|Astangthang ||06-25-2018 08:46 AM |
Has anyone ever advanced their cam? If you did, did you notice any difference? I will tell you what I'm thinking about doing. I'm going to be building another 2v this winter to drop in next spring. I had plans to put my new pi heads, and my MHS stage 2 cams on this spring, but nothing has panne out. My heads should be done next week, but all the circle track guys have Randy, my engine builder slammed. So what I'm thinking of doing is just hold off on installing the pi heads this year, and use them for my other engine getting built over the winter, and $ is no object on that motor, it will be a 7k rpm, high compression, NA, forged. So hear is what I'm thinking, take my new cams which are 224/226 .550/.530 110/113 ICL 111.5 LSA and install them in my NPI heads w/ nextec manely springs and +60 retainers. Instead of installing them at the 110 centerline, I was going to advance them to 108 which the NPI likes. At the 108 centerline, this will have my exhaust at 111 which isn't bad at all. I was looking at MHS npi cam specs, and they have a cam that's pretty close to what I have, its 228/230.550/.525 106/112 ICL 109 LSA. There is differences between these cams by only a couple degrees. My long tubes, and the longer exhaust duration will help the exhaust port on the npi heads, so I'm not worried about the ex.port. I just had planned on getting the pi heads installed earlier this year, and it just didn't happen. I figured might as well wait till next year on the heads, save them for the other 2v next spring, and put my cams in the NPI heads, let them rip. Cost will be down this way, and plus my npi runs almost to damn good now, so I would honestly like to see what it will do. What do you guys think? Do you think I should go ahead and install the cams in the NPI heads with my pi intake, and save the pi's for the winter/spring engine? I don't take this car to the track or race it often. I dig the port velocity for the NPI, plus I think my cam is more tailored to the NPI head. The NPI in the car now has the block decked .010, the heads were .020, with a 3-angle valve job, cylinders were bored .020 over also. Those 4 specs is where I think the extra power is coming from. I've read that the npi valves were so bad from factory that a proper 3 angle was worth as much as 15hp. I definitely tell a big difference between this engine and my old engine, and my old one only had 70k on it. I love the underdog so I think that's why I like the NPI. Nick McKinney (RIP) did a test on a stock npi with a 222/225 .525/.500 108/114 ICL 111 LSA camshafts, w/ shortys headers, x-pipe, flowmaster C/B, PI intake, C&L plenum, 70mm T/B, through a 5-speed and laid down 273rwhp. This was a factory 9.3 CR also. I bet if he had long tubes it would have yielded another 5-10 HP no problem. If I advance my can by 2°,my cam specs will be exactly almost these, so I have good promise for my NPI. I'm going to run a pi lash adjustors on the intake valve, and keep the NPI ones in there for the exhaust. I took the can cover off and noticed the NPI has a bigger blead orifice than the PI. This will help the events also. What you guys think?