I'm put crane 1.6 roller rockers on with a stud conversion kit and a cam
motions 500 lift cam in. My friend has the same setup in his r/t and he's
taking it to 6000-6200, is that a safe area?
----- Original Message -----
From: Holloway,Frank T <Frank.T.Holloway@KP.ORG>
To: <dakota-truck@buffnet.net>
Sent: Saturday, November 06, 1999 9:37 PM
Subject: DML: RE: RE: 318 Hop Up, Heads VS NOS
> Bill,
>
> I wish I had a book on mods for these. The flow numbers come directly from
> the heads we are putting on the engine we are building up. Maximum RPM, I
> would think that 5,500 would be about tops for a stock motor. The weak
links
> are the weight of the valve train assembly (primarily the lifters), the
> lifter bores and the factory rocker hold down assembly. The factory hold
> down bolts are 5/16-18. On my heads, we switched to SB Chevy studs,
7/16-14
> on the bottom and 3/8 on the top. This strengthens the top end of the
valve
> train. Stiffer springs will control valve float. The lifters, all HP cams
> have a smaller base circle so the lifter rides lower in the lifter bores.
> This will hopefully stabilize the lifters, there is not much we can do
about
> the weight. As far as valve train components, I am actually partial to
> Crane. The cam that I am running is a Crane. Because of the lift I want to
> run, I needed a 1.7/1 rocker. The only company that I know of that has the
> 1.7's is Crower. Select pieces that give you what you need. The only
company
> that makes guide plates (last time I checked) was Crower, so that is what
I
> am using. Again, pick the pieces that accomplish your goals. I am hoping
> that the combination that we have selected would be stable up to 6,000. I
> could probably raise it a little with stiffer springs, but the cam won't
go
> much past 6,000, torque peak will be around 4,200. On your engine, at
> minimum, switch to a stronger rocker hold down bolt. A rocker stud would
be
> better yet. The roller rockers are more stable and they do provide for les
s
> wear on the valve tips and guides. If you don't need any additional lift,
> then any roller rocker would be better than the factory rocker. Make sure
> they have been successfully used on the Magnum. Hopefully they will
utilize
> a rocker arm stud. Ideally, the studs should have the jam hex as part of
the
> stud. This actually stabilizes the stud. I hope this info helps...........
>
> > -----Original Message-----
> > From: WillTier@aol.com [SMTP:WillTier@aol.com]
> > Sent: Saturday, November 06, 1999 5:45 AM
> > To: dakota-truck@buffnet.net
> > Subject: DML: RE: 318 Hop Up, Heads VS NOS
> >
> > In a message dated 11/4/99 12:17:56 PM Eastern Standard Time,
> > Frank.T.Holloway@KP.ORG writes:
> >
> > << The factory heads do flow well for a production truck engine. Stock
> > form,
> > the intakes flow approx. 210 CFM @ .500 lift, exhaust flows approx. 133
> > CFM
> > from .400 to .600. Porting and larger valves on the intake can push the
> > flow
> > up to 270 CFM @ .500. Lifts much greater than .550 cause a decrease in
> > flow
> > and actually decreased to 250 CFM. The exhausts continue to increase
in
> > flow, even with lifts up to .650 inch. At .550 exhaust lift, flow is
> > approx.
> > 175 CFM. Because of the difference between intake and exhaust, split
> > duration cams are necessary (greater duration on the exhaust).
> >
> > Frank >>
> >
> > Frank
> >
> > You got to have a secret cheat book there don't you ? :-) Your
knowledge
> > of
> > these engines amazes me and I appreciate you sharing it with us. As I
skip
> >
> > through the posts deleting those of little interest I always check the
> > author
> > and read all of yours. I am a more knowledgable person because of that
:-)
> >
> > Thanks for your contributions..
> >
> > I do have a couple of questions though. How high can we reliably rev
> > these
> > engines, for drag racing purposes ? I have read that over 5500 is
trouble
> > but
> > with the new mods I have done the power band seems to have risen and the
> > thing is still pulling good and I seem to be getting the most gains in
> > performance by running it close to 6000. I believe the MP comp, in 93
> > atleast, has the rev limiter set to 6500 ? The second question is to do
> > with
> > the roller rocker deal again. Still have the stock rockers and have been
> > looking at going with the rollers. I know you are a crower fan but I
have
> > read good about others and recently about Wolverines. They had a couple
of
> >
> > things (according to the article in sport truck) like a set screw to
keep
> > the
> > studs from loosening, precise ratios and the showed where they could be
> > used
> > with the stock valve covers by drilling holes in the splash shield ? I
> > don't
> > know cost diferences but the crowers seemed rather steep ?
> >
> > Your thoughts on these ?
> >
> > Thanks again for your input..
> >
> > Bill
>
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