[crustysarge]

Italian buddy called me yesterday and want to swap his XE274 cam for a bigger solid cam. he has a 400 stroked to 455 with ported 6x-4 heads. Worth it to go solid and a little bigger?

[Steve C.]

"....a little bigger?"

As a general rule when going from a hyd flat tappet to a solid flat tappet many add a significant amount of additional duration. Not uncommon to read 8-10 additional degrees, while in many instances its touted more than that.

Example, note the combination here:
http://www.pontiacstreetperformance....uild45500.html

After this write up Lee improved on his time over what is stated here. I believe it was a best of 11.46 at 115.4 mph. And in our horrid Texas summer heat he ran 11.70 at 113.4 mph. Lee later changed to a Ultradyne solid flat tappet cam with 247/247 degrees at .050 with .575 lift on a 108 lobe separation. With the change he ran a best of 11.27 at 119.61 mph. And Lee reported no significant decrease in driveability with the change dispite the 16 degrees additional intake duration.




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[screamingchief]

Well,,,the Crower #60310 solid is ever so slightly "bigger" than the XE274 cam is...

Though if it were me,for a healthy solid cammed 455 cid combo,I'd go with the Crower #60311 solid cam @ the minimum.

The Crower #60310 solid is a much better cam for a strong 400 cid combo.

I personaly dont subscribe to that old add 8° to 10° of duration @ .050" POV,IMHO it's way too vague,and there's just too many things that it wont account for,me I prefer to look @ the actual valve events of both given cams to get an idea how they compare.

That's especially true when things like the LSA and installed centerlines are changed between the two given cams.

Ask me,more often than not,it's gonna take something like an additional 15° to 20° (@ .050") to make equal to -or- more power than a "comparable" hydraulic cam combo will make.

That is especially true with some specific solid lobes that have less seat timing.

FWIW

Bret P.

[crustysarge]

I'll ask him what cam he is looking at, I always refrain from giving any cam or type of oil advice anymore.

[Formula8]

My 60310 is plenty of cam for my 455. It is surprisingly "rev happy" and the engine has no problem turning up to 6200 RPM and pulls there but probably not worth going too much over 5800. I have a lot of gear and a pretty light reciprocating assy though. I agree with SC in that I bought this cam for a 400 but played with it on desktop dyno and figured it would work just as well for a 455 and it does. I never have ran a comp cam so I have nothing to compare it to but my 60310 does everything I need it to do in my car.

[Cliff R]

The best upgrade would be to move up to a small hydraulic roller cam. It will take around 14 degrees more duration at .050" from a solid cam to start showing improvements. A small hydraulic roller with about the same .050" duration will make more power at every rpm, and enjoy good idle and low speed manners as well.

We did some cam testing a few years, back, and LOST power replacing a Crower 60919 cam (231/240/113) with a 240/248/112 flat solid. Despite the increased .050" duration, modern lobe profiles and quite a bit more lift, it made LESS power at every rpm.

I replaced the solid on the dyno with a 230/242/112 HR cam, and made 30 more HP and nearly 50 more ft lbs torque.

A couple of years ago, we installed a custom flat solid cam in a 455 and dyno'd it, it spec's out around 246/254/110. We were only hired to assemble and dyno the engine. If use SD Performance 290cfm KRE aluminum heads, with a port matched RPM intake. On it's best pull it made 524hp and 540tq. We typically see over 550hp and 600ft lbs from that same set-up using SD Performance's 236/245/112 HR camshaft.....Cliff

[Steve C.]

Stated- "I personaly dont subscribe to that old add 8° to 10° of duration @ .050" POV,IMHO it's way too vague,and there's just too many things that it wont account for,me I prefer to look @ the actual valve events of both given cams to get an idea how they compare."

