That's what I told myself last winter, and now it's this winter! If all else fails, I'll take you up on that cam offer. Your spare has a bit more lift than the one I ordered.
In the bold, that's a good thing. IIRC the cam you're waiting for could of used more lift to get your $$ worth out of the porting you paid for. I posted that a page or two back, not sure if you seen it or not?
Derek, I just went back and read your post. I must have missed it. I guess it's kinda late now because i already ordered and paid for the cam from TA. 550 lift will be plenty streetable, easy on the valve train, no worries about running pump gas, and probably give me enough vacuum to run my brakes. Yeah there's some power left on the table, but I'm not building an all out racer mostly street. If I plan on doing more track time, I know I can always yank the cam and go bigger.
The beautiful thing about a roller cam is that you can have them ground with more lift and still keep the dur. @ .050" down in the streetable range. It will still have plenty of vacuum as the lower lift cam but will use more of the airflow the heads are capable of with the same dur. @ .050". A flat tappet cam needs to increase dur. @ .050" with more lift to help keep the ramp from getting to aggressive that it wipes itself out where a roller cam to a point, not so much. I can't recall your flow numbers but the biggest roller cam lobe unless they changed them is .365" so you can get to a .602" with TA's 1.65:1 roller rockers and still keep the duration @ .050" streetable. If the cam isn't ground yet, you may be able to change it before it is?
Thanks Sean So I got my cam this morning. The cam card that shipped with the cam is different than what I was told I would be getting. This is the cam card I was told I would be getting: This is the actual cam I received: Lift is .001 under Duration (advertised) is 8 higher Duration (actual) is 1 under Overlap is 1.5 less Exhaust/Intake Open/Close are between .5° and 1° different I assume there are acceptable tolerances +/- when grinding cams. Would these differences fall within tolerance?
Looks like you need to call them. You might have the wrong com. And dang whats with the spring pressure recommended??? Is that right for a roller cam?
Looks like the dual springs i bought with my valves will have to go back. They are rated 100 lbs / 250 lbs Didn't have a chance to call TA yesterday, I'll call when they open today. I'm just wondering if the cam they sent is better or worse for my build?
Ok I talked to Tim @ TA. He told me that the cam is (basically) within spec. TA has cam cards they recommend which when all is said and done, cannot be exactly duplicated. Intake/Exhaust - Open/Close (+/- a degree @ .050) Duration (+/- a degree @ .050) Overlap (actual) was lower than estimated, meaning more low end torque with both valve open less at the same time. The springs I ordered are wrong. Crower recommends 290/120 for this grind. TA has (through testing) proved that those recommended numbers way low. They up the pressure to real world experience with roller cams. The cam card I got says 350/150 springs. He said I can use the 1130 springs @ 325/125 no problem.
Lets talk ignition box, distributor, coil I was running a Malory Unilite distributor. Does anyone make a low profile HEI that will fit under the snorkel? I want a rev limiter. Looks like a lot of people run the MSD6AL ignition box for that and additional spark. I currently have a Mallory coil @ 40,000V. Is that enough? Thanks!
Get a stock distributer converted to electronic by everyday performance, thats all you need is a trigger for a 6al box. Coil will work .
You can also trigger a box with points. The good thing about that is the points carry very little current in that configuration, so there is no wear.
Roller cam spring pressure is higher due to the requirement to ALWAYS keep the roller in contact with the lobe. But even with the higher spring pressure, I have observed that roller cam motors are noticeable easier to turn over by hand, with the plugs out.. due to the massive reduction in friction on cam I am sure. just reviewing this thread to build Kevin a converter, and I thought I would mention that.. JW
Update! Getting closer. Jim should have my carb back from dyno soon. Motor is coming along nicely. I should be ready for install within a month or so!