a "driver" 400 for my son's 81 that is a 0.030 400 with milled 6X-4s decked block that is using the Summit 2801. Slight lope at 750-800 idle. Ran high 14s at the PSN but needs some race tuning. The factory 068 cam in a 400 is usually a great cam, never put one in a lower compression motor. I would think a slight intake centerline advance would compensate for the lower compression.

[Thumpin455_GTO]

I'v run an Ultradyne 280-288 with stock unported heads. Worked really well, had alot of low end with a 455 and was a decent power cam in a 400. Keep it under 236 @ .050 and you should be okay, split duration and lift up to .500. Install 4 deg advanced if it isnt ground advanced.

Or you can get a smaller cam with a tight lobe separation and get the lope wihtout the penalty of vacuum and low end torque that a bigger cam provides.

[prostreetpower]

hmm..im trying to decide a cam for my 77 6.6 200hp 4-speed engine, would u guys say the same thing? Was thinking of getting the comp cams k kit on sale at classical industries for $409. It comes with a Xtreme energy cam with .477 intake .480 exhaust, 268 degree intake duration, 280 degree exhaust duration, lifters, chain set, valve springs, valve spring retainers, valve locks, valve stem seals, assembly lube, instructions and decals. Might just be something worth checking out Danny

[Thumpin455_GTO]

PSD with a set of ported heads that thing would really wake up. The XE cams are impressive for street pieces, been lookin to swap one into the GTO.