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This year
http://motorsportsvillage.com/forum/viewtopic.php?f=5&t=9791
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Author:  rick360 [ Sun Dec 23, 2012 4:36 pm ]
Post subject:  Re: This year

Beretta wrote:
At 800 lift and running 8000rpm IMO 250 on the seat is not enough....I have had issues there before and now running just over 300 on the seat and 825 on the seat and everything looks just fine and valve adjustment never moves...

With a BBC valve that weighs ~20% more than a sbc valve and larger diameter springs and retainers, it will need a lot more spring than a sbc.

I ran some used Nextec springs on my 18ยบ engine that had ~275# with .780" lift shifting at 9000rpm and never had a problem (titanium valves though). The 414 dragster engine had ss valves and 230# springs, .700"lift, turning 7200 at the shift. IMO a lot of people have gone to "too much spring is just right" valvetrains. A lot depends on the lobe you use. The slam the valve open lobes like a Comp TK lobe will need a lot more spring than a Comp Hi-Tech lobe.

The 383 engine I build and work on for a friend has a Herbert cam with net lift around .650" (shift ~7200-7400) and we thought his springs might be getting weak so we pulled them and tested them at 160# ... O:) I thought wow, not good. Put some 230# springs on it and back to the track with no noticeable change. [-(

I like the springs available today where they get weak long before they break normally, unlike the older K1000 types that would just break when they got bad. not good.

Rick

Author:  jmech [ Mon Dec 24, 2012 4:56 pm ]
Post subject:  Re: This year

I was looking for ideas building headers and i found this pic. Last one on the page. The best use for a nextec spring =;
http://www.yellowbullet.com/forum/showt ... p?t=434080

Author:  Elkyman [ Thu Jan 31, 2013 8:53 pm ]
Post subject:  Re: This year

PSI springs all the way for me... PAC and Nexteck can take a hike, but that's just my opinion... Get the biggest pushrods you can stuff in it, and your going to have reversion with that cam too:ie black carbon all the way up into your plenum of the intake!!!! been there already and just changed MY cam to help it out a bit. Running thru the pits at idle or low speed will do this too.
A 112 or 114 LSA would give you better power as a few cam grinders would say :-k seems like a lot of guys have a cam LSA like that, some more, some less.

Good luck with the tunnel ram, that should really be a fun ride \:D/

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