valve sizes..

[427Fastback]

OK...poor choice of words...

[hotrodfeguy]

So your saying Jay that with 10 degrees more duration and .050 more lift the roller lifter is not going to live as long as a solid lobe?  I do not think that cam I pointed out was that much of a radical lobe from what he is running now that it would fail under the same conditions. But I must have missed something. My solid 690/700 lift 240 /250 @.050 has no issue in a center oiler configuration on the street.

[427Fastback]

Hotrodfeguy......How many miles have you put on it....?

I have pondered the idea of building a spray bar system in the valley to spray the lifters (as much as possible)It would be fairly easy to do and there is oil pressure there to be tapped into...I just havent sat down and figured it all out...

Cory

[My427stang]

I am not comfortable with solid rollers on the street.  Although modern lifters are bit better with oiling, I saw some carnage in the early 2000s, no warning, and parts coming apart.  I also agree its from idling and low rpm

When I called Comp back then, they said "300 passes then rebuild the lifters" 

Oiled stuff is certainly better and there have been great improvements, but I dont think even the cam manufacturers would recommend a solid roller on the street. 

I'd run what you have, port the heck out of the heads if the budget allows, or if you want more RPM go with a 282 or 294 or equiv from another company.  I run an Erson grind in my 489, solif flat tappet, and haven't had to adjust the rockers since 2006.  I was checking them each year, but this year I didn't even pull the valve covers LOL

[jayb]

So your saying Jay that with 10 degrees more duration and .050 more lift the roller lifter is not going to live as long as a solid lobe?  I do not think that cam I pointed out was that much of a radical lobe from what he is running now that it would fail under the same conditions. But I must have missed something. My solid 690/700 lift 240 /250 @.050 has no issue in a center oiler configuration on the street.

Going just by the lift and duration numbers is misleading.  Most roller cam profiles have more aggressive ramps, because the roller lifters can use them.  That certainly has an effect.  And the other guys are correct, low speed oiling is a big issue.  I always run the roller lifters with the pin oiling feature (e.g. Crower HIPPO lifters), but that is not the same as running a factory roller lifter where the combination of the lifter and the oiling system in the block is designed to be run for 200,000 miles.

I've run roller lifters on the street since the 1980s, and used to experience a lot of lifter failures even after a couple thousand miles.  Since the pin oiling feature has become available I have not had any trouble, but I don't keep the lifters in for longer than 10,000 miles before I replace them.  You could certainly go longer with milder cams than the ones I'm using, but I wouldn't go so far as to say that aftermarket roller lifters are more durable than a flat tappet lifter.  Despite all the problems with flat tappet cams and lifters over the last several years, they are still a very durable combination once they are in and working properly.

[hotrodfeguy]

I do 50/50 street strip and have a year under the engine but have not done a teardown yet. maybe thats some worth checking now. as I do not have the pin oiling lifter.

[427Fastback]

I'm going to stick with my little 270 flat tappet.It was broken in 1988  and has been good for 20,000 miles.I only ever set my valves out of curiousity to see how they are...I do my own porting so I will pour some hours into the heads..

As for the valves...I will look into some sizes...I dont want to notch the chambers to much to un-shroud them as I am trying to raise the compression not lower it...

Cory

[manofmerc]

427 fastback if this is a street engine I would just stay with the cam you have and valve sizes also .If you were going to the dragstrip I would do a cam swap then larger valves .I have a 66 comet with a 427 I have std. edel. heads about the same compression as you 10.1 .My cam is a lunati 237-247@50 mid 500 lift .I have more than enough power for playing around on the street .If I went drag racing with this on a regular basis I would go to larger valves out of curosity.Just to see what the results are .Your ported heads will give you more air flow than what they originally had .In your case maybe bigger isnt better . Nothing wrong with your comp cam either street engines are more fun when they are torguey .My 427 does have a 428 crank so it has the torque but I imagine your car has more than enough power .Maybe think about a bit more cam after you see how your ported heads run until then enjoy your car .Doug 

[427Fastback]

I have had the car since 1977 and the 427 has been in it since 1988.I was happy with the torque as it was (we always want more) This was with the C8-H heads ported with CJ valves,C7-F intake,stock rockers and CJ manifolds..I figure a substantial gain with the ported 427 E-bok heads,roller rockers,FPA headers and either Jays new 2pc intake or a performer RPM..

It has never been on the track.I built the car for the street and to have fun on our never ending mountain roads.

As I have very little in the way of shock towers any more I may re-think the headers and build my own to make use of the extra room.As Jays book points out that sharp turn could use a inch or two of straight pipe...

Cory