There was a another guy on here a while back who had a 413 cam that was out of spec. When an indicator was put on the lifter there where dips in the lift ramps. Not flat spots, dips where the indicator goes back down instead of up. If TA is having someone else grind the cam and using different masters I'd say there was a good chance 413 grinds had a problem that a stamped rocker tolerates and a roller rocker exagerates.
OK... the jury is back in and we have a verdict...... It is a 300 RPM improvement over the 1.6 rollers. It feels totally different and pulls hard to 5000, then hits a wall. With the rollers it was about 4700 and felt like it was way out of the powerband. My 1 - 2 shift was always very sloppy; it felt like it would just hang there and then step into 2nd. Now it hits second so hard that it barks the tires hard! It never did that before with the 1.6 rockers. It is obviously still in the powerband just before it rolls over at 5000. So, overall I say it is an improvement as far as performance goes. I notice that the valvetrain seems quieter as well. However it will never rev to 5300 or 5500 like some of yours do. Not sure why and I really don't care at this point. But I'm satisfied. 300 RPMs and a shift still in the powerband is a huge improvement.
Most excellent:beers2: I think retarding the cam a little bit may help also, because it should still pull higher than it is. But glad to see its better.
Are u going to later upgrade to the 1.55 rollers or stay with the stock set up? The cam being 6 degrees advanced may also be a part of the issue.
Without me going back and re reading the history, isn't this the same reason you pulled the old engine? Chris
Could be. But the old engine had a flat spot from 4000 to 5000, then would pull again from 5000 to 5500. Also, after tearing down the old engine I was lucky I pulled it when I did because it was pretty wasted. Mains were shot, the rear main saddle was all hosed, crack in one of the thread bosses for a head bolt... just a mess. I have it 6* advanced as per Jim Weise and Mike T. They suggest giving up horsepower and RPM to get more torque to move my barge. As long as it pulls hard and stays in the powerband until 5000 I'm happy. it was the laying over at 4700 RPM and nose diving that was bothering me. Besides, having to shift at 5000 will save my engine.
I'm pulling the heads and having Greg Gessler give them a good inspection and flow them. Jim Weise believes the valve tip heights are too high. So I'm having Greg take a look. I don't think it is the cam. Jim is adamant that I should be shifting this thing at 6 grand, even with the cam advanced 6*. And I believe him. So there is a reason a pretty warmed over 455 can't rev over 5000. And I'm going to find it. If the heads are a mess I'll regroup and go from there. I expect to have my heads in Greg's shop in 2 weeks. I'll keep this thread updated as I get more information. Here is the breakdown regarding parts used on the old and new engines... Reused: pistons heads rockers pushrods intake distributor oil pan coil New: block rods crank timing cover oil pump On the dyno the power would drop off at 5200 RPM. On the dyno I used their MSD box, coil and fuel delivery, so I can rule those out in my car because it wouldn't rev on the dyno either. Here's a thought... anybody ever have a problem with one of Dave's HEI's distributors when they are setup as an MSD trigger?
I'm glad you are going to go to the extra effort to get to the root of the problem, I thought you were going to leave us hanging there for a moment. :TU:
I've been using one of Dave's units to trigger my MSD Digital6 for many years Yards. That ain't it. I think you are doing the right thing sending your heads to Greg. If there is something wrong there, it can't be in better hands IMHO.
So it may have not been the roller rockers that caused this issue? A 234/244@.050 cam should be able to pull hard to at least 5800 RPM all day long.
It definately pulls better to 5000 with the 1.55 ratio rockers, I can tell you that much. I can tell just by the 1 - 2 shift that it is in the powerband now where before it was really out of it. But it still hits a wall at 5000. More to follow. I expect to be pulling the engine this weekend at Ivyland Collision (www.GSGarage.com) and after I get the heads back Nick Serwo and I will haul it to the dyno once again and see what we have. My nerves are freaking shot!
Just throwing my experience in using this cam with TA 1.6 rollers, it ran decent (shift points at 5800 rpm): 10:1 compression valve tips were around 2.18" ICL was 107 cranking compression was in the 170 psi range ported iron heads 260/160 cfm @ .5 SP-1 w/800 q-jet 2800 stall and 3.42 gear Hyper pistons M/T headers, x-pipe, 3" exhaust 5/16" adjustable pushrods stage one springs w/damper I did have to keep an eye on pushrod to head clearance it was close in a couple of holes. Ran as good as 12.23 @ 108.5 mph with drag radials. Prior to installing the rollers I had two shafts break at the end then I bit the bullet and went with the 1.6 rollers. Been fine ever since...
I run a 413 cam with 1:55 intake, 1:65 exhaust roller rockers. It used to rev like a mad monkey when I had 10.5:1 CR. Since I dropped it to 9.5:1 for the blower it sucks. New Scott Brown blower cam next year.
