[ponyakr]

"... is there no place for it in any Pontiac engine?..."


I've read that those cams were made to increase cylinder pressure in low compression engines. There were plenty of low comp(7.6-8.5:1) 350 and 400 Pontiac engines in the 70's. So, for those just wanting to increase performance a bit, without switching to high comp heads, these steep ramps are supposed to fill the bill.

But, since you don't want the noise of Rhoads lifters, you may wanna go with a Lunati Voodoo 262, instead of that XE 262. I've read that the XE cams make noise, because of slapping the valves shut. I've even read of several guys who pulled their XE for this very reason.

And for the 455 cam question, if you can't stand the Rhoads, but want lots of idle vac, you'll just have to settle for less cam, or go with a high dollar roller set-up. But, since I said that, I'm sure somebody will come up with some cam that is bigger than the 041 and has more vac, without Rhoads. That seems to be the way this thread has gone. What don't work for some, seems to work great for others. So, I reckin it all depends on who you believe. Or you'll just have to try 'em in your engine and see how they do.

But, then I'm no expert. Some of them will be along shortly.

[nytrainer]

Thanks Ponyacker. I have the XE262 and regular lifters. Both like new and lifters matched to the lobes when removed. Just looking for a place to use it. Thinking it might be a better performer than the orig. cam (pn 254?). '68 350 rated at 9.2:1 cr but reality probably 8.5:1 I'm guessing.
I had the springs setup for the 041 (ported, 10 degree locks, new guides, clean up mill, cut for Viton? seals, pushrod holes enlarged, new valves, etc) to use on the 455 block but after reading the thread it's as clear as mud as to what hyd. cam I should use. I think roller setup would need different springs too so I'd like to keep the heads as prepped. Just need to have the gurus direct me to which cam.

[Steve C.]

Running a big cam and getting less than adequate vacuum for your power brakes?

Solve those problems with a electric vacuum pump kit. Easy to hide if desired.

One of many companies: http://www.mpbrakes.com/accessories/vacuum-pump-kits


.

[neill]

Originally Posted by nytrainer

Thanks Ponyacker. I have the XE262 and regular lifters. Both like new and lifters matched to the lobes when removed. Just looking for a place to use it. Thinking it might be a better performer than the orig. cam (pn 254?). '68 350 rated at 9.2:1 cr but reality probably 8.5:1 I'm guessing.
I had the springs setup for the 041 (ported, 10 degree locks, new guides, clean up mill, cut for Viton? seals, pushrod holes enlarged, new valves, etc) to use on the 455 block but after reading the thread it's as clear as mud as to what hyd. cam I should use. I think roller setup would need different springs too so I'd like to keep the heads as prepped. Just need to have the gurus direct me to which cam.

I believe the stock cam for that motor had either 269 degrees or 273 degrees duration. my 455 with 275 duration often pings with 91 octane and 8.96 to 1 compression. I would be very hesitant to try it in the 350. But I am no expert

[Nicks67GTO]

I just saw a dyno video on facebook from a very well known Pontiac builder. 4.25" stroke 400 with aluminum D ports, RPM and FAST 2.0 EFI. I asked for details but he didnt disclose. It made 488hp@5000 RPM and 580 lb/ft @ 3900. Not bad but not overly impressive imo. I was curious about the cam selection and port work as it seems compared to others with similar combos like the KRE290/RPM/OF combo, that this one its leaving a lot of HP and probably 5-700 RPM on the table for minimal costs. Ive also seen people mention that these guys like to run the modern lobe, tighter lsa profiles, I guess thats why its maybe worth mentioning here.