Excellent point by Screamingchief. My mention of 8 to 10 degrees was as typical by me just information regurgitated that I've read before on the subject, and not necessarily a recommendation. And it's interesting to note the Crower 60311 solid cam SC mentioned has the same 247 degrees intake duration as Lee used in my example above. But note the Crower has a wider lobe separation.

Again not a recomendation but a another tid bit that might be of interest. Thirteen years ago in Pontiac Enthusiast magazine they had an article that included a stout street/strip combination for its time. Touted as something that might be driven fewer than 3,000 miles a year for cruising, occasionally driven to the strip. The recommendation was for a solid flat tappet cam with 255 degrees intake duration.




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[disc0monkey]

Originally Posted by Cliff R

Despite the increased .050" duration, modern lobe profiles and quite a bit more lift, it made LESS power at every rpm.

Cliff would you conclude that modern lobes just aren't that benefitial with flat tapped compared to Hyd roller

[rad400]

O.k. just wandering would the Crower 60310 .240/.248 112 @50 show any more power over my crower 60210 .229/239 @.50 108 in a 406 #12 heads unported TII 750 vac secondary 3500 stall 3:73 rear in a 79 T/A

[ITSBACK]

Italian buddy, lol.

[screamingchief]

Originally Posted by rad400

O.k. just wandering would the Crower 60310 .240/.248 112 @50 show any more power over my crower 60210 .229/239 @.50 108 in a 406 #12 heads unported TII 750 vac secondary 3500 stall 3:73 rear in a 79 T/A

IMO,yes the #60310 solid cam should make slightly more power than the #60210 hydraulic cam makes.

But it wont be a whole bunch more power,they are both pretty comparable cams overall,this despite some obvious differences in the advertised numbers.

The solid cam will almost certainly shift the power band upwards ever-so-slightly,that's pretty much a given.

But that'll be NBD with that stall and rear gearing.

And do note that it should also be somewhat less octane sensitive as well with the #60310 solid cam and those #12 heads on there.

Probably idle a tiny bit smoother too.

And just for good measure I'd probably wanna run the solid with some 1.65 ratio rockers if your not already running such.

FWIW

Bret P.

[Cliff R]

"Cliff would you conclude that modern lobes just aren't that benefitial with flat tapped compared to Hyd roller"

I hate to conclude anything from a single test. As for cam testing, dyno, track, etc, we see very little of it. Just too time consuming, and too costly. If you carry over more than one day, or have to pull the engine off the dyno, then back on like we did, it can get very costly.

In any case, and IMHO, the "modern" fast ramp flat cams just don't make big power increases over older stuff. You really have to choose them carefully, as you can take out quite a bit of seat timing looking specifically at .050" numbers, which has become the industry standard for posting cam specs......Cliff

[Skip Fix]

I know some folks that have good luck with Ultradyne 288/296 solid flat tappet and I bet tehy would be considered "modern lobes"

[crustysarge]

Crower #60311 is what he is looking at.

[screamingchief]

Good solid cam for a hot 455 cid combo,I'd tell him that's an excellent choice.

And be sure to use the Crower #66962X980-16 "coolface" solid lifters too.

Also,be sure to check that the valve springs & valve set-up are up to the job as well.

Bret P.

[crustysarge]

But worth going from the XE274?

[screamingchief]

Originally Posted by crustysarge

But worth going from the XE274?

Is 30 or so extra HP (albeit at the expense of a slight loss of low end torque and a slight upwards shift of the power curve) going to be worth it to him?

http://forums.maxperformanceinc.com/...d.php?t=663869

Granted that's just how that one combo responded to that very same change.

But Ryan's results from that swap are pretty clear.

I dunno,you tell me if that's what that fella is after.

If he's after more than that,it's almost certainly gonna be a lot more complicated (and expensive) than a fairly straight-forward hydraulic to solid flat tappet cam change.

Me,for a healthy 455 cid combo,I'd take the Crower #60311 solid over the Comp XE274 hydraulic anyday.

FWIW

Bret P.