[540STREET]

Ive been waiting a couple of weeks now for ud harolds response on a camshaft for my 540. Spring is here and im getting the burnout withdrawl syndrome, i end up beating my everyday vehicle to death. I wish somebody would do a test between a solid flat tappet and a hydraulic roller especially on a dragstrip with similar specs. I have seen way to many motors die with the solid roller issues on the street. My 540 has 10 to 1 with afr 305's victor junior and 950 quickfuel. i dont care about vacuum
or idle quality just some nice power. Im so sick of these 650 horse supercharged mustangs owning the street!!! anybody have and ideas?

 

[GRN69CHV]

Do a search on here for 555" builds. Jim did back to back dyno testing of solid flat, hyd roller and solid roller.

 

[540STREET]

thank you, im still learning how to move around this site. computers and me dont get along that why i still run a holley!

 

[GRN69CHV]

Jim's id is 540hotrod. Follow his posts, he definitely understands big inch street/strip motors.

 

[Calculated Risk]

Similar specs between a flat tappet and roller tappet cam? Why? Have you ever seen the two lobes next to eachother? Your not comparing apples to apples, about the only number that might be the same is advertised number. Even the hyd roller is opening the valve so much faster and holding it open longer. If you just think about how the lobe is designed you could see why a test wouldn't be needed.

 

[crazydavey]

you'd have to be Crazy to run a hyd roller...

welcome to the site!!!

contact Chris Straub...he will fix you up...

 

[The Old Reliable]

My 540 has 10 to 1 with afr 305's victor junior and 950 quickfuel.


Im so sick of these 650 horse supercharged mustangs
owning the street!!! anybody have and ideas?[



/QUOTE]

Just about any of the current-design camshafts from the Lunati VooDoo lineup in your 540 should spank those posers in the factory SC Moustaches.

 

[johnretired]

Similar specs between a flat tappet and roller tappet cam? Why? Have you ever seen the two lobes next to eachother? Your not comparing apples to apples, about the only number that might be the same is advertised number. Even the hyd roller is opening the valve so much faster and holding it open longer. If you just think about how the lobe is designed you could see why a test wouldn't be needed.

Sorry but you cannot compare cam lobs by looks!!
A flat tappet and a roller are very different concerning where they actually are contacting the lobe.
Yes a roller WILL accerate a lifter faster but you cannot compare by looking at the cam!!! Profiles on a chart--yes.

 

[540Hotrod]

You'll find that *good* flat tappets actually come off the seat pretty fast...often faster than rollers. As they progress is where the roller can shine and get a lot more lift for a given duration point.

In the engine they are discussing the 270* flat tappet was a lot closer on P/V clearance than the 268" solid roller with both on the same ICL and same LSA.

For example the flat tappet lifted .151"@TDC vs the solid roller at 147"@TDC. As it progressed past TDC it kept getting tighter on P/V.

Just goes to show you lift doesn't matter. The flat tappet was .696" lift while the solid roller was .788".

This wasn't a crazy flat tappet....but it was a good one from Crane. In fact all 3 cams were Cranes and did incredibly well. The solid roller was tested afterwards against some much more aggressive very serious bad boys and held its own for sure.

There was about 25-30HP difference between the two cams at the peak depending on carb/intake I had on it at the time. It made over 820HP with the flat tappet and the Dominator. Peak TQ with the flat was a little better in some cases than the HR or SR but came in at a little higher RPM. The HR was stronger down low and made about the same peak HP as the flat tappet. But the flat tappet could keep on screaming to 7000 rpm and beyond where the HR couldn't.

JIM